Preparation method of yellow TiO2 photocatalytic material capable of absorbing visible light

A kind of preparation method of yellow T i 02 photocatalytic material with visible light absorption performanceTechnical field

[0001] The present invention belongs to the technical field of preparation of photocatalytic materials, and relates to a method for preparing yellow TiO 2 with visible light absorption properties.

Background technique

[0002] Energy and environmental issues are two major issues facing the sustainable development of human society. Photocatalytic technology has potential application prospects in solving environmental pollution and energy shortages. Since the Japanese scholar Fujishima and others first discovered the phenomenon that TiOz single crystal electrode can decompose water under the action of ultraviolet light in 1972, photocatalytic technology has attracted widespread attention. At present, many photocatalytic materials have been reported to have good photocatalytic properties, such as TiO2, ZnO, CdS, Fe2O3, BiOC^.

[0003] TiOz has the properties of non-toxicity, good stability, low cost, and high UV photocatalytic activity, making it the most widely studied and most widely used photocatalytic material, and preliminary industrial production has been realized. In recent decades, scientific researchers at home and abroad have conducted a lot of research on TiO2-based photocatalysts and have made great progress, but there are still problems. TiO2 is a wide band gap semiconductor (band gap of 3.2eV), Therefore, TiO2 can only use the ultraviolet light that accounts for about 4% of the sunlight, which greatly reduces the utilization of sunlight.

[0004] Expanding the light absorption of TiOz and realizing the total light absorption and utilization of sunlight by TiO2 is an important challenge in the practical application of TiOz photocatalytic materials. So far, various methods have been proposed to expand the light absorption of Ti02, such as: metal or non-metal doped TiO2, TiO2 self-doping (Ti3+), dye-sensitized TiO2, TiO2-based organic titanium light Catalytic materials and so on. Among them, the TiO2-based organic titanium photocatalytic material has attracted wide attention of researchers and is considered to be a very promising method to realize the visible light absorption of TiO2. However, there are few reports on the synthetic methods and mechanism of action in this regard. How to discover and provide new simple and efficient synthetic methods is still the focus and difficulty of the research in this field.

Summary of the invention

[0005] In view of the current research status of TiO2 photocatalytic materials in the prior art and the above-mentioned problems, the inventors, after experimental research, disclose a method for preparing a yellow TiO2 photocatalytic material with visible light absorption, using colorless organic molecular ethylene glycol Formaldehyde synthesizes yellow TiO2 through a one-step hydrothermal method. The absorption band edge of this yellow TiO2 photocatalytic material extends from 406nm to 605nm. The material shows good catalytic performance for the degradation of organic pollutants by visible light. Photocatalytic materials provide a new way.

[0006] One of the objectives of the present invention is to provide a method for preparing a yellow TiOz photocatalytic material with visible light absorption.

[0007] The second object of the present invention is to provide a yellow TiOz photocatalytic material with visible light absorption.

[0008] Another object of the present invention is to provide the application of the obtained yellow TiOz photocatalytic material with visible light absorption.

[0009] In order to achieve the above-mentioned purpose of the invention, the present invention relates to the following technical solutions:

[0010] First of all, the present invention discloses a method for preparing a yellow TiOz photocatalytic material with visible light absorption, the method comprising:

[0011] The titanium precursor is added to the water/organic two-phase system, and the hydrothermal synthesis reaction is carried out to prepare a visible

Light-absorbing yellow Ti02 photocatalytic material;

[0012] The precursor of the titanium is tetrabutyl titanate;

[0013] The water/organic two-phase system is a mixed system of water, ethanol and ethylene glycol formaldehyde (methoxyethanol).

[0014] The present invention uses a hydrothermal synthesis reaction between a titanium precursor and a water/organic two-phase system to prepare a TiO2 photocatalytic material with visible light absorption, and provides a new method for preparing a TiO2 photocatalytic material.

[0015] In a preferred embodiment, the molar ratio of ethanol, ethylene glycol formaldehyde and water in the water/organic two-phase system of the present invention is (10-20): (5T5):1. Different alcohols and alcohol substitution amounts have an effect on the purity and morphology of the synthesized TiO2 photocatalytic material of the present invention. Experiments have shown that the synthesized TiO2 photocatalytic material has the best performance under the conditions of this preferred ratio range. It is yellow TiOz, which is the most effective catalyst material. The absorption band edge extends from 406 nm to 605 nm, and the band gap is 2. leV. More preferably, the molar ratio of ethanol, ethylene glycol formaldehyde and water is 15:10:1.

[0016] In a preferred embodiment, the volume ratio of the tetrabutyl titanate of the present invention to the water/organic two-phase system is 1:45-55.

[0017] In a more preferred embodiment, the method for preparing the TiOz photocatalytic material with visible light absorption of the present invention, the steps are as follows:

[0018] (1) Mix ethanol and ethylene glycol formaldehyde in a certain ratio, and fully stir for 3 Tomin;

[0019] (2) Drop a certain amount of deionized water into the above-mentioned mixed solution of ethanol and ethylene glycol formaldehyde, and fully stir for 5 to 20 minutes;

[0020] (3) Drop a certain amount of tetrabutyl titanate into the above-mentioned mixed solution, and stir for 10-30 min to make it evenly mixed;

[002U (4) Transfer the mixed solution to a reaction kettle lined with polytetrafluoroethylene, react for 1224h in an oven at 160-200C, cool naturally, wash, and dry to obtain the product;

[0022] The molar ratio of the amount of ethanol, ethylene glycol formaldehyde and water is 15:10:1;

[0023] The volume ratio of tetrabutyl titanate to water is 1: (1.5-2).

