CN109967115B - Supported bimetallic carbon-silicon composite catalyst and preparation method and application thereof - Google Patents
Supported bimetallic carbon-silicon composite catalyst and preparation method and application thereof Download PDFInfo
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Abstract
A supported bimetallic carbon-silicon composite catalyst and a preparation method and application thereof are provided, wherein the preparation method of the supported bimetallic carbon-silicon composite catalyst comprises the following steps: (1) crushing rice hulls; (2) treating rice hull with acid; (3) carrying out pyrolysis and carbonization on rice hulls; (4) functionalization; (5) carrying metal. The method is based on the concept of green chemistry, utilizes the biomass resource rice hulls as the raw materials of the catalyst carrier, has the advantages of easily obtained and cheap raw materials, does not relate to high temperature and high pressure in the preparation process, has mild reaction conditions and low requirement on equipment, and greatly reduces the energy consumption; the preparation process of the catalyst is green and environment-friendly, has low cost and can be repeatedly utilized; (2) the prepared supported bimetallic carbon-silicon composite catalyst is applied to the selective oxidation catalytic reaction of benzyl alcohol without solvent, does not relate to other organic solvents, and is green and pollution-free; the catalyst is easy to recover, can be repeatedly used and has high catalytic activity.
Description
Technical Field
The invention relates to a carbon-silicon composite catalyst, a preparation method and application thereof, in particular to a loaded bimetallic carbon-silicon composite catalyst, and a preparation method and application thereof.
Background
Rice hulls, an inexpensive agricultural residue consisting of 20% ash, 38% cellulose, 22% lignin, 18% pentoses, and 2% other organic constituents, are produced in annual quantities of up to 1.4 million tons and are typically burned or discarded. The production and consumption of fossil fuels and human activities such as agricultural and industrial activities have led to an increase in the concentration of greenhouse gases in the atmosphere. The shortage of fossil fuels and environmental concerns about energy sources have created an urgent need to develop clean renewable energy sources. Therefore, many countries have proposed plans to reduce carbon dioxide emissions and fossil energy consumption. Biomass is one of the most promising energy carriers, and plays an important role in environmentally friendly energy utilization. Therefore, the preparation of high value-added products, such as recyclable catalysts, by using rice hulls is of great significance.
However, the carbon sources are currently limited to non-green economical phenolic resins and their derivatives, pitches, polyamines, etc.; the assembly method is limited to the cooperative assembly of the structure directing agent, the carbon source and the silicon source.
CN 104415765A discloses a preparation method of a Ru-Ni bi-metal based ordered mesoporous carbon catalyst, which comprises the steps of taking CTAB as a template, TEOS as a silicon source, 8-hydroxyquinoline modified chitosan as a carbon source, and nickel salt and ruthenium salt as metal precursors, reacting at room temperature in an ethanol-water medium under an alkaline condition, and carrying out hydrothermal treatment to obtain a cubic mesoscopic compound with uniformly dispersed metal chitosan complexes; then directly carbonizing at high temperature to remove the template, carbonizing chitosan and reducing Ru and Ni metal ions, and finally removing silicon dioxide in situ to obtain the ordered mesoporous carbon loaded Ru-Ni bimetallic nano catalyst. According to the method, CTAB is used as a template, TEOS is used as a silicon source, 8-hydroxyquinoline modified chitosan is used as a carbon source, the method cannot be repeatedly utilized, the method belongs to a non-renewable resource, a large amount of organic solvent needs to be consumed, the method does not conform to the concept of green chemistry, the process is complex, the requirements on instruments and equipment are high, and the cost is high.
