Visible light sensitive material and preparation method thereof

Visible light sensitive material and preparation method thereof

Figure 1 is an ESR spectrum of the visible light sensitive material of the present invention (Example 1) measured in a vacuum at a temperature of 77K. The upper part is the spectrum under the dark, the middle part is the spectrum under the illumination of the light having a wavelength of 420 nm or more (the light of 420 nm or less is removed from the mercury light), and the lower part is the spectrum irradiated by the mercury light without removing the light of 420 nm or less.

Fig. 2 is an ESR spectrum of the visible light sensitive material of the present invention (Example 1) measured in a vacuum at room temperature. The upper part is the spectrum in the dark, the middle part is the spectrum under the illumination of the light having a wavelength of 420 nm or more (the light of 420 nm or less is removed from the mercury light), and the lower part is the spectrum of the mercury light irradiated with the light of 420 nm or less.

Fig. 3 shows the results of XRD measurement of the product of Example 1 (upper stage) and the hydrolyzate (50 °C of drying) (lower stage).

Figure 4 shows the measurement of the atmosphere as vacuum (upper stage), air (middle stage) or isopropanol (lower stage), and light passing through the filter (L-42) below 420 nm (using 500W high pressure mercury lamp) The measured ESR spectrum under irradiation conditions.

Fig. 5 is a view showing the ESR spectrum measured by the light obtained by irradiating light of 420 nm or less (using a 500 W high-pressure mercury lamp) passing through a filter (L-42) with a product obtained in Example 4 (measuring temperature is 77K).

Fig. 6 is a graph showing the relationship between the NO removal rate and the heating temperature obtained as shown in Example 8.

Figure 7 is a NO obtained as shown in the eighth embodiment. ₂ The relationship between the generation rate and the heating temperature.

Figure 8 is a NO obtained as shown in the eighth embodiment. _X Diagram of removal rate versus heating temperature.

Fig. 9 is a graph showing the relationship between the NO removal rate and the heating temperature obtained as shown in Example 9.

Figure 10 is a NO obtained according to the embodiment 9 ₂ The relationship between the generation rate and the heating temperature.

Figure 11 is a NO obtained according to the embodiment 9. _X Diagram of removal rate versus heating temperature.

Fig. 12 is a graph showing the relationship between the number of times of washing after heating and the rate of NO formation as obtained in Example 10-1.

Figure 13 is a graph showing the number of times of washing after heating and NO as shown in Example 10-1. ₂ A graph of the generation rate.

Figure 14 is a graph showing the number of times of washing after heating and NO as shown in Example 10-1. _X Diagram of the removal rate.

Fig. 15 is a graph showing the relationship between the number of times of washing as shown in Example 10-1 and the pH of the water separated from the material after washing and the chloride ion concentration (using titanium chloride and hydrolyzate as raw materials).

Figure 16 shows the NO of each sample obtained in Example 10-2. _X Remove activity.

Fig. 17 is a view showing the value (A) obtained by dividing the IR spectrum obtained by the cleaning of the example 10-2 by the IR spectrum of the number of times of cleaning by 6 times, and the IR spectrum of the number of times of washing by one time. The number of times of washing is the value obtained by the IR spectrum of 6 times (B).

Fig. 18 is a graph showing the change of the D and E obtained by the sample powder G obtained in Production Example 1, the powders A, B and C obtained in Examples 12-1 to 3, and the D and E obtained in Comparative Examples 12-1 to 2 (Comparative Example). F of 12-3 is a description of the result of measurement by an X-ray diffraction analysis apparatus.

Figure 19 is a view showing the sample powder G obtained in Production Example 1, the powders A, B and C obtained in Examples 12-1 to 3, and the D, E and F obtained in Comparative Examples 12-1 to 3 by a color analyzer. A plot of the reflectance spectrum measured.

Figure 20 is a graph showing the ESR spectrum of a visible light sensitive material of the present invention (Example 12-1) irradiated in a vacuum of 77 K in a vacuum having a wavelength of 420 nm or more (light in a high pressure mercury lamp to remove light below 420 nm).

Fig. 21 is a view showing the ESR spectrum of the visible light sensitive material of the present invention (Example 13) irradiated in a vacuum of 77 K in a vacuum having a wavelength of 420 nm or more (light of 420 nm or less is removed in a high pressure mercury lamp).

Fig. 22 is a view showing the ESR spectrum of the visible light sensitive material of the present invention (Example 14) irradiated in a vacuum of 77 K in a vacuum having a wavelength of 420 nm or more (light in a high pressure mercury lamp to remove light below 420 nm).

Figure 23 is a graph showing the ESR spectrum (upper paragraph, darkness) of the visible light sensitive material of the present invention (Example 7) in nitrogen gas (760 Torr) at 77 K and in the dark; the visible light sensitive material of the present invention (Example) 7) The measured ESR spectrum (middle section, >455 nm) under nitrogen (760 Torr), 77 K, light having a wavelength of 455 nm or more (with light removed above 1455 nm in the xenon lamp); and measured from light irradiation The ESR spectrum is subtracted from the spectrum obtained from the ESR spectrum measured in the dark (lower section, >455 nm-dark).

Technical category

The present invention relates to a visible light sensitive material and a process for its preparation. Furthermore, the present invention relates to a method of sterilizing, preventing algae, mildew and/or staining using a visible light sensitive material, a method of purifying water, and a method of reducing nitrogen oxides contained in the atmosphere.

The visible light sensitive material of the present invention can be used as a photocatalyst, a photosensor, a photocell material, a light antifouling material, a photohydrophilic material, and a photobacterial material.

Background technique

Photocatalysts using sharp-cone type titanium dioxide are known for use in antibacterial tiles, self-cleaning building materials, super-hydrophilic materials, deodorizing and deodorizing materials, as well as purification of water and treatment of cancer (light cleaning revolution (RattanShow him)); the development of various uses is currently flourishing. Specifically, for example, an air treatment method using a photocatalyst under indoor illumination is disclosed in WO94/11092. Japanese Patent Application Laid-Open No. Hei 7-102678 discloses a method of using a photocatalyst to prevent nosocomial infection. An antibacterial coating material is disclosed in Japanese Laid-Open Patent Publication No. Hei. 8-67835. Furthermore, super-hydrophilic materials are disclosed in WO 96/29375.

In each of the above cases, the sharp-cone type titanium dioxide requires ultraviolet rays of 400 nm or less as excitation light. In this regard, in the sunlight or artificial light that can form the excitation light source, there is much more visible light than the ultraviolet light. However, in the photocatalyst formed of the above titanium dioxide, it is unfortunate that the visible light is hardly utilized, and the efficiency is extremely poor from the viewpoint of energy conversion efficiency. Therefore, such inefficiency poses a great obstacle to practical use.

Therefore, the development of photocatalysts that can utilize visible light is also slowly progressing. For example, Japanese Laid-Open Patent Publication No. Hei 10-146530 discloses a titanium oxide-based photocatalyst having a ratio of O/Ti atoms at a deeper layer than the surface to a smaller ratio of O/Ti atoms on the surface. Such a photocatalyst is formed by heating a complex of a titanium alkoxide and a chelating agent (for example, acetamidine) in an oxidizing gas at about 500 °C. However, such a method has a high manufacturing cost due to the use of a titanium alkoxide and a chelating agent (for example, acetamidine), and since the O/Ti atomic ratio of the surface and the inside must be different, it is difficult to control the so-called manufacturing conditions. The problem. Further, in the examples, it was described that the activity was obtained by irradiation with light of 420 nm or more, but the activity obtained was extremely low, which was not practical.

