A C@SiO2-supported Pt-Cu bimetallic alloy catalyst, its preparation method and application

Abstract

The application discloses a C@SiO2 supported Pt-Cu bimetallic alloy catalyst and a preparation method and application thereof. The C@SiO2 supported Pt-Cu bimetallic alloy catalyst is prepared by adopting a co-gel direct synthesis method to load Pt and Cu metal nanoparticles on the surface of a C@SiO2 composite carrier, and the prepared C@SiO2 double-carrier supported Pt-Cu bimetallic alloy catalyst is used in a solvent-free halogenated nitrobenzene hydrogenation reaction, so that the yield of halogenated aromatic aniline is remarkably improved.

Description

Technical Field

[0001] This invention relates to supported Pt-Cu alloy catalysts, their preparation methods, and their application in the solventless selective hydrogenation of halonitrobenzenes to prepare haloanilines. Technical Background

[0002] Chloroaniline is an important fine chemical and industrial synthesis intermediate, obtained by the hydrogenation reduction of chloronitrobenzene (CNB) under certain conditions. It has a wide range of applications, including fragrances, coatings, organic dyes, pesticides, herbicides, and pharmaceutical synthesis. In recent years, with the continuous development of the polyurethane manufacturing industry both domestically and internationally, the demand for chloroaniline (P-CAN) has increased dramatically. Traditional methods for preparing chloroaniline suffer from drawbacks such as poor conversion rates, low yields, complex synthetic routes, and severe environmental pollution. Single noble metals such as Pd and Pt typically exhibit good catalytic performance in the hydrogenation of halides, but their dechlorination is severe, leading to the formation of the byproduct aniline (AN), which reduces the yield of the main product, chloroaniline (CAN). Therefore, improving the hydrogenation selectivity of noble metal catalysts while ensuring high activity is crucial for achieving high-efficiency, large-scale production of p-chloroaniline (P-CAN).

[0003] Firstly, introducing a second metal into supported noble metal catalysts can not only promote synergistic effects between noble metal nanoparticles and second metal particles, further improving the catalyst's catalytic performance, but also partially cover the active sites of the noble metal, preventing further dechlorination to produce byproducts such as aniline (P-CAN) during hydrogenation. This plays a crucial role in improving the catalyst's hydrogenation selectivity. Patent CN115318328A discloses a method for preparing a sandwich-type platinum-cobalt bimetallic catalyst, comprising the following steps: First, ethanol, ammonia, and water are stirred at room temperature, then a silicon source is added and stirred for a certain time to form silicon spheres. Subsequently, Pt and Co metal precursors are added and stirred to adsorb metal ions onto the surface of the silicon spheres. Then, a nitrogen-containing carbon source is introduced at room temperature and stirred for a period of time, followed by filtration, settling, and drying. Finally, the sandwich-type platinum-cobalt bimetallic catalyst is formed by calcination under N2. This catalyst exhibits excellent selectivity and resistance to poisoning during the catalytic reaction, but further improvement is needed in terms of conversion rate. Patent CN109225254B discloses a method for preparing a carbon-supported Pt-Ni bimetallic catalyst. The method first pretreats activated carbon with HNO3, then places the pretreated activated carbon in deionized water, and successively adds chloroplatinic acid and nickel nitrate, stirring until homogeneous. The mixture is then centrifuged and dried to obtain the catalyst precursor. Finally, the carbon-supported Pt-Ni bimetallic catalyst is obtained by H2 reduction at high temperature. This catalyst exhibits excellent reactivity and selectivity, but its noble metal content is relatively large, resulting in high cost (Pt loading is 1-3 wt%).

[0004] Secondly, for metal-based catalysts, the size of the support particles can be adjusted by changing relevant process parameters during catalyst preparation, thereby altering the dispersion of metal nanoparticles on the support surface and improving the high catalytic activity and selectivity of the metal-based catalyst in the hydrogenation reaction. Patent CN113019464A discloses a method for preparing a size-controllable spherical SDB hydrophobic support for a Pt metal catalyst. This method first involves mixing a certain amount of styrene and divinylbenzene monomers, benzoyl peroxide, toluene, and n-heptane. The mixture is then heated to initiate a polymerization reaction. The surface is then roughened using acetone extraction and a physical etching method involving mechanical grinding. Finally, the SDB hydrophobic support is obtained by washing with water. The particle size of the SDB support is controlled by adjusting the ratio of styrene to divinylbenzene monomers. The Pt catalyst supported on the SDB hydrophobic support is then prepared by impregnation. This catalyst exhibits good catalytic activity and selectivity, but its stability needs further improvement. Therefore, by adding a second metal moiety to cover the active sites of noble metals, and by changing the particle size of the support and thus altering the dispersion of metal nanoparticles on the support surface during catalyst preparation, it is beneficial to further improve the hydrogenation selectivity of the catalyst under the premise of high catalytic performance. This is of great significance in the efficient hydrogenation of p-chloronitrobenzene (P-CNB) to p-chloroaniline (P-CAN). Summary of the Invention

