Method for preparing highly disperse supported noble metal nanoparticles

A kind of preparation method of highly dispersed load type precious metal nanoparticlesTechnical field

[0001] The present invention belongs to the field of inorganic nanomaterials, and particularly relates to a method for preparing highly dispersed supported noble metal nanoparticles.

Background technique

[0002] Metal nanoparticles are widely used in the fields of optical materials, separation, catalysis, etc. due to their large specific surface area and special surface properties. Especially in the field of catalysis, it has more defects and active sites compared with bulk metals, and therefore has higher catalytic activity, which has attracted the attention of researchers.

[0003] In chemical production, transition metals Pd, Ag, Au and other elements are commonly used catalysts, which have shown good performance for hydrogenation, oxidation, dehydrogenation, and hydrogenation decomposition reactions. The preparation of highly dispersed supported metal nanoparticles is one of the research hotspots in the field of heterogeneous catalysis

[0004] However, it is precisely because the nanoparticles have high specific surface energy that they are prone to agglomeration during use, thereby reducing the catalytic activity. Therefore, maintaining good dispersion is a key issue in the use of metal nanoparticles. The current preparation methods of supported metal nanoparticles mainly include sonochemical method I], microwave radiation method ", immersion method E, co-precipitation method, chemical vapor deposition, microemulsion method Z23]. However, most of these methods require more High temperature in order to fully reduce the dissolved metal salt or need to use stabilizers (such as polymers or ligands) to avoid agglomeration of metal nanoparticles. The stabilizers are often difficult to remove, and the removal process will reduce the activity of metal nanoparticles Etc. Therefore, it is extremely necessary to develop a new type of preparation method of loaded nanoparticles, which should avoid the use of toxic reagents as much as possible, with simple steps and lower operating temperature.

Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing highly dispersed supported noble metal nanoparticles to solve the current problems of complex preparation process of noble metal nanoparticles, high pollution, and high energy consumption.

[0006] A method for preparing highly dispersed supported noble metal nanoparticles is carried out according to the following steps:

[0007] (1) Weigh the precious metal compound, dissolve it in absolute ethanol, and configure it into a precious metal solution of 5-700 ppm;

[0008] (2) Weigh 1-3g of porous glass microspheres with a core-shell structure particle size of 95-105 μm that have been etched by subcritical water, and mix them with the precious metal solution, in a 15-60° constant temperature water bath After stirring for 0.1-30 h, filter out the porous glass microspheres, and wash 2-10 times with absolute ethanol to remove ions on the surface of the porous glass microspheres;

[0009] (3) The washed porous glass microspheres are placed in a 60-100°C oven and dried to obtain highly dispersed loaded nanoparticles.

[0010] The noble metal compound is chlorinated rake, silver nitrate or gold chloride.

[0011] The temperature of the subcritical water etching is 300 °C, and the pressure is 10 MPa.

[0012] The subcritical water refers to water that is heated to above the boiling point (100°) and below the critical point (374°), and remains liquid due to the system pressure being controlled.

[0013] The present invention takes the porous glass microspheres with core-shell structure etched by subcritical water as the carrier. Through ion exchange technology, the target metal ion acts on the carrier in the form of chemical bonds, and the force between the carrier Strong, effectively avoid

The agglomeration of metal ions is avoided, the uniformity, high dispersion and stability of the target metal loaded on the hollow glass microspheres are realized, and a larger specific surface area is obtained under the same loading amount, and a nano-metal particle loaded catalyst.

[0014] When the ion exchange technology of the present invention loads metal ions, the metal ions and the sodium, calcium, magnesium and other elements in the glass microspheres undergo ion exchange, that is, the following reactions occur:

[0015] = Si-O-Na (Mg²⁺, Ca²⁺) +Ag⁺ (Pd²⁺, Au³*) f three Si-O-Ag (Pd, Au) +Na⁺ (Mg²⁺, Ca²⁺)

[0016] It can be seen that the target metal acts on the porous glass microspheres in the form of a chemical bond, and the chemical bond has a strong force, which can effectively avoid the agglomeration between metal ions, thereby ensuring the uniformity and high loading of the target metal. Dispersibility and stability, and then the solvent ethanol reduces metal ions at room temperature to obtain metal nanoparticles.