Further, it is known that a catalyst composed of stabilized and oxygen-deficient titanium dioxide is active under visible light irradiation (W000/10706). Such a photocatalyst is obtained by, for example, using ST-01 (manufactured by Ishihara Sangyo Co., Ltd.), which is known as an ultraviolet photocatalyst, as a raw material, and plasma treatment with hydrogen or argon. ST-01, a product of the Ishihara industry, is a substance mainly active for ultraviolet rays. However, as shown in Table 5 (powder F), it exhibits activity toward visible light near 420 nm, but appears to be quite low compared to the activity against ultraviolet rays. It has substantially no activity above 470 nm. In this regard, the photocatalyst described in the above-mentioned W000/10706 is not limited to light having a wavelength of around 420 nm, and light of a wavelength of about 600 nm can also be used to oxidize NO light to be a photocatalyst of a true visible light type.

However, due to the use of plasma treatment, a pressure reduction system becomes necessary. As a result, there is a problem of "processing of powder, especially that uniform mixing becomes difficult and unsuitable for continuous production".

Further, a general wet preparation method of sharp-cone type titanium oxide is known as (1) a method of hydrolyzing a titanium-containing solution such as titanyl sulfate or titanium sulfate, and (2) a method of hydrolyzing an organic titanium compound such as a titanium alkoxide. And (3) a method of calcining a precipitate obtained by neutralizing or hydrolyzing a titanium halide solution such as titanium tetrachloride.

As described above, although development tests using a visible light photocatalyst using alkoxytitanium oxide have been conducted, visible light photocatalysts and visible light sensitive materials using inexpensive titanium sulfate or titanium chloride as raw materials have not been known until now.

Accordingly, it is an object of the present invention to provide a novel photosensitive material which can be manufactured inexpensively and which is sensitive to visible light and a process for the preparation thereof.

Invention disclosure

The present invention relates to a visible light sensitive material characterized in that it contains at least a sharp-cone type titanium oxide, and in the vacuum and at a temperature of 77 K, when the ESR is measured by irradiation with light having a wavelength of 420 nm or more, the g value can be observed. The main signal of 2.004 to 2.07 and the two sub-signals with g values of 1.985 to 1.986 and 2.024, and only three weak signals are observed in vacuum, at a temperature of 77K and in the dark, or substantially not observed.

Furthermore, the present invention relates to a process for producing a visible light sensitive material characterized by the presence of amorphous or incompletely crystalline titanium oxide and/or titanium hydroxide (raw material titanium compound) in the presence of ammonia or a derivative thereof. A method of heating wherein the heating is terminated when the generated material absorbs light having a wavelength of 450 nm greater than the absorption of the raw material titanium compound with respect to light having a wavelength of 450 nm.

Simple illustration

Figure 1 is an ESR spectrum of the visible light sensitive material of the present invention (Example 1) measured in a vacuum at a temperature of 77K. The upper part is the spectrum under the dark, the middle part is the spectrum under the illumination of the light having a wavelength of 420 nm or more (the light of 420 nm or less is removed from the mercury light), and the lower part is the spectrum irradiated by the mercury light without removing the light of 420 nm or less.

Fig. 2 is an ESR spectrum of the visible light sensitive material of the present invention (Example 1) measured in a vacuum at room temperature. The upper part is the spectrum in the dark, the middle part is the spectrum under the illumination of the light having a wavelength of 420 nm or more (the light of 420 nm or less is removed from the mercury light), and the lower part is the spectrum of the mercury light irradiated with the light of 420 nm or less.

Fig. 3 shows the results of XRD measurement of the product of Example 1 (upper stage) and the hydrolyzate (50 °C of drying) (lower stage).

Figure 4 shows the measurement of the atmosphere as vacuum (upper stage), air (middle stage) or isopropanol (lower stage), and light passing through the filter (L-42) below 420 nm (using 500W high pressure mercury lamp) The measured ESR spectrum under irradiation conditions.

Fig. 5 is a view showing the ESR spectrum measured by the light obtained by irradiating light of 420 nm or less (using a 500 W high-pressure mercury lamp) passing through a filter (L-42) with a product obtained in Example 4 (measuring temperature is 77K).

Fig. 6 is a graph showing the relationship between the NO removal rate and the heating temperature obtained as shown in Example 8.

Figure 7 is a NO obtained as shown in the eighth embodiment. ₂ The relationship between the generation rate and the heating temperature.

Figure 8 is a NO obtained as shown in the eighth embodiment. _X Diagram of removal rate versus heating temperature.

Fig. 9 is a graph showing the relationship between the NO removal rate and the heating temperature obtained as shown in Example 9.

Figure 10 is a NO obtained according to the embodiment 9 ₂ The relationship between the generation rate and the heating temperature.

Figure 11 is a NO obtained according to the embodiment 9. _X Diagram of removal rate versus heating temperature.

Fig. 12 is a graph showing the relationship between the number of times of washing after heating and the rate of NO formation as obtained in Example 10-1.

Figure 13 is a graph showing the number of times of washing after heating and NO as shown in Example 10-1. ₂ A graph of the generation rate.

Figure 14 is a graph showing the number of times of washing after heating and NO as shown in Example 10-1. _X Diagram of the removal rate.

Fig. 15 is a graph showing the relationship between the number of times of washing as shown in Example 10-1 and the pH of the water separated from the material after washing and the chloride ion concentration (using titanium chloride and hydrolyzate as raw materials).

Figure 16 shows the NO of each sample obtained in Example 10-2. _X Remove activity.

Fig. 17 is a view showing the value (A) obtained by dividing the IR spectrum obtained by the cleaning of the example 10-2 by the IR spectrum of the number of times of cleaning by 6 times, and the IR spectrum of the number of times of washing by one time. The number of times of washing is the value obtained by the IR spectrum of 6 times (B).

Fig. 18 is a graph showing the change of the D and E obtained by the sample powder G obtained in Production Example 1, the powders A, B and C obtained in Examples 12-1 to 3, and the D and E obtained in Comparative Examples 12-1 to 2 (Comparative Example). F of 12-3 is a description of the result of measurement by an X-ray diffraction analysis apparatus.

Figure 19 is a view showing the sample powder G obtained in Production Example 1, the powders A, B and C obtained in Examples 12-1 to 3, and the D, E and F obtained in Comparative Examples 12-1 to 3 by a color analyzer. A plot of the reflectance spectrum measured.

Figure 20 is a graph showing the ESR spectrum of a visible light sensitive material of the present invention (Example 12-1) irradiated in a vacuum of 77 K in a vacuum having a wavelength of 420 nm or more (light in a high pressure mercury lamp to remove light below 420 nm).

Fig. 21 is a view showing the ESR spectrum of the visible light sensitive material of the present invention (Example 13) irradiated in a vacuum of 77 K in a vacuum having a wavelength of 420 nm or more (light of 420 nm or less is removed in a high pressure mercury lamp).

Fig. 22 is a view showing the ESR spectrum of the visible light sensitive material of the present invention (Example 14) irradiated in a vacuum of 77 K in a vacuum having a wavelength of 420 nm or more (light in a high pressure mercury lamp to remove light below 420 nm).

Figure 23 is a graph showing the ESR spectrum (upper paragraph, darkness) of the visible light sensitive material of the present invention (Example 7) in nitrogen gas (760 Torr) at 77 K and in the dark; the visible light sensitive material of the present invention (Example) 7) The measured ESR spectrum (middle section, >455 nm) under nitrogen (760 Torr), 77 K, light having a wavelength of 455 nm or more (with light removed above 1455 nm in the xenon lamp); and measured from light irradiation The ESR spectrum is subtracted from the spectrum obtained from the ESR spectrum measured in the dark (lower section, >455 nm-dark).