[0005] The purpose of this invention is to provide a C@SiO2 supported Pt-Cu bimetallic alloy catalyst, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a C@SiO2-supported Pt-Cu bimetallic alloy catalyst, comprising the following steps:

[0008] (1) Preparation of impregnation solution: Platinum chloride and copper nitrate were dissolved in deionized water to prepare a precious metal impregnation solution with a concentration of PtCl4 of 4.7-27.7 mg / mL and a metal impregnation solution with a concentration of Cu(NO3)2 of 3.9-9 mg / mL.

[0009] (2) Phenolic resin polymerization: A certain amount of phenol, formaldehyde and Na2CO3 (Na2CO3 is beneficial to accelerate the polymerization rate of phenolic resin and increase its curing speed) are added to the reaction vessel, and a gel-like liquid is obtained through polycondensation reaction, which is phenolic resin.

[0010] (3) First calcination: The phenolic resin gel liquid synthesized in step (2) is placed in a quartz boat and then placed in a tube furnace. Under an inert atmosphere (preferably nitrogen or argon) of 30-50 mL / min, the temperature is raised to 600-800℃ at a heating rate of 2-4℃ / min and held for 4-6 hours to obtain microsphere-shaped phenolic resin solid spheres. These spheres are then ground and sieved to serve as a carbon source.

[0011] (4) Synthesis of catalyst precursor: The template agent and 1,3,5-trimethylbenzene (TMB) were dissolved in deionized water, and a certain amount of the noble metal impregnation solution and metal impregnation solution prepared in step (1) were added; then, a certain amount of ammonia solution and tetraethyl orthosilicate (TEOS) were added dropwise to the above mixture, and then the carbon source obtained in step (4) was added to the above mixture; then the mixture was stirred at room temperature for a period of time. During the stirring process of the whole system, tetraethyl orthosilicate and phenolic resin microspheres underwent a co-gel reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microsphere structure. At the same time, Pt and Cu metal nanoparticles were embedded in the silica layer to form a C@SiO2 composite support loaded with Pt-Cu bimetallic catalyst precursor.

[0012] (5) Centrifugation: The catalyst precursor mixture synthesized in step (4) is centrifuged to achieve solid-liquid separation and obtain a paste-like solid product;

[0013] (6) Drying: The paste-like solid product obtained in step (5) is washed with deionized water, and then a certain amount of deionized water is added to the paste-like product obtained after centrifugation to make it evenly dispersed. It is then soaked for a certain time and then spray-dried to obtain the catalyst precursor after spray drying.

[0014] (7) Second calcination: The catalyst precursor obtained in step (6) is heated to 800-1000℃ at a heating rate of 2-4℃ / min under an inert atmosphere (preferably nitrogen or argon) of 30-50mL / min and held for 5-8h to obtain the calcined product.

[0015] (8) Reduction: The product obtained by calcination in step (7) is heated to 200-400℃ at a heating rate of 8-10℃ / min under a hydrogen-argon mixture of 30-50mL / min (preferably with a hydrogen concentration of 5-10%), and held for 2-4h to obtain a C@SiO2 supported Pt-Cu bimetallic alloy catalyst.

[0016] In step (2) of the present invention, preferably, the mass ratio of phenol, formaldehyde and Na2CO3 is 0.09-0.26:0.18-0.50:0.5-1.5.

[0017] In step (2) of the present invention, preferably, the reaction temperature is 60-80℃, the stirring rate is 600-1000r / min, and the polycondensation reaction time is 1-3h.

[0018] In step (3) of the present invention, preferably, the ground solid powder is sieved to 200-300 mesh.

[0019] In step (4) of the present invention, preferably, the template agent is one of CTAB, P123 and F127.

[0020] In step (4) of this invention, preferably, the feeding ratio of the template agent, 1,3,5-trimethylbenzene (TMB), deionized water, ammonia, and TEOS is 0.5-1.5g: 1-3mL: 30-50mL: 1-5mL: 0.25-0.80g, and the feeding of the precious metal impregnation solution and the metal impregnation solution meets the following conditions: the theoretical loading of Pt metal is 0.1-0.7wt%, and the theoretical loading of Cu metal is 0.1-0.3wt%, wherein the theoretical loading = m 金属 / (m 苯酚 +m 甲醛 +m 正硅酸乙酯 )×100%, m 金属 This refers to the mass of precious metals contained in a precious metal immersion solution or the mass of metals contained in a metal immersion solution.