CN 106362739A discloses a mesoporous carbon-silicon dioxide complex supported nano gold catalyst and a preparation method thereof, the catalyst has an ordered two-dimensional hexagonal mesostructure, and the specific surface area is 400-900 m 2 The pore diameter is 3.0-7.0 nm, the percentage content of the gold nanoparticles is 1-5 wt%, and the particle diameter is 2-10 nm; during preparation, the surfactant is dissolved in an organic solvent to prepare a solution A; adding a silicon source into an acid solution, and carrying out prehydrolysis to obtain a solution B; mixing the solution A and the solution B, uniformly stirring, adding a carbon source, volatilizing an organic solvent to obtain a solid intermediate, performing low-temperature thermosetting reaction, and performing reflux extraction by using an acidic solution after the reaction is finished to remove a surfactant to obtain a carrier precursor; mixing the carrier precursor with a gold source, calcining at high temperature, carbonizing and reducing. The method has the advantages of high cost of carbon and silicon sources, complex process, high energy consumption and no environmental protection, and needs high-temperature calcination.
Benzaldehyde is one of the most valuable aromatic aldehydes due to its use in the fragrance, pharmaceutical, cosmetic, dye and agrochemical industries. Commercially, it is produced mainly by a toluene chlorination/hydrolysis process, while generating large amounts of toxic acidic waste, and causing corrosion of equipment and expensive separation processes.
Disclosure of Invention
The technical problem to be solved by the invention is to overcome the defects in the prior art and provide a raw material which is easy to obtain and low in cost. The preparation process is green and environment-friendly, the cost is low, and the supported bimetallic carbon-silicon composite catalyst can be recycled, and the preparation method and the application thereof.
The technical scheme adopted by the invention for solving the technical problem is as follows: a preparation method of a loaded bimetallic carbon-silicon composite catalyst is prepared according to the following steps:
(1) crushing rice hulls: washing rice hulls with water to remove impurities, drying, crushing and sieving to obtain rice hull powder;
(2) treating rice husk acid: adding a hydrochloric acid solution into the rice hull powder, placing the mixture into a reactor for refluxing, washing the obtained product with water, and drying to obtain acid-treated rice hull powder;
(3) rice hull pyrolysis and carbonization: placing the rice hull powder subjected to acid treatment in a quartz tube, and placing the quartz tube in a tube furnace for pyrolysis carbonization to obtain a carbon-silicon composite carrier;
(4) functionalization: dissolving the carbon-silicon composite carrier in toluene in a container, and then adding 3-aminopropyltriethoxysilane for surface functionalization to obtain a functionalized carbon-silicon composite carrier;
(5) carrying out metal loading: dispersing the functionalized carbon-silicon composite carrier in an aqueous solution containing chloroauric acid and palladium chloride, adjusting the pH value of the solution to be neutral, heating and stirring the obtained mixture, and reducing the mixture by using sodium borohydride to obtain the loaded bimetallic carbon-silicon composite catalyst.
Further, in the step (1), the grain size of the rice hull powder is less than or equal to 90 nm; the drying was carried out overnight in an oven at 90 ℃.
Further, in the step (2), the rice hull powder and a hydrochloric acid solution with the mass fraction of 5-20% (preferably 10%) are placed in a reaction kettle according to the solid-to-liquid ratio of 1: 8-15 (preferably 1: 10) to be refluxed for 1-3 hours (preferably 2 hours).
Further, in the step (3) of the preparation method, the carbonization temperature is 500 to 900 ℃ (preferably 600 to 800 ℃, and more preferably 700 ℃).
Further, in the step (4), dissolving the carbon-silicon composite carrier in toluene according to a solid-to-liquid ratio of 1: 8-15 (preferably 1: 9), and adding 3-aminopropyltriethoxysilane for surface functionalization, wherein the addition amount of the 3-aminopropyltriethoxysilane is 1/3-3 times of the mass of the carbon-silicon composite carrier; refluxing for 24-48 h (preferably 48 h) at 100-120 ℃ (preferably 110 ℃), centrifugally separating, washing with methanol, and vacuum drying to obtain the functionalized carbon-silicon composite carrier.
Further, in the step (5), the total mass of the metals in the supported bimetallic carbon-silicon composite catalyst accounts for 0.5-5 wt% (preferably 3%).
Further, in the step (5), the ratio of metal elements in the supported bimetallic carbon-silicon composite catalyst is Au: pd = 1: 1-3 (preferably Au: Pd = 1: 2).