Best mode for carrying out the invention

The visible light sensitive material of the present invention has at least a sharp-cone type titanium oxide, and when the ESR is measured by irradiation with light having a wavelength of 420 nm or more in a vacuum at a temperature of 77 K, a g value of 2.004 to 2.007 can be observed. The main signal (the strongest signal) and the two sub-signals with a g value of 1.985 to 1.986 and 2.024 (signals with lower intensity than the main signal). Furthermore, the visible light sensitive material of the present invention is characterized in that the above three signals (main signal and two sub-signals) are in a vacuum, 77K and dark, only weak signals are observed, or substantially not observed.

Further, in the present invention, light having a wavelength of 420 nm or more used for ESR, as described in the embodiment, is a filter for transmitting light from a high-pressure mercury lamp (for example, 500 W) through light capable of removing light having a wavelength of 420 nm or less (L-42). And get the light.

Furthermore, in the visible light sensitive material of the present invention, some of the light having a wavelength of 455 nm or more in a vacuum and at 77 K [transmission of light from a xenon lamp (for example, 150 W) through a filter capable of removing light having a wavelength of 455 nm or less The ESR measured under the irradiation of the device (GG-455) can also observe the main signal with the g value of 2.004 to 2.07 (the strongest signal), and the g value of 1.985 to 1.986 and 2.024 Sub-signal (signal with lower intensity than the main signal).

The visible light photocatalyst composed of the stabilized oxygen-deficient titanium dioxide described in the above W000/10706 also has a special ESR spectrum. However, the ESR spectrum of the visible light photocatalyst is described in W000/10706. In the vacuum, the ESR measured at 77K and in the dark has only a g value of 2.003 to 2.004, and the visible light sensitive material of the present invention described above. The spectrum displayed is different.

The visible light sensitive material of the present invention is preferably titanium oxide having a sharp cone type titanium oxide as a main component, and may also contain amorphous titanium oxide. Alternatively, rutile-type titanium oxide may be additionally contained. Further, the sharp-cone type titanium oxide does not necessarily have to have high crystallinity. Further, in the titanium oxide constituting the visible light sensitive material of the present invention, the ratio of titanium to oxygen is not necessarily, specifically, the theoretical ratio of the chemical amount of titanium dioxide relative to the amount of oxygen of titanium (theoretical value is 2.00). It is also good for the few. In the case of the titanium oxide in the visible light sensitive material of the present invention, the molar ratio of oxygen to titanium may be, for example, less than 2.00, for example, 1.00 to 1.99 or 1.50 to 1.99. The molar ratio of oxygen to titanium in the titanium oxide in the visible light sensitive material of the present invention can be measured, for example, by X-ray photoelectron spectroscopy.

The typical ESR spectrum of the visible light sensitive material of the present invention measured in vacuum and at a temperature of 77 K is shown in Fig. 1. The upper part of the figure is the spectrum under the dark, and the middle part is the spectrum under the illumination of light having a wavelength of 420 nm or more (removing light below 420 nm in the mercury light). The lower section is the spectrum of mercury light that has not been removed by light below 420 nm. Further, any of the upper, middle and lower sections is the result of measurement under the same amplification factor (GAIN).

In the spectrum of the upper part of Fig. 1, a weak g value of 2.004 to 2.07 is observed, and the two sub-signals with g values of 1.985 to 1.986 and 2.024 are substantially unobservable. Furthermore, if the spectrum of the upper part of Fig. 1 is compared with the spectrum of the middle stage, the main signal of the g value of 2.004 to 2.07 in the spectrum of the middle stage and the two sub-signals of the g value of 1.985 to 1.986 and 2.024 are compared with the upper spectrum. The middle is obviously much stronger. Moreover, if the middle and lower sections of the first graph are compared, the g value is the main signal of 2.004 to 2.007 and the intensity of the two sub-signals having g values of 1.985 to 1.986 and 2.024, regardless of whether or not the illumination light contains 420 nm or less. There is no substantial difference between the light.

Furthermore, the visible light sensitive material of the present invention, as shown in Fig. 2, can observe a weak g value of 2.004 to 2.07 in a vacuum, at room temperature and in the dark, and a g value of 1.985 to 1.986 and The two sub-signals of 2.024 are virtually invisible. Further, the above three signals can be measured in a vacuum and at a normal temperature in an ESR irradiated with light having a wavelength of 420 nm or more and mercury light having no light of 420 nm or less. In the second figure, the upper part is the spectrum under the dark, and the middle part is the spectrum irradiated with light having a wavelength of 420 nm or more (removing light of 420 nm or less in the mercury light). The lower section is the spectrum illuminated by mercury light that does not remove light below 420 nm. Further, any of the upper, middle and lower sections is the result of measurement under the same amplification factor (GAIN). .

Furthermore, it is presumed that the above three signals in the visible light sensitive material of the present invention are attributed to the radicals caused by the filling of the positron holes. This is also illustrated in the examples, from the ESR spectrum in the atmosphere of isopropanol (which is an electron supply molecule) and the ESR spectrum in the atmosphere of air (oxygen in the air is an electron accepting molecule).

The visible light sensitive material of the present invention has a sub-signal having a g value of 2.009 to 2.010 in addition to the above signal in a vacuum and 77 K under irradiation with light having a wavelength of 420 nm or more. The g signal has a sub-signal of 2.009 to 2.010, as shown by the ESR spectrum in the middle of Figure 1.

The visible light sensitive material of the present invention, as described above, has a specific ESR signal, but is also colored, for example, when the light reflectance for a wavelength of 600 nm is set to 1 (or 100%), the wavelength is 450 nm. The light reflectance is 0.85 (or 85%) or less, preferably 0.80 (or 80%) or less, and more preferably 0.70 (or 70%) or less. The greater the coloring property, the stronger the tendency of the visible light sensitive activity. The reflectance therein is the result measured by a spectrophotometer as shown in the examples below. Further, although the reflectance can be measured by a color analyzer, since the accuracy of the spectrophotometer is excellent, the evaluation of the reflectance is performed using a spectrophotometer.

The visible light sensitive material of the present invention, as described above, is a person having a specific ESR signal, and as described in detail and in detail in the examples, has an oxidation activity of NO under light irradiation in the visible light region. Specifically, the oxidation activity of NO can be exhibited by at least irradiation of visible light having a wavelength of 520 nm or less. More preferably, the material exhibits an oxidation activity of NO by irradiating visible light having a wavelength of 570 nm or less.

The visible light sensitive material of the present invention can be produced by using amorphous or incompletely crystalline titanium oxide (including aqueous titanium oxide) and/or titanium hydroxide as a raw material. The raw material titanium compound is obtained by a wet method such as a sulfuric acid method or a chloride method. More specifically, the raw material titanium compound may be obtained by hydrolyzing titanium chloride or titanium sulfate to ammonium hydroxide. Alternatively, the raw material titanium compound may be obtained by hydrolyzing a titanium alkoxide or hydrolyzing the titanium alkoxide in an aqueous ammonium hydroxide solution. However, from the viewpoint of inexpensive raw materials, in industrial production, it is preferred to hydrolyze titanium chloride or titanium sulfate in an aqueous ammonium hydroxide solution. Therefore, the case of hydrolyzing titanium chloride or titanium sulfate in ammonium hydroxide will be explained below.

In the above-mentioned hydrolysis, for example, an aqueous ammonium hydroxide solution may be continuously or intermittently added to an aqueous solution of titanium chloride or an aqueous solution of titanium sulfate, or an aqueous solution of titanium chloride or an aqueous solution of titanium sulfate may be continuously or intermittently added to hydrogen. It is carried out in an aqueous solution of ammonium oxide. The concentration of the aqueous solution of titanium chloride, the aqueous solution of titanium sulfate, and the aqueous solution of ammonium hydroxide can be appropriately determined. In the hydrolysis, it is preferred to adjust the amount of ammonium hydroxide added so that the final pH of the reaction liquid becomes alkaline. The titanium chloride may also be titanium trichloride or titanium tetrachloride, or may be a mixture thereof. The above hydrolysis can be carried out, for example, at a temperature of from 0 ° C to 100 ° C, preferably from 20 to 80 ° C, but from the viewpoint of low crystallinity or availability of amorphous titanium oxide at room temperature It is preferred to add water to it.