[0017] The beneficial effects of the present invention: the preparation process of the present invention is simple and easy to operate, avoiding organic pollution, the whole process is carried out at room temperature, low energy consumption, suitable for industrialized large-scale production; the loading of precious metals Pd, Ag and Au is realized Uniformity, high dispersion and stability; carrier has excellent thermal and chemical stability, suitable structure (core-shell structure); easy to recycle, no pollution.

Description of the drawings

[0018] FIG. 1 is a schematic diagram of a method for preparing highly dispersed supported noble metal nanoparticles of the present invention;

[0019] FIG. 2 is a TEM photograph of the precious metal nanoparticles of the present invention;

[0020] In the figure, (a), (b): Pd nanoparticles; (c), (d): Ag nanoparticles; (e), (f): Au nanoparticles.

Detailed ways

[0021] The present invention will be further described below with reference to the drawings and specific embodiments.

[0022] The following embodiment of the method for preparing highly dispersed supported noble metal nanoparticles is shown in FIG. 1.

Example 1

[0024] Take 1.5 g of porous glass microspheres with a core-shell structure particle size of 95-105 μm and an initial concentration of 100 ppm of chlorine after subcritical water etching (temperature of 300 ° C, pressure of 10 MPa) The chemical rake-ethanol solution was mixed and stirred in a 20°C constant temperature water bath for 24 hours. The color of porous glass microspheres gradually changed from white to gray. After the adsorption reached equilibrium, take out the glass microspheres loaded with nano-targets and wash 5 times with absolute ethanol to remove the ions on the surface of the material. Then, it is placed in an oven and dried to obtain supported target nanoparticles. Figure 2 (a) and (b) are transmission photographs of the sample obtained in this example.

Example 2

[0026] Take 3.0 g of porous glass microspheres with a core-shell structure particle size of 95-105 μm and silver nitrate with an initial concentration of 600 ppm after subcritical water etching (temperature of 300° C., pressure of 10 MPa) -The ethanol solution was mixed and stirred in a 30° constant temperature water bath for 30 hours. The color of the glass microspheres gradually changed from white to gray. After the adsorption reached equilibrium, the glass microspheres loaded with nano-silver were taken out and washed with absolute ethanol for 4 times to remove ions on the surface of the material. Then, it is placed in an oven and dried to obtain supported silver nanoparticles. Figures 2 (c) and (d) are transmission photographs of the samples obtained in this example.

Example 3

[0028] Take 1.0 g of porous glass microspheres with a core-shell structure particle size of 95-105 μm and an initial concentration of 50 ppm chlorine after subcritical water etching (temperature of 300 ° C, pressure of 10 MPa) The gold-ethanol solution was mixed and stirred in a 50°C constant temperature water bath for 5 hours. The color of glass microspheres gradually changed from white to pink. After the adsorption reached equilibrium, the glass microspheres loaded with nano-targets were taken out and washed with absolute ethanol for 10 times to remove ions on the surface of the material. Then, it is placed in an oven and dried to obtain supported gold nanoparticles. Figures 2(e) and (f) are transmission photographs of the samples obtained in this example.

[0029] References:

[0030] [1] Yiwen Sun, Yujun Wang, Yangcheng Lu, Tao Wang, and Guangsheng Luo.

Subcritical water treatment :asimple methord to prepare porous glass with a core-shell structure. Journal of the American Ceramic Society,2008,91,103-109.

[0031] [2] Chun Shen, Yujun Wang, Jianhong Xu, Yangcheng Lu, Guangsheng Luo.

Preparation and ion exchangeproperties of egg-shell glass beads with different morphologies. Particuology, 2011, in press.