[0024] Secondly, the present invention provides a yellow TiOz photocatalytic material with visible light absorption prepared by the above preparation method.

[0025] In addition, the present invention provides the application of the yellow TiOz photocatalytic material in the degradation of organic pollutants.

[0026] The present invention has the following beneficial effects:

[0027] (1) The preparation method of the present invention involves a wide range of sources of raw materials, reducing energy waste and environmental pollution, and the preparation cost is low;

[0028] (2) The method for synthesizing the TiOz photocatalytic material of the present invention is simple and can be prepared with only one step of water heating;

[0029] (3) The yellow TiOz photocatalytic material prepared by the present invention has an absorption band edge extended from 406 nm to 605 nm, and has good catalytic performance for visible light degradation of organic pollutants;

[0030] (4) The action mechanism of the TiOz photocatalyst with visible light absorption prepared by the present invention is the effect of hydrogen bonding, and this mechanism provides a new way for preparing the TiOz photocatalyst with visible light absorption.

Description of the drawings

[0031] FIG. 1 is an X-ray diagram of the product of Example 1 of the present invention

[0032] FIG. 2 is a SEM image of the product of Example 1 of the present invention

[0033] Figure 3 Photocatalytic degradation of pollutant organic matter activity

[0034] Figure 4 Infrared spectrogram of the product obtained in Example 1

Detailed ways:

[0035] Example 1 Preparation of yellow TiO2 photocatalytic material (MES-TiOz)

[0036] Measure 30ml of ethanol and 20ml of ethylene glycol formaldehyde respectively and add them to a 100ml polytetrafluoroethylene lined autoclave, constantly stirring to make the two solutions fully mixed; measure 2ml of deionized water into the above mix Solution, continue to stir to make the mixed solution form a uniform solution, and then slowly add 1ml of tetrabutyl titanate to the above mixed solution, and continue to stir for 20 minutes. Finally, the reaction kettle was placed in a 180C oven to react for 24 hours, cooled naturally at room temperature, filtered with suction, and the sample was washed three times with deionized water and absolute ethanol, and dried under vacuum for 6 hours to obtain the product yellow TiOz.

[0037] Example 2 Preparation of yellow TiO2 photocatalytic material

[0038] Measure 20.0ml ethanol and 13.3ml ethylene glycol formaldehyde respectively and add them to a 100ml polytetrafluoroethylene-lined high-pressure reactor, continuously stirring to make the two solutions fully mixed; measure 1ml deionized water into the The above-mentioned mixed solution is continuously stirred to form a uniform solution, and then 0.67 ml of tetrabutyl titanate is slowly added dropwise to the above-mentioned mixed solution, and stirring is continued for 20 minutes. Finally, the reaction kettle was placed in a 180C oven to react for 18 hours, cooled naturally at room temperature, filtered with suction, and the sample was washed 3 times with deionized water and absolute ethanol, and dried in vacuum for 6 hours to obtain the product yellow TiOz.

[0039] Example 3 Characterization of Yellow TiO2 Photocatalytic Material

[0040] The Bruker AXS D8 X-ray diffractometer was used for phase analysis of the sample, and Cu ΚαΧ-ray was used as the radiation source. Figure 1 is the X-ray diffraction pattern of the product obtained in Example 1. It can be seen from Figure 1 that the diffraction peaks of the product match the standard card of anatase Ti02 (JCPDS file no.21T272), indicating that the product is anatase Ti02; The SEM image of the product of Example 1 is shown in FIG. 2.

[0041] Example 4 Activity Test of Yellow TiOz Photocatalytic Material

[0042] The photocatalytic material of the present invention was tested for the activity of composite photocatalysis according to the following method:

[0043] The organic dye Rhodamine B was selected to evaluate the visible light photocatalytic performance of the prepared samples, and the light source was a 300W debt lamp (with an ultraviolet filter). The entire process of visible light photocatalysis is carried out in a glass beaker (cross section 30cm2, height 5cm). Disperse 0.1 g of the photocatalytic material into 100 mL of Rhodamine B aqueous solution (20 mg/L). Before lighting, magnetically stir for 2h under dark conditions to make the solution reach adsorption/desorption equilibrium, then light, take 5mL samples every 30min, centrifuge to take the supernatant, and measure its absorbance with a UV-Vis spectrophotometer. The photocatalytic activity effect is shown in Figure 3.

[0044] Example 5 ΊΊ02 photocatalyst mechanism study

[0045] Fourier transform infrared spectrometer was used to analyze the infrared spectrum of the sample. Figure 4 is the infrared spectrum of the product obtained in Example 1. It can be seen from Figure 4 that the -OH vibration peak of MES-TiOz has shifted to a low wave number (from 3285cmT to 3215cmT) relative to the -OH vibration peak of pure TiOz. This phenomenon indicates the formation of hydrogen bonds. In order to explore the role of hydrogen bonds, the inventors further modeled the structure of MES-TiOz and performed first-principles calculations. Through calculations, the following results were obtained: The visible light absorption of MES-TiOz originates from hydrogen bonds. To the electronic transition between Ti atoms in TiOz. At the same time, holes can be transported through 0-50, resulting in effective separation of electrons and holes. Therefore, the inventor believes that the good visible light absorption and effective separation of electrons and holes caused by this hydrogen bond are the reasons why yellow titanium dioxide has effective visible light performance.

[0046] Although the above-mentioned embodiments give a detailed description of the present invention, they are only a part of the embodiments of the present invention, rather than all of the embodiments. People can also obtain other embodiments according to this embodiment without being creative. These embodiments all belong to the protection scope of the present invention.