The hydrolyzed product obtained from ammonium chloride or titanium sulfate by ammonium hydroxide is preferably washed with water or an aqueous solution of ammonium hydroxide and used as a raw material titanium compound. The aqueous decomposition product is washed with water or an aqueous ammonium hydroxide solution, for example, by filtering the reaction liquid containing the hydrolyzate, and then passing water or an aqueous ammonium hydroxide solution through the filtered hydrolyzate. In this method, since water or an aqueous ammonium hydroxide solution is directly added to the filtered hydrolyzed product, the filtration operation is easy, which is preferable. The water-splitting substance is washed with water or an aqueous ammonium hydroxide solution, and the above-mentioned method can be carried out, for example, by resuspending the filtrate of the hydrolyzed product in water or an aqueous ammonium hydroxide solution, and then filtering the suspended matter. . The washing of the water or the aqueous ammonium hydroxide solution may be carried out until the residual amount of the ammonium salt such as ammonium chloride or ammonium sulfate formed during the hydrolysis is reduced to an appropriate amount, or may be carried out as many times.

Further, as the amorphous or incompletely crystalline titanium dioxide, a commercially available product can be used. For example, titanium oxide of incomplete crystallinity such as ST-01 or C-02 manufactured by Ishihara Seiki Co., Ltd. can be used.

In the production method of the present invention, a raw material titanium compound such as amorphous or incomplete crystalline titanium oxide is heated in the presence of ammonia or a derivative thereof. Ammonia can be a liquid or a gas. In the case of using ammonia gas, the raw material titanium compound is heated under an ammonia atmosphere. Further, when the ammonia derivative is an ammonium salt such as ammonium hydroxide or ammonium chloride, for example, the raw material titanium compound is heated in the presence of ammonium hydroxide or ammonium chloride.

The heating of the raw material titanium compound in the presence of ammonia or a derivative thereof is carried out by stopping the heating described above when the absorption of light at a wavelength of 450 nm by the material formed by heating is greater than the absorption of the light of the raw material titanium compound to a wavelength of 450 nm. The raw material titanium is white, and the absorption of light at a wavelength of 450 nm is usually about 10%. When the raw material titanium compound is heated in the presence of ammonia or a derivative thereof, it is slowly colored into yellow. However, such a coloring peak fades with time and eventually exhibits the same level of absorption as the raw titanium compound. The absorption of light at a wavelength of 450 nm varies depending on the type of the raw material titanium compound, the type and amount of ammonia (or a derivative thereof) coexisted, the temperature and time of heating, and the like, and may be up to about 60%. The characteristics of the visible light sensitive material are determined not only by the absorption intensity of light having a wavelength of 450 nm, but also when the absorption of light having a wavelength of 450 nm is 15% or more (reflectance of 85% or less), it is apparent that visible light sensitivity is exhibited. Material. Therefore, the above heat treatment conditions are preferably set such that when the reflectance of light having a wavelength of 600 nm is set to 1 (or 100%), the reflectance of light having a wavelength of 450 nm can be made 0.85 (or 85%). The following conditions are preferably 0.80 (or 80%) or less, more preferably 0.70 (or 70%) or less. The reflectance therein is a result measured by a spectrophotometer as shown in the examples described later.

The above heating conditions are not necessarily limited to the temperature, but the temperature used may be, for example, a temperature in the range of 250 to 550 °C. Find NO _X The relationship between the removal (oxidation) activity and the heating temperature (heating time is set to 1 hour) is as shown in Figs. 6 to 8. Figure 6 shows the NO removal rate, and Figure 7 shows the NO. ₂ Generation rate, and Figure 8 shows NO _X Removal rate (details are as shown in Example 8). From these figures, we can see that NO by 420nm and 470nm wavelength light _X The removal rate is higher when heated in the range of 300 to 450 ° C, and higher when heated in the range of 325 to 425 ° C; and further, by the light of 520 nm and 570 nm wavelength _X The removal rate is higher when heated in the range of 325 to 450 ° C, and higher when heated in the range of 350 to 425 ° C. Therefore, from the field of visible light NO _X The viewpoint of high removal rate is that heating in the range of 350 to 425 ° C is optimal.

Furthermore, find NO _X The relationship between the removal (oxidation) activity and the heating time (heating temperature is set to 400 ° C) is shown in Figures 9 to 11. Figure 9 shows the NO removal rate, and Figure 10 shows the NO. ₂ Generation rate, and Figure 11 shows NO _X Removal rate (details are as shown in Example 9). This figure obtains good NO from light irradiation in the visible light field at wavelengths of 520 nm and 570 nm. _X From the viewpoint of the removal rate, the heating time is preferably 30 minutes or more, and more preferably 1 hour or more. Furthermore, when the heating time is longer than 1 hour, due to NO _X The removal rate has not changed much, so the maximum is about 3 hours.

Furthermore, such heating can be carried out under normal pressure. Further, the heating time can be appropriately determined by using the material generated by heating as an index of absorption of light having a wavelength of 450 nm.

The above heating can be carried out using a rotary kiln, a tunnel kiln or a muffle (Muffle) which is generally used in this category. The particles of the titanium oxide are agglomerated by heating and sintered, and may be pulverized by a pulverizer as needed.

Further, the material obtained by heating as described above may be washed with water or an aqueous solution as needed. By such washing, the visible light sensitivity of the resulting visible light sensitive material can often be improved. Further, when it is not washed, a material having good visible light sensitivity may be obtained depending on conditions.

Amorphous or incompletely crystalline titanium oxide (the raw material titanium compound before heating), for example, if the titanium chloride is hydrolyzed with ammonium hydroxide, a considerable amount remains in the hydrolyzed product. The ammonium chloride, as a result, may change the visible light sensitive material obtained by heating the amorphous or incomplete crystalline titanium oxide at a set temperature as described above. However, after heat treatment, a considerable amount of ammonium chloride remains in the resulting material. In this case, the visible light sensitivity of the visible light sensitive material can often be improved by washing with water or a suitable aqueous solution to remove ammonium chloride. For example, find the number of wash blows and NO _X A diagram showing the relationship of the removal (oxidation) activity is shown in Figures 12 to 14. Figure 12 shows the removal rate of NO, and Figure 13 shows NO. ₂ The generation rate, Figure 14 shows NO _X The removal rate (details are as shown in Example 10-1). From these figures, you can see that if the number of washings increases, NO _X The removal (oxidation) activity is increased, and it is understood that the cleaning has an effect of improving visible light sensitivity.

Further, in this case, the material obtained by heating is washed with water or an aqueous solution, preferably in such a manner that the pH of the water or the aqueous solution separated from the material after washing is, for example, 3 or more (pH 3.5 to 7). Or the amount of chloride ion (in the case of using titanium chloride as a raw material for the hydrolysis of water) or the amount of sulfate ion (in the case of using titanium sulfate as a raw material for the hydrolysis of water) in the water or aqueous solution separated from the material after washing is reduced. Way to proceed. For example, the results of an experiment showing the relationship between the number of times of washing and the pH value of water separated from the material after washing and the chloride ion concentration (using titanium chloride as a raw material for hydrolysate) are shown in Fig. 15. The number of washings in Fig. 15 is the same as the number of washings in the above Figs. 12 to 14.

Further, the degree of ammonium ion remaining in the washed sample heated by the same method was examined, although the washing conditions were different, and the results are shown in Fig. 17 (details are as shown in Example 10-2). From this result, it can be understood that the amount of residual ammonium ions (adhesion weight) can also be reduced by washing.