[0032] [3] Basnayake, R.; Li, B R.; Katar, S.; Zhou, W.; Rivera, H.; Smotkin, ES; Casadonte, DJ; Korzeniewski, C. Langmuir 2006, 22, 10446 .

[0033] [4] Nagao, D.; Shimazaki, Y.; Saeki, S.; Kobayashi, Y.; Konno, M. Colloids Surf., A 2007,302,326.

[0034] [5] Perkas, N.; Zhong, B Y.; Grindblat, J.; Gedanken, A. Catal. Lett. 2008, 120, 19.

[0035] [6] Campelo, JM; Conesa, TD; Gracia, MJ; Jurado, MJ; Luque, R.;

Marinas, JM; Romero, AA Green Chem. 2008,10,853.

[0036] [7] Galletti, AMR; Antonetti, C.; Venezia, AM; Giambastiani, G. Appl. Catal., A 2010,386,124.

[0037] [8] Zhang, BS; Ni, XJ; Zhang, W.; Shao, LD; Zhang, Q.; Girgsdies, F.;

Liang, CH ;Schlogl, R. ;Su, DS Chem. Comm. 2011,47,10716.

[0038] [9] Cano, M.; Benito, A.; Maser, WK; Urriolabeitia, Ε. P. Carbon 2011, 49, 652.

[0039] [10] Paschos, 0.; Simonov, AN; Bobrovskaya, AN; Hantel, M.; Rzepka, M.; Dotzauer, P.; Popov, AN; Simonov, PA; Parmon, VN; Stimming, U. Electrochem. Commun. 2010, 12, 1490.

[0040] [ll] Escamil la-Perea, L.; Nava, R.; Pawelec, B.; Rosmaninho, MG; Peza-Ledesma, CL; Fierro, JLG Appl. Catal., A 2010, 381,42.

[0041] [12] Park, JY; Lee, YJ; Karandikar, PR; Jun, KW; Bae, JW; Ha,

KSJ Mol. Catal. A:Chem. 2011,34,153.

[0042] [13] Carabineiro, SAC; Bogdanchikova, N.; Avalos-Borja, M.; Pestryakov, A.; Tavares, Ρ. B. Figueiredo, JL Nano Res. 2011, 4, 180.

[0043] [14] Silva, JMDS; Strauss, M.; Maroneze, CM; Souza, ER; Gushikem, Y.;

Sigoli, FA; Mazali, I. 0. J. Mater. Chem. 2011,21,15678.

[0044] [15] Gupta, K.; Bhattacharya, S.; Chattopadhyay, D.; Mukhopadhyay, A.;

Biswas, H.; Dutta, J.; Ray, NR; Ghosh, UC; Chem. Eng. J. 2011,172, 219.

[0045] [16] Senapati, KK; Borgohain, C.; Phukan, PJ Mol. Catal. A: Chem. 2011, 339,

24.

[0046] [17] Hisada, D.; Fujiwara, Y.; Sato, H. Jimbo, M.; Kobayashi, T.; Hata,

KJ Magn. Magn. Mater. 2011, 323, 3184.

[0047] [18] Zhang, JF Tingu, R.; Goto, TJ Eur. Ceram. Soc. 2011, 31, 2083.

[0048] [19] Zhao, Ζ. K.; Lin, XL; Jin, RH Dai, YT; Wang, GR Catal. Commun. 2011,

12,1448.

[0049] [20] Dziembaj, R.; Molenda, M.; Chmielarz, L.; Zaitz, Μ. M.; Piwowarska, Z.; Rafalska-Lasocha, A. Catal. Today 2011, 169, 112.

[0050] [21] Li, LR; Huang, Μ. H.; Liu, JJ; Guo, YL; J. Power Sources 2011,169,

1090.

[0051] [22] Lee, E.; Manthiram, AJ Phys. Chem. C 2010, 114, 21833.

[0052] [23] Liang, CH; Han, JG; Shen, Κ. H.; Wang, LG; Zhao, DF; Freeman,

HS Chem. Eng. J. 2010,165, 709.