The loaded bimetallic carbon-silicon composite catalyst is applied to the solvent-free selective oxidation of the benzyl alcohol to prepare the benzaldehyde, and the liquid-phase selective oxidation of the benzyl alcohol to prepare the benzaldehyde has the advantages of easy recovery, reusability and high catalytic activity. In heterogeneous catalysts, bimetallic catalysts combining Au with other noble metals (e.g., Pd and Pt) have shown superior catalytic activity for selective oxidation of benzyl alcohol compared to single metal catalysts, especially Au — Pd NPs supported on different supports.
The invention has the beneficial effects that: (1) based on the concept of green chemistry, the biomass resource rice hulls are used as the raw materials of the catalyst carrier, the raw materials are easy to obtain and cheap, the preparation process does not involve high temperature and high pressure, the reaction condition is mild, the requirement on equipment is low, and the energy consumption is greatly reduced; the preparation process of the catalyst is green and environment-friendly, has low cost and can be repeatedly utilized; (2) the prepared supported bimetallic carbon-silicon composite catalyst is applied to the selective oxidation catalytic reaction of benzyl alcohol without solvent, does not relate to other organic solvents, and is green and pollution-free; the catalyst is easy to recover, can be repeatedly used and has high catalytic activity.
Drawings
FIG. 1 shows the example 1, in which N-SiO is supported on a bimetallic carbon-silicon composite catalyst 2 C-600 (a) and SiO 2 An IR spectrum of/C-600 (b);
FIG. 2 shows SiO in the supported bimetallic carbon-silicon composite catalyst in example 1 2 TG-DTG spectrum of/C-600;
FIG. 3 shows the example 1 in which N-SiO is supported on a bimetallic carbon-silicon composite catalyst 2 TG-DTG spectrum of/C-600.
Detailed Description
The invention is further illustrated by the following examples and figures. It should be apparent that the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The chemicals used in the examples of the present invention, such as toluene and methanol, were analytical grade and were obtained from conventional commercial sources unless otherwise specified.
Example 1
The embodiment comprises the following steps:
(1) crushing rice hulls: washing rice hulls with water, drying, crushing and sieving to obtain rice hull powder with the particle size of 90 nm;
(2) rice hull acid treatment: refluxing rice hull powder and a hydrochloric acid solution with the mass fraction of 10% in a reaction kettle for 2 hours according to the solid-liquid ratio of 1: 10, washing a refluxing product with deionized water, and standing overnight in an oven at 105 ℃ to obtain acid-treated rice hull powder;
(3) rice hull pyrolysis and carbonization: putting the acid-treated rice hull powder into a quartz tube, putting the quartz tube into a tube furnace for pyrolysis carbonization at 500 ℃, heating the quartz tube from 20 ℃ to 500 ℃ at the speed of 5 ℃/min, and keeping the temperature for 2 hours until the carbon-silicon composite carrier is obtained;
(4) functionalization: dissolving the carbon-silicon composite carrier in toluene according to the solid-to-liquid ratio of 1: 9 in a narrow-mouth bottle, adding 3-aminopropyltriethoxysilane which is 3 times of the mass of the carbon-silicon composite carrier, refluxing for 48h at 110 ℃, performing centrifugal separation, washing with methanol for several times, and performing vacuum drying to obtain a functionalized carbon-silicon composite carrier;
(5) carrying out metal loading: firstly loading gold on a functionalized carbon-silicon composite carrier, then loading palladium, dispersing 100 mg of carrier in 20 mL of water, adding 0.079mL of 97 mM chloroauric acid aqueous solution, adjusting the pH =7 of the solution, stirring at room temperature for 12 h, dropwise adding sodium borohydride for reduction (the mass concentration is 1mM, NaBH 4: Au =10: 1) under vigorous stirring, after 2h, centrifugally washing the solid, dispersing the solid in 20 mL of water again, adding 1.4 mL of 10 mM palladium chloride aqueous solution, adjusting the pH =7 of the solution, stirring at room temperature for 5 h, dropwise adding sodium borohydride for reduction (the mass concentration is 1mM, NaBH 4: Pd =10: 1) under vigorous stirring, after 2h, centrifugally washing the solid, and drying in a vacuum drying oven at 60 ℃ to obtain the supported bimetallic carbon-silicon composite catalyst.