The visible light sensitive material of the present invention may also be a powder or a film (film) which may be provided on a suitable substrate. The film (film) can be formed by applying a raw material titanium compound such as amorphous or incompletely crystalline titanium oxide to a substrate, and optionally coating with a suitable binder to make ammonia or The derivative is contained in the coating film, or ammonia or a derivative thereof is present in the atmosphere, and then the above heating is carried out. Alternatively, a film (film) may be formed by applying a visible light sensitive material of the present invention in a powder state to a substrate or the like.

The visible light sensitive material of the present invention may also be used for elements such as bismuth, aluminum, tin, zirconium, lanthanum, phosphorus, platinum, gold, silver, copper, iron, lanthanum, tungsten and cerium, and compounds containing the elements according to the use. Covered, loaded or doped on its surface and/or inside.

By using the visible light sensitive material of the present invention, a method of sterilizing, anti-algae, mildewproof and/or antifouling can be provided. Further, by using the visible light sensitive material of the present invention, a method of purifying water and a method of reducing nitrogen oxides in the atmosphere can be provided.

[Examples]

The following examples of the invention are illustrated, however, the invention is not limited by the embodiments.

Example 1

500 g of titanium tetrachloride (manufactured by Kanto Chemical Co., Ltd., special grade) was added to ice water of pure water (made of 2 liters of water), stirred and dissolved to obtain an aqueous solution of titanium tetrachloride. The 200 g of this aqueous solution was stirred with a stirrer while adding about 50 ml of ammonia water (containing 13% by weight of NH) as quickly as possible. ₃ ). The amount of ammonia added was adjusted so that the final pH of the aqueous solution became 8. Thereby, the aqueous solution becomes a white slurry. After further stirring for 15 minutes, it was filtered with a suction filter. Disperse the filtered precipitate in 20 ml of ammonia (containing 6 wt% NH) ₃ In the mixture, after stirring for 20 minutes by a stirrer, the filtrate was again suctioned to obtain a white hydrolyzed product.

The obtained white hydrolyzed product was transferred to a crucible, and heated in the air at 400 ° C for 1 hour in an electric furnace to obtain a yellow product.

The XRD measurement results of the obtained product are shown in the upper part of Fig. 3. Meanwhile, the XRD measurement results of the white hydrolyzate dried at 50 ° C are shown in the lower part of Fig. 3. From the results, it was found that the white hydrolyzate was amorphous at 50 ° C and the resultant product was a sharp-cone-type titanium oxide.

The diffuse reflection spectrum of the obtained product and the white hydrolyzate at 50 ° C was measured by the Hitachi automatic spectrophotometer (U-3210) provided with an integrating sphere under the following conditions.

Scanning speed: 120 nm/min Response: moderate band pass: 2.00 nm reference standard: barium sulfate results, when the resulting product has a reflectance of 600% at 600 nm, the reflectance at 450 nm is 61%; The white hydrolyzate was dried at 50 ° C, and when the reflectance at 600 nm was set to 100%, the reflectance at 450 nm was 95%. Further, when the reflectance at 700 nm was set to 100%, the reflectance at 450 nm was 61%; the white hydrolyzate was dried at 50 ° C, and the reflectance at 700 nm was set to 100. At %, the reflectance at 450 nm is 95%.

Further, the ESR spectrum of the obtained product was measured. The ESR apparatus was ES-RE2X (manufactured by JEOL Ltd.), and the measurement was carried out in a vacuum (0.1 Torr or less) at 77 K or normal temperature. The measurement conditions are as follows.

[Basic parameters]

Measurement temperature: 77K or normal temperature range: 324mT±25mT Scanning time: 4 minutes Amplitude modulation: 0.1mT receiver. Magnification factor: 10 to 100 (measurement sensitivity) Time constant: 0.1 second RF power: 0.1mW Light source: High pressure mercury lamp 500W filter : L-42 (made by Asahi Glass Co., Ltd.)

[sample preparation]

Vacuum degassing: more than 1 hour

[calculation of g value]

Mn ⁺² Mark (g _Mn =1.981 (the third from the high magnetic field side)) is the reference g=g _Mn ×H _Mn /(H _Mn +H)H _Mn :Mn ⁺² Marked magnetic field, H: from H _Mn The calculated magnetic field change amount is shown in Fig. 1 (measurement temperature is 77K) and Fig. 2 (measurement temperature is normal temperature), the upper part is the ESR spectrum in the dark, and the middle part is the light irradiation state passing through the filter (L-42). The lower measured ESR spectrum is a 500W high pressure mercury lamp that removes light below 420 nm. The lower part is the ESR spectrum measured without using a filter capable of removing light below 420 nm (L-42) under a high-pressure mercury lamp of 500 W.

If the spectrum of the upper part and the middle part of the first picture are compared, the main signal of the g value of 2.004 to 2.07 and the two sub-signals of the g value of 1.985 to 1.986 and 2.024 are significantly stronger than those of the upper part. Furthermore, if comparing the spectrum of the middle and lower sections of the first graph, the g signal has a main signal of 2.004 to 2.07 and the intensity of two sub-signals with g values of 1.985 to 1.986 and 2.024, regardless of whether the illumination light contains 420 nm or less. There is virtually no difference in either light.

Further, as shown in Fig. 2, the visible light sensitive material of Example 1 can be measured even in the atmosphere, at room temperature and in the dark, and in ESR obtained by irradiation with light having a wavelength of 420 nm or more. The above three signals.

Further, the white hydrolyzate was dried at 50 ° C, the g signal was a main signal of 2.004 to 2.007, and the two sub-signals having a g value of 1.985 to 1.986 and 2.024 were not observed under any of the ESR measurement conditions.

The measurement atmosphere is changed from vacuum to air or isopropyl alcohol, and is irradiated with light of 420 nm or less by a filter (L-42) (using a 500 W high-pressure mercury lamp), and measured in the same manner as above. ESR spectrum. The result is shown in Fig. 4. The upper part of the figure is in the vacuum, the middle part is air, and the lower part is the measurement result in isopropanol. Both the main signal and the two sub-signals are the smallest in vacuum, slightly larger in isopropyl alcohol than in vacuum, and the largest in the middle air. Relative to isopropanol as the electron supply molecule, the oxygen in the air is an electron accepting molecule. The above results show that the above three signals are attributed to the free radicals caused by the acupoints.

Example 2

The white hydrolyzed product obtained in Example 1 was heated under the same conditions as in Example 1 except that the heating time was changed to 20 minutes or 3 hours to obtain a yellow product. The diffusion reflection spectrum of these products was measured in the same manner as in Example 1. When the sample was heated for 20 minutes, the reflectance at 450 nm was 69% when the reflectance at 600 nm was set to 100%, and the reflectance at 450 nm when the reflectance at 600 nm was set to 100% when the sample was heated for 3 hours. It is 68%. The sample heated for 20 minutes, when the reflectance at 700 nm was set to 100%, the reflectance at 450 nm was 68%, and the sample heated for 3 hours, when the reflectance at 700 nm was set to 100%, the reflectance at 450 nm was 68%. .

Example 3

A white hydrolyzate was obtained under the same conditions as in Example 1 except that titanium tetrachloride was replaced by titanium trichloride, and the white hydrolyzate was heated at 400 ° C for 1 hour to obtain a yellow product. For this product, in the light irradiation state (using a 500 W high-pressure mercury lamp) in which light of 420 nm or less is removed by a filter (L-42), the measured ESR spectrum (measurement temperature 77 K) is displayed with 1 The main signal of the same g value and the two sub-signals shown in the middle of the figure.