[0021] In step (4) of the present invention, preferably, the stirring rate at room temperature is 600-1000 r / min and the stirring reaction time is 18-24 h.

[0022] In step (5) of the present invention, preferably, the centrifugation rate is 8000-16000 r / min and the centrifugation time is 1-5 min.

[0023] In step (6) of the present invention, preferably, the soaking time is 1-3 hours.

[0024] In step (6) of this invention, preferably, the parameters for spray drying are set as follows: atomization pressure of 0.25-0.8 MPa and air velocity of 3-6 m / s. 3 / h, the peristaltic pump flow rate is 8-16mL / min, and the inlet air temperature is 100-140℃.

[0025] In a second aspect, the present invention provides a C@SiO2-supported Pt-Cu bimetallic alloy catalyst prepared according to the preparation method described in the first aspect.

[0026] Thirdly, the present invention provides the application of the C@SiO2 supported Pt-Cu bimetallic alloy catalyst in the solventless hydrogenation of halonitrobenzene to prepare haloaniline.

[0027] The halonitrobenzenes described in this invention mainly include: p-chloronitrobenzene, m-chloronitrobenzene, p-bromonitrobenzene, m-bromonitrobenzene, p-iodonitrobenzene, and m-iodonitrobenzene.

[0028] The specific application is as follows: a certain amount of halonitrobenzene and the prepared catalyst are added to a high-pressure reactor, and the reaction is stirred under the conditions of 40-160℃ and H2 pressure of 1-2MPa. After the reaction is complete, haloaniline is obtained.

[0029] Preferably, the mass ratio of the catalyst to the reaction substrate is 1:50 to 1:100.

[0030] Preferably, the stirring speed is 1000-1220 rpm.

[0031] Compared with existing technologies, this invention employs a co-gel direct synthesis method to load Pt and Cu metal nanoparticles onto the surface of a C@SiO2 composite support. By changing the type of template agent, C@SiO2-supported bimetallic catalysts with different morphologies (spherical, hierarchical porous, and cubic) are prepared. Under the same metal loading, the particle size of the C@SiO2 composite support is adjusted by changing the amount of template agent, thereby altering the specific surface area and dispersibility of the metal nanoparticles. The prepared catalyst achieves high conversion, high selectivity, and high cycling stability in the solventless hydrogenation of halonitrobenzenes to haloanilines. Specifically, this invention has the following advantages:

[0032] (1) Tetraethyl orthosilicate (TEOS) is an ideal silicon source. Using it as a precursor for SiO2 can efficiently synthesize SiO2 supports. SiO2 supports have high specific surface area and large pore volume. The synergistic effect of combining them with carbon supports is beneficial to significantly improving the dispersion of metal active components and the mass transfer of substrates, thereby ensuring sufficient contact with active centers. This is beneficial to improving the activity and stability of catalysts.

[0033] (2) The direct synthesis method is not only low-cost and simple to operate, but also efficiently promotes the co-gel reaction between tetraethyl orthosilicate (TEOS) and phenolic resin to form a SiO2-encapsulated C spherical composite support. Simultaneously, Pt and Cu bimetallic nanoparticles are loaded onto the surface of the C@SiO2 composite support, forming a bimetallic alloy catalyst. Furthermore, this method is environmentally friendly, produces no toxic substances, has a short catalyst synthesis time, and requires simple post-processing.

[0034] (3) 1,3,5-Trimethylbenzene (TMB), as a pore-expanding agent and structure-directing agent, is beneficial for expanding the pore size of the support, increasing the specific surface area of ​​the support, promoting the adsorption of positively charged Pt and Cu ions, and loading Pt-Cu bimetallic nanoparticles. It also facilitates the adsorption of the reaction substrate by the catalyst, making the reaction efficient and smooth.

[0035] (4) By adjusting the particle size of the support in metal-based catalysts with different morphologies, it is beneficial to improve the catalytic performance, catalytic selectivity and stability of the supported metal catalyst.

[0036] (5) The prepared C@SiO2 dual-supported Pt-Cu bimetallic alloy catalyst was used in the solventless hydrogenation reaction of halonitrobenzene. Due to the high specific surface area and large pore volume of the C@SiO2 composite material, as well as the synergistic effect between Pt and Cu metals, the halonitrobenzene exhibited a high conversion rate. Furthermore, based on the electronic effect between Pt and Cu, further dehalogenation of haloanilines was effectively prevented, enhancing the selectivity of haloanilines. In addition, solventless hydrogenation catalysis facilitated the separation of the product haloaromatic anilines, significantly improving the yield of haloaromatic anilines. Attached Figure Description

[0037] Figure 1 The results are from the catalyst recycling experiment; the cyclic stability of the catalyst was studied.