As can be seen from FIG. 1, 2882-2885 cm-1 belongs to C-H symmetric telescopic vibration; 694 cm-1 to N-H bending vibration; 3416 and 3554 cm-1 belong to the stretching vibration of Si-O-H; 1089-1091 cm-1, 795-800 cm-1 and 463-461 cm-1 are attributed to the asymmetric stretching vibration, symmetric stretching vibration and bending vibration of Si-O-Si, respectively. From the infrared spectrogram, APTES is successfully connected with SiO 2 The surface of/C. With reference to FIG. 2 and FIG. 3, TG-DTG (see FIG. 2) of SiO2/C-5 shows a significant weight loss at 44-105 deg.C, which is caused by the desorption of adsorbed water. TG-DTG of N-SiO2/C-5 (see FIG. 3) exhibited two significant weight losses at 35-164 ℃ and 164-430 ℃. The first obvious weight loss occurs at about 100 ℃, which is caused by the desorption of absorbed water; the second obvious weight loss appears at about 270 ℃, and is SiO 2 Caused by decomposition of aminopropyltriethoxysilane attached to the C-5 surface (mass loss of about 3.8%), and SiO 2 The mass loss increased by about 2.9% compared to C-5.
The supported bimetallic carbon-silicon composite catalyst prepared in the embodiment is named as Au1.5Pd1.5-N-SiO 2 /C-5。
Example 2
The embodiment comprises the following steps:
(1) crushing rice hulls: washing rice hulls with water, drying, crushing and sieving to obtain rice hull powder with the particle size of 80 nm;
(2) treating rice husk acid: refluxing rice hull powder and a hydrochloric acid solution with the mass fraction of 10% in a reaction kettle for 2 hours according to the solid-liquid ratio of 1: 10, washing the refluxed product with deionized water, and drying in an oven at a supplementing temperature of 105 ℃ to obtain acid-treated rice hull powder;
(3) rice hull pyrolysis and carbonization: putting the acid-treated rice hull powder into a quartz tube, putting the quartz tube into a tube furnace, and performing pyrolysis carbonization at 600 ℃ (heating to 600 ℃ from 20 ℃ at the speed of 5 ℃/min, and keeping for 2h, supplementing time or other process conditions) to obtain a carbon-silicon composite carrier;
(4) functionalization: dissolving the carbon-silicon composite carrier in toluene according to the solid-to-liquid ratio of 1: 9 in a narrow-mouth bottle, adding 3-aminopropyltriethoxysilane which is 3 times of the mass of the carbon-silicon composite carrier, refluxing for 48h at 110 ℃, performing centrifugal separation, washing with methanol for several times according to the supplemented volume fraction, and performing vacuum drying to obtain a functionalized carbon-silicon composite carrier;
(5) carrying out metal loading: firstly loading gold on a functionalized carbon-silicon composite carrier, then loading palladium, dispersing 100 mg of carrier in 20 mL of water, adding 0.079mL of 97 mM chloroauric acid aqueous solution, adjusting the pH =7 of the solution, stirring at room temperature for 12 h, dropwise adding sodium borohydride for reduction (the mass concentration is 1mM, NaBH 4: Au =10: 1) under vigorous stirring, after 2h, centrifugally washing the solid, dispersing the solid in 20 mL of water again, adding 1.4 mL of 10 mM palladium chloride aqueous solution, adjusting the pH =7 of the solution, stirring at room temperature for 5 h, dropwise adding sodium borohydride for reduction (the mass concentration is 1mM, NaBH 4: Pd =10: 1) under vigorous stirring, after 2h, centrifugally washing the solid, and drying in a vacuum drying oven at 60 ℃ to obtain the supported bimetallic carbon-silicon composite catalyst.