Example 4

1.6 kg of sharp-cone type titanium dioxide powder (C-02 manufactured by Ishihara Sangyo Co., Ltd.) was filled in a heating container having an inner volume of 25 liters and an inner wall having a damper plate, and the heater was installed in an external heat type slewing. In the kiln plant. The inside of the heating vessel was flushed with nitrogen, and then ammonia gas was passed at a rate of 1.5 liter/min in terms of nitrogen gas. At the same time, the temperature in the vessel was changed to 400 ° C by an external heater, and the vessel was heated while heating for 90 minutes. After heating, it was cooled to room temperature to obtain a yellow product. The ESR spectrum (measured temperature: 77 K) measured in the light irradiation state (using a 500 W high-pressure mercury lamp) in which light of 420 nm or less was removed by a filter (L-42) is shown in Fig. 5.

Example 5

3 g of the powder obtained in Example 1 was suspended in 100 ml of pure water, and stirred for 1 hour using a magnet stirrer. The resulting solution was subjected to suction filtration. The sample remaining on the filter paper was again stirred in pure water and subjected to suction filtration. The filtration system was carried out until the filtrate was tested with a pH test paper at 6 to 7 hours, and thus repeated three times.

The obtained powder was placed in a desiccator set at 110 ° C for one night to dry it to obtain a material of the present invention.

Example 6

23 kg of titanium tetrachloride was slowly added to 207 kg of water filled with a temperature of 0 ° C in a 300 liter reaction vessel (cooling and stirring). At this time, the temperature of the aqueous solution was at most 6 °C. The titanium chloride was stirred for 2 days to prepare a transparent aqueous solution of titanium tetrachloride. While the prepared titanium tetrachloride aqueous solution was stirred while dropping 12.5% ammonia water, the solution gradually became cloudy, and the amount of the ammonia water was adjusted so that the pH of the white turbid solution was 8.

The white turbid solution was subjected to suction filtration. The white turbid precipitate remaining on the filter paper was 131 kg. Disperse the white precipitate in 200 kg of ammonia (containing 6% NH) ₃ After that, the mixture was stirred for 24 hours, and suction filtration was performed. The white precipitate which was filtered off was 108 kg. The white precipitate was placed in a forced air shed type dryer set to 50 ° C and dried for 4 days. After drying, the sample was 17 kg.

1 kg of the dried sample was placed in an aluminoxane (20 × 20 × 5 cm), and then the crucible was placed in a gas furnace, and a thermocouple was placed on the surface of the sample so that the temperature of the sample became 400 ° C. Calcined for 1 hour.

After cooling, a dark yellow inventive material was obtained. This material was pulverized in a mortar and evaluated for use as described later.

Example 7

3 g of the powder prepared in Example 6 was suspended in 100 ml of pure water and stirred for 1 hour using a magnet stirrer. The resulting solution was subjected to suction filtration. The sample remaining on the filter paper was again stirred in pure water and subjected to suction filtration. The filtration system was carried out until the filtrate was tested with a pH test paper at 6 to 7, so that 3 blowing was repeated.

The obtained powder was placed in a desiccator set at 110 ° C for one night to dry it to obtain a material of the present invention.

The ESR of the obtained material of the present invention was measured. The ESR was measured using JEOL JES-TE300. The measurement conditions were: temperature 77K, atmosphere nitrogen (760 Torr), center range 330mT±25mT, frequency modulation 100kHz, RF power 1.0mW, scan time 4 minutes, time constant For 0.1 second, the light source is a 150W xenon lamp (using Super Bright-152S from Sanyong Electric Co., Ltd.), and the light is irradiated to the sample by a filter GG455 (manufactured by Scottrade Japan Co., Ltd.). And measured.

The results are shown in Figure 23.

[Test example]

NO _X The activity of the samples prepared in Examples 1, 3, 5, 6 and 7 and 0.2 g of each of the commercially available titanium oxide powder (ST-01, manufactured by Ishihara Sangyo Co., Ltd.) (Comparative Example 1) were respectively applied. The glass piece (6 x 6 cm) was placed in a reaction vessel made of Pyrex glass (160 mm inner diameter, 25 mm thick). In the light source, monochromatic light having a half width of 20 nm was irradiated by using a 300 W xenon lamp irradiation apparatus (manufactured by JASCO Corporation, trade name: SM-5 type CT-10).

Simulated contaminated air (NO: 1 ppm) with a humidity of 0% RH was continuously supplied to the reaction vessel at a flow rate of 1.5 liters/min, and NO and NO were monitored at the reaction outlet. ₂ The concentration changes. The concentration of NO is determined by chemiluminescence using ozone. From the cumulative value of the monitored value of 1 hour, the NO at each measurement wavelength is obtained. _X Removal rate (%) (=NO reduction rate -NO ₂ Generation rate). Further, the concentration measurement of NO was carried out using a Model 8840 Nitrogen Oxide Analyzer manufactured by Monitor Laboratories.

<tables><img file="TW548240B_D0001.tif" /></tables>

Example 8 (heating temperature and NO

X

Relationship of removal rate)

The white precipitate obtained in Example 6 (water-splitting substance) was changed to 300 ° C, 325 ° C, 350 ° C, 375 ° C, 400 ° C, 425 ° C, 450 ° C, 475 ° C or 500 ° C, in addition to the heating temperature. The mixture was heated under the same conditions (heating time: 1 hour) as in Example 1, and washed and dried in the same manner as in Example 7 to give a yellow product. The diffuse reflection spectrum of these products was measured, and when the reflectance at 600 nm and 700 nm was set to 100%, the reflectance at 450 nm was as shown in Table 2. The reflectance of ST-01 manufactured by Ishihara Industry Co., Ltd. as a reference is also shown in Table 2. Also, the NO of each sample _X The activity was measured in the same manner as in the above test examples, and the results are shown in Figures 6 to 8.

<tables><img file="TW548240B_D0002.tif" /></tables>

Example 9 (Relationship between heating time and NO removal rate)

The white precipitate (hydrolyzed product) obtained in Example 6 was changed to the same conditions as in Example 1 except that the heating time was changed to 0.5 hour, 1 hour, 3 hours, 6 hours or 10 hours (heating temperature 400 ° C). After heating, it was washed and dried in the same manner as in Example 7 to obtain a yellow product. The diffuse reflection spectrum of these products was measured, and when the reflectance at 600 nm and 700 nm was set to 100%, the reflectance at 450 nm was as shown in Table 3. The reflectance of ST-01 manufactured by Ishihara Industry Co., Ltd. as a reference is also shown in Table 3. Also, the NO of each sample _X The activity was measured in the same manner as in the above test examples, and the results are shown in Figures 9 to 11.

<tables><img file="TW548240B_D0003.tif" /></tables>

Example 10-1 (Relationship between washing and removal rate after heating (1))

3 g of the powder prepared in Example 6 was suspended in 100 ml of pure water and stirred for 1 hour using a magnet stirrer. The resulting solution was subjected to suction filtration. The sample remaining on the filter paper was again stirred in pure water and subjected to suction filtration. The filtration was repeated for 1 blow, 2 times, 3 times, 5 times or 7 times, and the obtained powder was placed in a drier set to 110 ° C for a day and night to dry, and the obtained sample was NO. _X The activity was measured in the same manner as in the above test examples, and the results are shown in Figures 12 to 14.

Further, the relationship between the number of times of washing and the pH value of the water separated from the material after washing and the chloride ion concentration is as shown in Fig. 15.

Example 10-2 (Relationship between washing and removal rate after heating (2)) 3 g of the powder prepared in Example 6 was suspended in 100 ml of pure water, and ultrasonic treatment was carried out for 10 minutes. The resulting solution was subjected to suction filtration. The sample remaining on the filter paper was again stirred in pure water and subjected to suction filtration. The filtration was repeated 0 times, once or 6 times, and the obtained powder was placed in a drier set to 110 ° C for a day and night to dry, and the obtained sample was NO. _X The activity was measured in the same manner as in the above test example, and the results are shown in Fig. 16.