[0038] Figure 2 These are SEM images of the catalysts, where (a)-(c) are SEM images of the catalysts prepared in Examples 1, 4, and 7; and (d) is the SEM image of the catalyst prepared in Comparative Example 1; demonstrating that different types of catalysts have different surface morphologies.

[0039] Figure 3 This is a TEM image of the catalyst prepared in Example 1. It confirms the structure of the catalyst and the presence of bimetallic alloy particles on the support surface.

[0040] Figure 4 This is the HAADF diffraction pattern of the catalyst prepared in Example 1. It demonstrates the formation of the C@SiO2 composite support and the successful loading of the Pt-Cu bimetallic alloy onto the C@SiO2 surface.

[0041] Figure 5 These are XRD patterns of the catalysts prepared in Examples 1, 4, 7, and Comparative Example 1. This demonstrates that the different catalysts have different degrees of crystallinity. Specific implementation methods

[0042] The embodiments listed in this invention will be described in detail below through specific examples, but the scope of protection of this invention is not limited to the following examples.

[0043] The phenol, formaldehyde, ammonia, and tetraethyl orthosilicate used in the embodiments of the present invention are all commercially available products. The phenol has a mass percentage concentration of 30% and a density of 1.071 g / mL; the formaldehyde has a mass percentage concentration of 30% and a density of 0.815 g / mL; the ammonia has a mass percentage concentration of 28%; and the tetraethyl orthosilicate has a mass percentage concentration of 28% and a density of 0.94 g / mL.

[0044] Example 1

[0045] (1) Weigh 1.09g PtCl4 and 0.39g Cu(NO3)2 into 100mL volumetric flasks, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0046] (2) Add 0.3 mL of phenol (30%), 0.75 mL of formaldehyde (30%), and 0.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser switch to allow the phenol and formaldehyde to undergo a condensation reaction at 60°C and 600 r / min for 1 hour. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0047] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 30 mL / min, heat it to 600℃ at a heating rate of 2℃ / min and keep it for 4 hours to obtain calcined microsphere-shaped phenolic resin solid spheres, which can be used as carbon source.

[0048] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 200-220 mesh.

[0049] (5) Synthesis of catalyst precursor: 0.5 g CTAB and 1 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 30 mL deionized water, and then 0.6 mL of the precious metal impregnation solution prepared in step (1) and 1.2 mL of the metal impregnation solution were added. Then, 1 mL of ammonia solution (28%) and 1 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin beads ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 600 r / min for 18 h at room temperature. During the stirring process of the entire system, tetraethyl orthosilicate and phenolic resin microspheres undergo a co-gelation reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microspheres. At the same time, Pt and Cu metal nanoparticles are embedded in the silica layer, forming a C@SiO2 composite support for supporting Pt-Cu bimetallic catalyst precursors.

[0050] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 8000 r / min for 1 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0051] (7) Drying: Wash the centrifuged product obtained in step (6) with deionized water, then add 15 mL of deionized water to the paste obtained after centrifugation to disperse it evenly, soak it for 1 hour, and then spray dry it. That is, put the paste soaked in deionized water into an atomizer, adjust the air compressor outlet pressure to 0.25 MPa to atomize it. Transfer the atomized product to the drying tower, and then adjust the air input to 3 mL. 3 Spray drying was performed at a flow rate of 8 mL / min using a peristaltic pump and an inlet air temperature of 100 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0052] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 800℃ for 5 hours under N2 atmosphere with a gas flow rate of 30 mL / min and a heating rate of 2℃ / min.

[0053] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 200℃ for 2 hours under an H2 / Ar atmosphere (H2 concentration of 5%) with a gas flow rate of 30 mL / min and a heating rate of 8℃ / min. A C@SiO2-supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.7 wt% and Cu loading of 0.3 wt%) was prepared.

[0054] (10) Add 0.01 g of catalyst and 1 g of m-chloronitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave with H2 five times. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 40 °C, start stirring at 1000 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100%.

[0055] Example 2

[0056] (1) Weigh 1.8g PtCl4 and 0.52g Cu(NO3)2 into 100mL volumetric flasks respectively, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0057] (2) Add 0.3 mL of phenol (30%), 1.1 mL of formaldehyde (30%), and 1 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser switch to allow the phenol and formaldehyde to undergo a polycondensation reaction at 70°C and 800 r / min for 2 hours. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0058] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 40 mL / min, heat it to 700℃ at a heating rate of 3℃ / min and keep it for 5 hours to obtain phenolic resin solid spheres in the shape of microspheres after calcination, which can be used as carbon source.