The supported bimetallic carbon-silicon composite catalyst prepared in the embodiment is named as Au1.5Pd1.5-N-SiO 2 /C-6。
Example 3
The embodiment comprises the following steps:
(1) crushing rice hulls: washing rice hulls with water, drying, crushing and sieving to obtain rice hull powder with the particle size of 70 nm;
(2) treating rice husk acid: refluxing rice hull powder and a hydrochloric acid solution with the mass fraction of 10% in a reaction kettle for 2 hours according to the solid-liquid ratio of 1: 10, washing the reflux product with water, and drying to obtain acid-treated rice hulls;
(3) rice hull pyrolysis and carbonization: and (3) putting the acid-treated rice hulls into a quartz tube, putting the quartz tube into a tube furnace for pyrolysis carbonization at 700 ℃, heating the quartz tube from 20 ℃ to 700 ℃ at the speed of 5 ℃/min, and keeping the temperature for 2 hours. Obtaining the carbon-silicon composite carrier;
(4) functionalization: dissolving the carbon-silicon composite carrier in toluene according to the solid-to-liquid ratio of 1: 9 in a narrow-mouth bottle, adding functionalized carrier 3-aminopropyltriethoxysilane which is 1.5 times of the mass of the carbon-silicon composite carrier, refluxing for 48h at 110 ℃, performing centrifugal separation, washing with methanol for several times, and performing vacuum drying to obtain the functionalized carbon-silicon composite carrier;
(5) carrying out metal loading: firstly loading gold on a functionalized carbon-silicon composite carrier, then loading palladium on the functionalized carbon-silicon composite carrier, dispersing 100 mg of carrier in 20 mL of water, adding 0.079mL of 97 mM chloroauric acid aqueous solution, adjusting the pH of the solution to be =7, stirring at room temperature for 12 h, and dropwise adding sodium borohydride to reduce (the mass concentration is 1mM, NaBH and the like) under vigorous stirring 4 Au =10: 1), 2h later, the solid was washed by centrifugation and dispersed in 20 mL water again, added to 1.4 mL of 10 mM palladium chloride in water, adjusted to pH =7, stirred at room temperature for 5 h, reduced by dropwise addition of sodium borohydride (mass concentration 1mM, NaBH) with vigorous stirring 4 Pd =10: 1), 2 hours later, centrifugally washing the solid, and drying in a vacuum drying oven at 60 ℃ to obtain the supported bimetallic carbon-silicon composite catalyst.
The supported bimetallic carbon-silicon composite catalyst prepared in the embodiment is named as Au1.5Pd1.5-N-SiO 2 /C-7。
Example 4
The embodiment comprises the following steps:
(1) crushing rice hulls: washing rice hulls with water, drying, crushing and sieving to obtain rice hull powder with the particle size of 80 nm;
(2) treating rice husk acid: refluxing rice hull powder and a hydrochloric acid solution with the mass fraction of 10% in a reaction kettle for 2 hours according to the solid-liquid ratio of 1: 10, washing a refluxing product with deionized water, and drying in an oven at 105 ℃ to obtain acid-treated rice hull powder;
(3) rice hull pyrolysis and carbonization: placing the acid-treated rice hull powder into a quartz tube, placing the quartz tube into a tube furnace for pyrolysis carbonization at 800 ℃, heating the quartz tube from 20 ℃ to 800 ℃ at the speed of 5 ℃/min, and keeping the temperature for 2 hours until the carbon-silicon composite carrier is obtained;
(4) functionalization: dissolving the carbon-silicon composite carrier in toluene according to the solid-to-liquid ratio of 1: 9 in a narrow-mouth bottle, adding 3-aminopropyltriethoxysilane which is 3 times of the mass of the carbon-silicon composite carrier, refluxing for 48h at 110 ℃, performing centrifugal separation, washing with methanol for several times, and performing vacuum drying to obtain a functionalized carbon-silicon composite carrier;
(5) carrying out metal loading: firstly loading gold on a functionalized carbon-silicon composite carrier, then loading palladium on the functionalized carbon-silicon composite carrier, dispersing 100 mg of carrier in 20 mL of water, adding 0.079mL of 97 mM chloroauric acid aqueous solution, adjusting the pH of the solution to be =7, stirring at room temperature for 12 h, and dropwise adding sodium borohydride to reduce (the mass concentration is 1mM, NaBH and the like) under vigorous stirring 4 Au =10: 1), 2h later, centrifuged, the solid was washed and re-dispersed in 20 mL of deionized water, added to 1.4 mL of 10 mM palladium chloride in water, the solution pH =7 adjusted, stirred at room temperature for 5 h, reduced by dropwise addition of sodium borohydride (mass concentration 1mM, NaBH) with vigorous stirring 4 Pd =10: 1), 2 hours later, centrifugally washing the solid, and drying in a vacuum drying oven at 60 ℃ to obtain the supported bimetallic carbon-silicon composite catalyst.