Furthermore, the IR of each sample obtained is measured, the IR spectrum of the number of times of washing is divided by the value of the IR spectrum of the number of times of washing (A), and the IR spectrum of the number of times of washing is divided by the washing. The value (B) obtained by the IR spectrum of the net number of times 6 is shown in Fig. 17, respectively.

Example 11 (Review of water washing conditions before heating after hydrolysis)

The material of the present invention was obtained in the same manner as in Example 5 except that the stirring time of pure water was 10 minutes or 1 day. The NO of each sample obtained _X The activity was measured in the same manner as in the above test examples, and the results are shown in Table 4 below.

<tables><img file="TW548240B_D0004.tif" /></tables>

Example 12 (Preparation method (1) of visible light sensitive material derived from titanium sulfate) Production Example 1

Titanium (IV) sulfate solution, which is directly used as an aqueous solution of titanium (IV) sulfate (manufactured by Kanto Chemical Co., Ltd., trade name: titanium (IV) sulfate (Deer grade 1, containing titanium sulfate (IV) 24% by weight or more )) The stock solution. 50 g of this aqueous solution was mixed with a stirrer, and 58 ml of ammonia water (ammonia stock solution: water = 1:1) was added as soon as possible with a burette, and stirring was continued, and the solution began to become cloudy and the degree of condensation gradually increased. Further, ammonia water was added, and the pH was adjusted to 7 by a universal test paper. After 24 hours, it was filtered with a suction filter. The white matter adhering to the filter paper was stirred in ammonia water adjusted to pH 11 and filtered again, so as to be repeated 8 times, and then washed to obtain a white powder. The obtained powder was dried at 50 ° C to obtain a sample powder G. The BET surface area of the obtained hydrolyzate (sample powder G) was 308.7 m 2 /g.

Example 12-1

The sample powder G8 obtained in Production Example 1 was added to a crucible, and then transferred to an electric furnace, and calcined at 400 ° C for 60 minutes to obtain a bright yellow powder A6.3 g having a BET surface area of 89.4 m 2 /g.

Example 12-2

The sample powder G8 obtained in Production Example 1 was added to a crucible, and then transferred to an electric furnace, and calcined at 300 ° C for 60 minutes to obtain a bright yellow powder B6.5 g of a BET surface area of 101 m 2 /g.

Example 12-3

The sample powder G8 obtained in Production Example 1 was added to a crucible, and then transferred to an electric furnace, and calcined at 500 ° C for 60 minutes to obtain a pale yellow powder C6.2 g of a BET surface area of 52.6 m 2 /g.

Comparative Example 12-1

The sample powder G8 obtained in Production Example 1 was added to a crucible, and then transferred to an electric furnace, and calcined at a temperature of 100 ° C for 60 minutes to obtain a white powder D7.6 g of a BET surface area of 249 m 2 /g.

Comparative Example 12-2

The sample powder G8 obtained in Production Example 1 was added to a crucible, and then transferred to an electric furnace, and calcined at 200 ° C for 60 minutes to obtain a white powder E7.1 g of a BET surface area of 200 m 2 /g.

Comparative Example 12-3

A commercially available titanium oxide powder (ST-01 manufactured by Ishihara Sangyo Co., Ltd.) was used as the powder F. This powder F was a white powder having a BET surface area of 320 m 2 /g.

Characteristic evaluation

The properties of the powder obtained in Production Example 1, Examples 12-1 to 3, and Comparative Examples 12-1 to 3 were determined by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and oxidation activity of NO. And evaluation of the oxidation activity of isopropyl alcohol.

1. X-ray diffraction (XRD) of sample powder G obtained in Production Example 1, powders A, B and C obtained in Examples 12-1 to 3, and powders D, E and F obtained in Comparative Examples 12-1 to 3. The results of measurement by the X-ray diffraction analysis apparatus (manufactured by Rigaku Corporation, trade name: RINT-2000) with the change in the calcination temperature are shown in Fig. 18.

As shown in Fig. 18, the diffraction patterns of the powders B, D, E, and G could not be confirmed, and the powders A, C, and F were confirmed to be diffraction patterns of the sharp-cone crystals, and the powder A was compared with the powder C. There is a sharp-cone type titanium oxide which is formed by calcination and has an increased strength.

2. X-ray photoelectron spectroscopy (XPS) The sample powder G obtained in Production Example 1, the powder A obtained in Example 12-1, and the ratio of titanium to oxygen in the powder F obtained in Comparative Example 12-3, by X-ray photoelectron The spectroscopic analyzer (manufactured by Albuquerque Co., Ltd., trade name: Quantum 2000) was measured.

X-ray photoelectron spectroscopy was carried out under the following conditions.

Conditions for exciting X-ray generation: Electron rays having a beam diameter of 100 μm to 110 W are incident on an aluminum target, and monochromatic X-rays (Alkα1) thus generated are used as an excitation source.

Analytical field and mode: The analysis field is 1500 μm × 100 μm ψ, and the beam diameter is 100 μm ψ.

Take-out angle: 90-degree transfer energy: 187.85 eV (detected value), 23.50 eV (composite value) pitch width: 1.6 eV (detected value), 0.1 eV (composite value) obtained from X-ray photoelectron spectroscopy, which belongs to titanium 2p electron The peak area and the peak area of the 1s electron belonging to oxygen, the calculated ratio of the oxygen element to the titanium element (O/Ti) were as follows: sample powder G was 2.45, powder A was 2.28, and powder F was 2.40. Theoretically, the ratio of the oxygen element to the titanium element (O/Ti) of the titanium oxide powder (IV) (commercially available) is usually 2.00. However, the measured value of the commercially available powder F in this measurement is 2.40. The powder A having a smaller measured value should theoretically (actually) have an oxygen element to titanium element ratio (O/Ti) of at least 2.00 or less.

3.NO _X Measurement of activity removal The sample powder G obtained in Production Example 1, the powders A, B and C obtained in Examples 12-1 to 3 and the powders D, E and F obtained in Comparative Examples 12-1 to 3 were NO. _X The measurement of the removal activity was carried out in accordance with the method described in the above test examples. The results are shown in Table 5.

<tables><img file="TW548240B_D0005.tif" /></tables>

4. Measurement of Isopropanol Oxidation Activity Samples G obtained in Production Example 1, powders A, B and C obtained in Examples 12-1 to 3 and powders D, E and F obtained in Comparative Examples 12-1 to 3 were obtained. 0.2 g of each was applied to a glass piece (6 × 6 cm), which was then placed in a glass bell-type reaction vessel (volume: 1.9 liter). The light source is a 300W halogen lamp, and a filter (manufactured by Toshiba Corporation, trade name: IRA-25S, which removes light of a wavelength of 650 nm or more) and a filter (made by Toshiba Co., Ltd., trade name: L-42) , remove light of wavelengths below 420 nm). After sufficiently exhausting the inside of the system, 2-propanol was injected into the reaction vessel to make it a reaction gas having a concentration of 500 ppm. After the 2-propanol was brought to the adsorption equilibrium, light irradiation was performed for 2 hours. The reaction gas was analyzed by gas chromatography (FID), and the amount of increase in acetone concentration (acetone formation rate (ppm/min)) generated by oxidation was measured. The results are shown in Table 6.

<tables><img file="TW548240B_D0006.tif" /></tables>

As is clear from Table 6, the powder A obtained in Example 12-1 had a large acetone formation rate (ppm/min) and had high acetone formation characteristics (photocatalytic function) in the oxidation of 2-propanol by visible light irradiation. On the other hand, in the powders G, E, and F, since almost no increase in acetone was observed, it was found that the photocatalytic function was not obtained.