[0059] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 240-260 mesh.

[0060] (5) Synthesis of catalyst precursor: 1 g CTAB and 2 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 40 mL deionized water, and then 0.6 mL of the precious metal impregnation solution prepared in step (1) and 1 mL of metal impregnation solution were added. Then, 3 mL of ammonia solution (28%) and 2 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin microspheres ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 800 r / min for 20 h at room temperature. During the stirring process, tetraethyl orthosilicate and phenolic resin microspheres underwent a co-gel reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microsphere structure. At the same time, Pt and Cu metal nanoparticles were embedded in the silica layer, forming a C@SiO2 composite support for a Pt-Cu bimetallic catalyst precursor.

[0061] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 10,000 r / min for 3 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0062] (7) Drying: The centrifuged product obtained in step (6) is washed with deionized water. Then, 20 mL of deionized water is added to the paste-like product obtained after centrifugation to disperse it evenly. The paste-like product is soaked for 2 hours and then spray-dried. That is, the paste-like product soaked in deionized water is put into an atomizer, and the air compressor outlet pressure is adjusted to 0.5 MPa for atomization. The atomized product is transferred to the drying tower, and then the air input is adjusted to 4 mL. 3 Spray drying was performed at a flow rate of 10 mL / min using a peristaltic pump and an inlet air temperature of 120 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0063] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 900℃ for 6 hours under N2 atmosphere with a gas flow rate of 40 mL / min and a heating rate of 3℃ / min.

[0064] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 300℃ for 3 hours under an H2 / Ar atmosphere (H2 concentration of 8%) with a gas flow rate of 40 mL / min and a heating rate of 9℃ / min. A C@SiO2 supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.7 wt% and Cu loading of 0.2 wt%) was prepared.

[0065] (10) Add 0.01 g of catalyst and 1 g of p-chloronitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 80 °C, start stirring at 1100 rpm, and analyze the selectivity of the product and record the reaction time when the conversion rate of the reaction substrate is 100% using a chromatograph equipped with GC.

[0066] Example 3

[0067] (1) Weigh 2.77g PtCl4 and 0.81g Cu(NO3)2 into 100mL volumetric flasks respectively, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0068] (2) Add 0.3 mL of phenol (30%), 2 mL of formaldehyde (30%), and 1.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser water switch to allow the phenol and formaldehyde to undergo a condensation reaction at 80°C and 1000 r / min for 3 hours. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0069] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 50 mL / min, heat it to 800℃ at a heating rate of 4℃ / min and keep it for 6 hours to obtain phenolic resin solid spheres in the shape of microspheres after calcination, which can be used as carbon source.

[0070] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 280-300 mesh.

[0071] (5) Synthesis of catalyst precursor: 1.5 g CTAB and 3 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 50 mL deionized water, and then 0.6 mL of the precious metal impregnation solution prepared in step (1) and 0.5 mL of the metal impregnation solution were added. Then, 5 mL of ammonia solution (28%) and 3 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin beads ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 1000 r / min for 24 h at room temperature. During the stirring process of the entire system, tetraethyl orthosilicate and phenolic resin microspheres undergo a co-gelation reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microspheres. At the same time, Pt and Cu metal nanoparticles are embedded in the silica layer, forming a C@SiO2 composite support for supporting Pt-Cu bimetallic catalyst precursors.

[0072] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 16000 r / min for 5 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0073] (7) Drying: The centrifuged product obtained in step (6) is washed with deionized water. Then, 25 mL of deionized water is added to the paste-like product obtained after centrifugation to disperse it evenly. The paste-like product is soaked for 3 hours and then spray-dried. That is, the paste-like product soaked in deionized water is put into an atomizer, and the air compressor outlet pressure is adjusted to 0.8 MPa for atomization. The atomized product is transferred to the drying tower, and then the air input is adjusted to 5 mL. 3 Spray drying was performed at a flow rate of 12 mL / min using a peristaltic pump and an inlet air temperature of 140 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0074] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 1000℃ for 8 hours under N2 atmosphere with a gas flow rate of 50 mL / min and a heating rate of 4℃ / min.

[0075] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 400℃ for 4 hours under an H2 / Ar atmosphere (H2 concentration of 10%) with a gas flow rate of 50 mL / min and a heating rate of 10℃ / min. A C@SiO2 supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.7 wt% and Cu loading of 0.1 wt%) was prepared.

[0076] (10) Add 0.01 g of catalyst and 1 g of p-bromonitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 120 °C, start stirring at 1220 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100% using a chromatograph equipped with GC.