The supported bimetallic carbon-silicon composite catalyst prepared in the embodiment is named as Au1.5Pd1.5-N-SiO 2 /C-8。
Example 5
The embodiment comprises the following steps:
(1) crushing rice hulls: washing rice hulls with water, drying, crushing and sieving to obtain rice hull powder with the particle size of 80 nm;
(2) treating rice husk acid: refluxing rice hull powder and a hydrochloric acid solution with the mass fraction of 10% in a reaction kettle for 2 hours according to the solid-to-liquid ratio of 1: 10, washing the refluxed product with deionized water, and drying in an oven at the supplementing temperature to obtain acid-treated rice hull powder;
(3) rice hull pyrolysis and carbonization: putting the acid-treated rice hull powder into a quartz tube, putting the quartz tube into a tube furnace, and performing pyrolysis carbonization at 900 ℃ (heating to 900 ℃ from 20 ℃ at the speed of 5 ℃/min, and keeping for 2h, supplementing time or other process conditions) to obtain a carbon-silicon composite carrier;
(4) functionalization: dissolving the carbon-silicon composite carrier in toluene according to the solid-to-liquid ratio of 1: 9 in a narrow-mouth bottle, adding 3-aminopropyltriethoxysilane which is 3 times of the mass of the carbon-silicon composite carrier, refluxing for 48h at 110 ℃, performing centrifugal separation, washing with methanol for several times according to the supplemented volume fraction, and performing vacuum drying to obtain a functionalized carbon-silicon composite carrier;
(5) carrying out metal loading: firstly loading gold on a functionalized carbon-silicon composite carrier, then loading palladium, dispersing 100 mg of carrier in 20 mL of water, adding 0.079mL of 97 mM chloroauric acid aqueous solution, adjusting the pH =7 of the solution, stirring at room temperature for 12 h, dropwise adding sodium borohydride to reduce (the mass concentration is 1mM, NaBH 4: Au =10: 1) under vigorous stirring, after 2h, centrifugally washing the solid, dispersing the solid in 20 mL of water again, adding 1.4 mL of 10 mM palladium chloride aqueous solution, adjusting the pH =7 of the solution, stirring at room temperature for 5 h, dropwise adding sodium borohydride to reduce (the mass concentration is 1mM, NaBH 4: Pd =10: 1) under vigorous stirring, after 2h, centrifugally washing the solid, and drying in a vacuum drying oven at 60 ℃ to obtain the supported bimetallic carbon-silicon composite catalyst.
The supported bimetallic carbon-silicon composite catalyst prepared in the embodiment is named as Au1.5Pd1.5-N-SiO 2 /C-9。
The catalysts prepared in examples 1-5 were tested for performance: 50 mg of the catalyst prepared in the above examples 1-5 and 15 mmol of benzyl alcohol were put in a 50 ml two-necked flask, covered with an oxygen balloon, and reacted at 110 ℃ under reflux for 5 hours.