4. The powders D, E and F obtained by observing the sample powder G obtained in Production Example 1, the powders A, B and C obtained in Examples 12-1 to 3 and the comparative examples 12-1 to 3 were measured by color analysis. The degree of light absorption was measured by a color analyzer (manufactured by Tokyo Electrochromatography Co., Ltd., trade name: TC-1800) to reflect the reflectance when irradiating light of a wavelength in the visible light region. The results are shown in Fig. 19. It can be seen from Fig. 19 that the powders A, B, and C are colored by absorption of a large amount of visible light, and have visible light activity (photocatalytic function). Further, the reflectance of each powder (the reflectance under light irradiation at a wavelength of 450 nm when the reflectance under irradiation of light having a wavelength of 600 nm was set to 1) is shown in Table 7.

<tables><img file="TW548240B_D0007.tif" /></tables>

The ESR spectrum of Powder A obtained in Example 12-1 was measured. The measurement was carried out in a vacuum (0.1 Torr) and at a temperature of 77K. The measurement conditions were the same as in Example 1.

Fig. 20 (setting temperature: 77 K) indicates an ESR spectrum measured by light removal of light of 420 nm or less by a filter (L-42), and a 500 W high pressure mercury lamp was used. Furthermore, although the ESR spectrum in the dark is also measured, the signal is substantially invisible.

From the spectrum shown in Fig. 20, the main signal with a g value of 2.004 to 2.007 and two sub-signals with a g value of 1.985 to 1.986 and 2.024 can be observed.

Furthermore, in the case where the white hydrolyzate is dried at 50 ° C, the main signal with a g value of 2.004 to 2.07 and two sub-signals with a g value of 1.985 to 1.986 and 2.024 cannot be observed under any of the ESR measurement conditions. To.

Example 13 (Preparation method of visible light sensitive material derived from titanium sulfate (2))

50 g of a 24% titanium sulfate solution (manufactured by Kanto Chemical Co., Ltd., Deer 1) was added to 400 ml of distilled water, and stirred with a magnet stirrer. Among them, concentrated ammonia water (28%, manufactured by Kanto Chemical Co., Ltd.) was added to carry out a neutralization reaction. After the neutralization reaction, the pH was adjusted to 7 and stirred for 15 minutes. At this time, since the agitator often became unable to rotate, 200 ml of distilled water was added. After 15 minutes, the stirring was stopped and then temporarily placed, and the supernatant was discarded. The filtration was carried out by suction filtration (Nutsche), at which time it was washed with 2 liters of ammonia (5:95). Such a work is a method of adding ammonia water when a filter cake is formed on the filter paper. Then, the obtained product was dried at 60 ° C for 24 hours, and further calcined at 400 ° C for 1 hour to obtain a visible light sensitive material of the present invention.

NO of the material obtained _X The removal activity was measured by the same method as the above test example, and the results are shown in Table 8.

<tables><img file="TW548240B_D0008.tif" /></tables>

The ESR spectrum of the obtained material was measured. The measurement was carried out in a vacuum (0.1 Torr) and at a temperature of 77K. The measurement conditions were the same as in Example 1.

Fig. 21 (setting temperature: 77 K) indicates an ESR spectrum measured by light removal of light of 420 nm or less by a filter (L-42), and a 500 W high pressure mercury lamp was used.

From the spectrum shown in Fig. 21, the main signal with a g value of 2.004 to 2.07 and two sub-signals with a g value of 1.985 to 1.986 and 2.024 can be observed.

Furthermore, in the case where the white hydrolyzate is dried at 50 ° C, the main signal of g value of 2.004 to 2.07 and the two sub-signals of g values of 1.985 to 1.986 and 2.024 are not observed under any of the ESR measurement conditions. .

Example 14 (Preparation method from alkoxide)

While stirring, 30 g of titanium isopropoxide was slowly added to 200 g of pure water (the molar ratio of water to titanium isopropoxide was about 10:1). After the obtained solution was stirred for about 30 minutes, the precipitate (water-decomposed product) was collected by filtration, and the precipitate (water-decomposed product) was suspended in pure water, filtered after stirring for 1 day, and then dried at 110 ° C, and further Calcined at 400 ° C for 1 hour. The obtained white powder was used as sample A.

In addition to the operation of suspending the precipitate (hydrolysis product) in pure water and stirring for 1 day, the precipitate (hydrolysis product) was suspended in ammonia water (concentration of ammonia: 6%) and stirred for 1 day instead of Further, the obtained yellow powder was used as the sample B in the same manner as the above operation.

Sample A and B NO _X The activity was removed in the same manner as in the above test method. The results are shown in Table 9 below.

<tables><img file="TW548240B_D0009.tif" /></tables>

As is clear from the results of Table 9, a material composed of titanium oxide having visible light sensitivity can be obtained by heat-treating titanium oxide (titanium hydrolyzate) in the presence of ammonia.

The ESR spectrum of the material was determined. The measurement was carried out in a vacuum (0.1 Torr) and at a temperature of 77K. The measurement conditions were the same as in Example 1.

Fig. 22 (setting temperature: 77 K) indicates an ESR spectrum measured by light removal of light of 420 nm or less by a filter (L-42), and a 500 W high pressure mercury lamp was used.

From the spectrum shown in Fig. 22, the main signal with a g value of 2.004 to 2.07 and two sub-signals with a g value of 1.985 to 1.986 and 2.024 can be observed.

Furthermore, in the case where the white hydrolyzate is dried at 50 ° C, the main signal with a g value of 2.004 to 2.07 and two sub-signals with a g value of 1.985 to 1.986 and 2.024 cannot be observed under any of the ESR measurement conditions. To.

Example 15 (Preparation method from titanium sulfate plus water decomposition product)

The hydrolyzed product obtained by substituting the aqueous ammonia in Example 12 with an aqueous sodium hydroxide solution was suspended in pure water, stirred for 1 day, filtered, then dried at 110 ° C, and further calcined at 400 ° C for 1 hour. The obtained white powder was used as sample C.

In addition to the operation of suspending the precipitate (hydrolysis product) in pure water and stirring for 1 day, the precipitate (hydrolysis product) was suspended in ammonia water (concentration of ammonia: 6%) and stirred for 1 day instead of Further, the obtained yellow powder was used as the sample D in the same manner as the above operation.

Samples C and D of NO _X When the activity was measured in the same manner as in the above test method, as in the case of the samples A and B in Example 14, the sample C calcined at 400 ° C for 1 hour in the absence of ammonia had no visible light sensitivity, and was ammonia. The sample D which was calcined at 400 ° C for 1 hour in existence was visually sensitive.

Reference example

In the titanium oxide of the visible light sensitive material of the present invention obtained in Examples 7, 12-1 and 13, the molar ratio of oxygen to titanium was measured by X-ray photoelectron spectroscopy (ESCA). As a control sample, a grade 1 titanium dioxide was prepared using Wako Pure Chemical.

The measurement by X-ray photoelectron spectroscopy (ESCA) was carried out in the same manner as the X-ray photoelectron spectroscopy shown in the evaluation of the characteristics of Example 12. The results are shown in Table 10.

<tables><img file="TW548240B_D0010.tif" /></tables>

Industrial use possibilities

The visible light sensitive material of the present invention can be used as a photocatalyst, a photosensor, a photocell material, a light antifouling material, a photohydrophilic material, and a photobacterial material.

According to the present invention, a novel photosensitive material sensitive to visible light can be provided, and the material can be inexpensively manufactured by using a wet method. In the present invention, titanium oxide having visible light sensitivity which can be used as a photocatalyst can be easily and inexpensively produced by using an existing device which is used by a wet method such as a sulfuric acid method.