[0077] Example 4

[0078] (1) Weigh 1.11g PtCl4 and 0.47g Cu(NO3)2 into 100mL volumetric flasks, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0079] (2) Add 0.6 mL of phenol (30%), 0.75 mL of formaldehyde (30%), and 0.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser switch to allow the phenol and formaldehyde to undergo a condensation reaction at 60°C and 600 r / min for 1 hour. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0080] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under Ar at a rate of 2℃ / min, heat it to 600℃ and keep it for 4h to obtain calcined microsphere-shaped phenolic resin solid spheres, which can be used as carbon source.

[0081] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 200-220 mesh.

[0082] (5) Synthesis of catalyst precursor: 0.5 g F127 and 1 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 30 mL deionized water, and then 0.5 mL of the precious metal impregnation solution prepared in step (1) and 1.2 mL of the metal impregnation solution were added. Then, 1 mL of ammonia solution (28%) and 1 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin beads ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 600 r / min for 18 h at room temperature. During the stirring process of the entire system, tetraethyl orthosilicate and phenolic resin microspheres undergo a co-gelation reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microspheres. At the same time, Pt and Cu metal nanoparticles are embedded in the silica layer, forming a C@SiO2 composite support for supporting Pt-Cu bimetallic catalyst precursors.

[0083] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 8000 r / min for 1 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0084] (7) Drying: Wash the centrifuged product obtained in step (6) with deionized water, then add 15 mL of deionized water to the paste obtained after centrifugation to disperse it evenly, soak it for 1 hour, and then spray dry it. That is, put the paste soaked in deionized water into an atomizer, adjust the air compressor outlet pressure to 0.25 MPa to atomize it. Transfer the atomized product to the drying tower, and then adjust the air input to 3 mL. 3 Spray drying was performed at a flow rate of 8 mL / min using a peristaltic pump and an inlet air temperature of 100 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0085] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 800℃ for 5 hours under an Ar atmosphere with a gas flow rate of 30 mL / min and a heating rate of 2℃ / min.

[0086] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 200℃ for 2 hours under an H2 / Ar atmosphere (H2 concentration of 5%) with a gas flow rate of 30 mL / min and a heating rate of 8℃ / min. A C@SiO2-supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.5 wt% and Cu loading of 0.3 wt%) was prepared.

[0087] (10) Add 0.01 g of catalyst and 2 g of m-bromonitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 2 MPa with H2 at room temperature. Then heat the autoclave to 50 °C, start stirring at 1000 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100%.

[0088] Example 5

[0089] (1) Weigh 1.71g PtCl4 and 0.58g Cu(NO3)2 into 100mL volumetric flasks, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0090] (2) Add 0.6 mL of phenol (30%), 1.1 mL of formaldehyde (30%), and 1 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser water switch to allow the phenol and formaldehyde to undergo a condensation reaction at 70°C and 800 r / min for 2 hours. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0091] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under Ar at a rate of 3℃ / min, heat it to 700℃ and hold it for 5h to obtain calcined microsphere-shaped phenolic resin solid spheres, which can be used as carbon source.

[0092] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 240-260 mesh.

[0093] (5) Synthesis of catalyst precursor: 1 g F127 and 2 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 40 mL deionized water, and 0.5 mL of the precious metal impregnation solution prepared in step (1) and 1 mL of metal impregnation solution were added. Then, 3 mL of ammonia solution (28%) and 2 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin microspheres ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 800 r / min for 20 h at room temperature. During the stirring process, tetraethyl orthosilicate and phenolic resin microspheres underwent a co-gel reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microsphere structure. At the same time, Pt and Cu metal nanoparticles were embedded in the silica layer, forming a C@SiO2 composite support for a Pt-Cu bimetallic catalyst precursor. Finally, the dried solid product is collected at the bottom of the drying tower to obtain the catalyst precursor after spray drying.

[0094] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 10,000 r / min for 3 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0095] (7) Drying: The centrifuged product obtained in step (6) is washed with deionized water. Then, 20 mL of deionized water is added to the paste-like product obtained after centrifugation to disperse it evenly. The paste-like product is soaked for 2 hours and then spray-dried. That is, the paste-like product soaked in deionized water is put into an atomizer, and the air compressor outlet pressure is adjusted to 0.5 MPa for atomization. The atomized product is transferred to the drying tower, and then the air input is adjusted to 4 mL. 3 Spray drying was performed at a flow rate of 10 mL / min using a peristaltic pump and an inlet air temperature of 120°C.

[0096] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 900℃ for 6 hours under an Ar atmosphere with a gas flow rate of 40 mL / min and a heating rate of 3℃ / min.