The benzyl alcohol and its oxidation product are measured by SHIMADZU GC-14A chromatograph, and the conversion rate and selectivity of the reaction product are calculated by area normalization method. And (3) chromatographic detection conditions: 19091G-B213 capillary column, hydrogen flame ionization detector, column temperature of 80 deg.C, vaporizer temperature of 280 deg.C, and detector temperature of 280 deg.C.
TABLE 1 results of performance tests on catalysts prepared in examples 1-5
As is clear from Table 1, in example 3, the catalyst obtained exhibited the best catalytic performance at a carbonization temperature of 700 ℃.
Claims (7)
1. The supported bimetallic carbon-silicon composite catalyst is characterized by being prepared by the following method:
(1) crushing rice hulls: washing rice husk with water to remove impurities, drying, crushing, and sieving to obtain rice husk powder;
(2) treating rice husk acid: adding a hydrochloric acid solution into the rice hull powder, placing the rice hull powder in a reactor, refluxing, washing the obtained product with water, and drying to obtain acid-treated rice hull powder; placing the rice hull powder and a hydrochloric acid solution with the mass fraction of 10% in a reaction kettle according to the solid-liquid ratio of 1: 10 for refluxing for 2 hours;
(3) rice hull pyrolysis and carbonization: placing the acid-treated rice hull powder into a quartz tube, placing the quartz tube into a tube furnace for pyrolysis carbonization at 700 ℃, heating the quartz tube from 20 ℃ to 700 ℃ at the speed of 5 ℃/min, and keeping the temperature for 2 hours to obtain a carbon-silicon composite carrier;
(4) functionalization: dissolving the carbon-silicon composite carrier in toluene according to the solid-to-liquid ratio of 1: 9, adding 3-aminopropyltriethoxysilane which is 1.5 times of the mass of the carbon-silicon composite carrier to perform surface functionalization, and refluxing for 48 hours at 110 ℃ to obtain the functionalized carbon-silicon composite carrier;
(5) carrying out metal loading: dispersing the functionalized carbon-silicon composite carrier in an aqueous solution containing chloroauric acid and palladium chloride, adjusting the pH value of the solution to be neutral, heating and stirring the obtained mixture, and reducing the mixture by using sodium borohydride to obtain the loaded bimetallic carbon-silicon composite catalyst.
2. The supported bimetallic carbon-silicon composite catalyst as in claim 1, wherein in the step (1) of the preparation method, the grain size of the rice hull powder is less than or equal to 90 nm; the drying was carried out overnight in an oven at 90 ℃.
3. The supported bimetallic carbon-silicon composite catalyst as claimed in claim 1 or 2, wherein in the step (5), the total metal mass in the supported bimetallic carbon-silicon composite catalyst is 0.5-5 wt%.
4. The supported bimetallic carbon-silicon composite catalyst as in claim 3, wherein in the step (5) of the preparation method, the total metal content in the supported bimetallic carbon-silicon composite catalyst is 3%.
5. The supported bimetallic carbon-silicon composite catalyst according to claim 1 or 2, wherein in the step (5) of the preparation method, the ratio of metal elements in the supported bimetallic carbon-silicon composite catalyst is Au: pd = 1: 1-3.
6. The supported bimetallic carbon-silicon composite catalyst as claimed in claim 5, wherein in the step (5) of the preparation method, the ratio of metal elements in the catalyst is Au: pd = 1: 2.
7. The use of the supported bimetallic carbon-silicon composite catalyst as defined in any one of claims 1 to 6 in the solvent-free selective oxidation of benzyl alcohol to prepare benzaldehyde.
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| Solvent-Free Oxidation of Primary Alcohols to Aldehydes Using Au-Pd/TiO2 Catalysts;Dan I. Enache et al.;《SCIENCE》;20060120;第311卷;第362-365页 * |
| Synthesis of Gold Nanoparticles on Rice Husk Silica for Catalysis Applications;Yan Li et al.;《Industrial & Engineering Chemistry Research》;20150426;第54卷;第5656-5663页 * |
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