[0097] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 300℃ for 3 hours under an H2 / Ar atmosphere (H2 concentration of 8%) with a gas flow rate of 40 mL / min and a heating rate of 9℃ / min. A C@SiO2 supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.5 wt% and Cu loading of 0.2 wt%) was prepared.

[0098] (10) Add 0.01 g of catalyst and 2 g of p-iodonitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 2 MPa with H2 at room temperature. Then heat the autoclave to 160 °C, start stirring at 1100 rpm, and analyze the selectivity of the product and record the reaction time when the conversion rate of the reaction substrate is 100% using a chromatograph equipped with GC.

[0099] Example 6

[0100] (1) Weigh 2.54g PtCl4 and 0.86g Cu(NO3)2 into 100mL volumetric flasks respectively, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0101] (2) Add 0.6 mL of phenol (30%), 2 mL of formaldehyde (30%), and 1.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser water switch to allow the phenol and formaldehyde to undergo a condensation reaction at 80°C and 1000 r / min for 3 hours. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0102] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under Ar at a rate of 4℃ / min, heat it to 800℃ and keep it for 6h to obtain calcined microsphere-shaped phenolic resin solid spheres, which can be used as carbon source.

[0103] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 280-300 mesh.

[0104] (5) Synthesis of catalyst precursor: 1.5 g F127 and 3 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 50 mL deionized water, and then 0.5 mL of the precious metal impregnation solution prepared in step (1) and 0.5 mL of the metal impregnation solution were added. Then, 5 mL of ammonia solution (28%) and 3 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin beads ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 1000 r / min for 24 h at room temperature. During the stirring process of the entire system, tetraethyl orthosilicate and phenolic resin microspheres undergo a co-gelation reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microspheres. At the same time, Pt and Cu metal nanoparticles are embedded in the silica layer, forming a C@SiO2 composite support for supporting Pt-Cu bimetallic catalyst precursors.

[0105] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 16000 r / min for 5 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0106] (7) Drying: The centrifuged product obtained in step (6) is washed with deionized water. Then, 25 mL of deionized water is added to the paste-like product obtained after centrifugation to disperse it evenly. The paste-like product is soaked for 3 hours and then spray-dried. That is, the paste-like product soaked in deionized water is put into an atomizer, and the air compressor outlet pressure is adjusted to 0.8 MPa for atomization. The atomized product is transferred to the drying tower, and then the air input is adjusted to 5 mL. 3 Spray drying was performed at a flow rate of 12 mL / min using a peristaltic pump and an inlet air temperature of 140 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0107] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 1000℃ for 8 hours under an Ar atmosphere with a gas flow rate of 50 mL / min and a heating rate of 4℃ / min.

[0108] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 400℃ for 4 hours under an H2 / Ar atmosphere (H2 concentration of 10%) with a gas flow rate of 50 mL / min and a heating rate of 10℃ / min. A C@SiO2 supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.5 wt% and Cu loading of 0.1 wt%) was prepared.

[0109] (10) Add 0.01 g of catalyst and 1 g of m-iodonitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 2 MPa with H2 at room temperature. Then heat the autoclave to 60 °C, start stirring at 1220 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100% using a chromatograph equipped with GC.

[0110] Example 7

[0111] (1) Weigh 0.6g PtCl4 and 0.51g Cu(NO3)2 into 100mL volumetric flasks respectively, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0112] (2) Add 0.8 mL of phenol (30%), 0.75 mL of formaldehyde (30%), and 0.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser water switch to allow the phenol and formaldehyde to undergo a condensation reaction at 60°C and 600 r / min for 1 hour. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0113] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 30 mL / min, heat it to 600℃ at a heating rate of 2℃ / min and keep it for 4 hours to obtain calcined microsphere-shaped phenolic resin solid spheres, which can be used as carbon source.

[0114] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 200-220 mesh.

[0115] (5) Synthesis of catalyst precursor: 0.5 g P123 and 1 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 30 mL deionized water, and then 0.4 mL of the precious metal impregnation solution prepared in step (1) and 1.2 mL of the metal impregnation solution were added. Then, 1 mL of ammonia solution (28%) and 1 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin beads ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at a stirring rate of 600 r / min for 18 h at room temperature. During the stirring process of the entire system, tetraethyl orthosilicate and phenolic resin microspheres undergo a co-gelation reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microspheres. At the same time, Pt and Cu metal nanoparticles are embedded in the silica layer, forming a C@SiO2 composite support for supporting Pt-Cu bimetallic catalyst precursors.

[0116] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 8000 r / min for 1 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0117] (7) Drying: Wash the centrifuged product obtained in step (6) with deionized water, then add 15 mL of deionized water to the paste obtained after centrifugation to disperse it evenly, soak it for 1 hour, and then spray dry it. That is, put the paste soaked in deionized water into an atomizer, adjust the air compressor outlet pressure to 0.25 MPa to atomize it. Transfer the atomized product to the drying tower, and then adjust the air input to 3 mL. 3 Spray drying was performed at a flow rate of 8 mL / min using a peristaltic pump and an inlet air temperature of 100 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0118] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 800℃ for 5 hours under N2 atmosphere with a gas flow rate of 30 mL / min and a heating rate of 2℃ / min.

[0119] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 200℃ for 2 hours under an H2 / Ar atmosphere (H2 concentration of 5%) with a gas flow rate of 30 mL / min and a heating rate of 8℃ / min. A C@SiO2-supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.2 wt% and Cu loading of 0.3 wt%) was prepared.

[0120] (10) Add 0.01 g of catalyst and 1 g of p-chloronitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 80 °C, start stirring at 1000 rpm, and analyze the selectivity of the product and record the reaction time when the conversion rate of the reaction substrate is 100%.

[0121] Example 8

[0122] (1) Weigh 0.91g PtCl4 and 0.62g Cu(NO3)2 into 100mL volumetric flasks respectively, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0123] (2) Add 0.8 mL of phenol (30%), 1.1 mL of formaldehyde (30%), and 1 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser water switch to allow the phenol and formaldehyde to undergo a condensation reaction at 70°C and 800 r / min for 2 hours. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0124] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 40 mL / min, heat it to 700℃ at a heating rate of 3℃ / min and keep it for 5 hours to obtain phenolic resin solid spheres in the shape of microspheres after calcination, which can be used as carbon source.

[0125] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 240-260 mesh.

[0126] (5) Synthesis of catalyst precursor: 1 g P123 and 2 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 40 mL deionized water, and 0.4 mL of the precious metal impregnation solution prepared in step (1) and 1 mL of metal impregnation solution were added. Then, 3 mL of ammonia solution (28%) and 2 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin microspheres ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 800 r / min for 20 h at room temperature. During the stirring process, tetraethyl orthosilicate and phenolic resin microspheres underwent a co-gel reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microsphere structure. At the same time, Pt and Cu metal nanoparticles were embedded in the silica layer, forming a C@SiO2 composite support for a Pt-Cu bimetallic catalyst precursor.

[0127] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 10,000 r / min for 3 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0128] (7) Drying: The centrifuged product obtained in step (6) is washed with deionized water. Then, 20 mL of deionized water is added to the paste-like product obtained after centrifugation to disperse it evenly. The paste-like product is soaked for 2 hours and then spray-dried. That is, the paste-like product soaked in deionized water is put into an atomizer, and the air compressor outlet pressure is adjusted to 0.5 MPa for atomization. The atomized product is transferred to the drying tower, and then the air input is adjusted to 4 mL. 3 Spray drying was performed at a flow rate of 10 mL / min using a peristaltic pump and an inlet air temperature of 120 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0129] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 900℃ for 6 hours under N2 atmosphere with a gas flow rate of 40 mL / min and a heating rate of 3℃ / min.

[0130] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 300℃ for 3 hours under an H2 / Ar atmosphere (H2 concentration of 8%) with a gas flow rate of 40 mL / min and a heating rate of 9℃ / min. A C@SiO2 supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.2 wt% and Cu loading of 0.2 wt%) was prepared.

[0131] (10) Add 0.01 g of catalyst and 1 g of m-nitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 40 °C, start stirring at 1100 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100%.

[0132] Example 9

[0133] (1) Weigh 1.33g PtCl4 and 0.9g Cu(NO3)2 into 100mL volumetric flasks respectively, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0134] (2) Add 0.8 mL of phenol (30%), 2 mL of formaldehyde (30%), and 1.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser switch to allow the phenol and formaldehyde to undergo a condensation reaction at 80°C and 1000 r / min for 3 hours. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0135] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 50 mL / min, heat it to 800℃ at a heating rate of 4℃ / min and keep it for 6 hours to obtain phenolic resin solid spheres in the shape of microspheres after calcination, which can be used as carbon source.

[0136] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 280-300 mesh.

[0137] (5) Synthesis of catalyst precursor: 1.5 g P123 and 3 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 50 mL deionized water, and then 0.4 mL of the precious metal impregnation solution prepared in step (1) and 0.5 mL of the metal impregnation solution were added. Then, 5 mL of ammonia solution (28%) and 3 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin beads ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 1000 r / min for 24 h at room temperature. During the stirring process of the entire system, tetraethyl orthosilicate and phenolic resin microspheres undergo a co-gelation reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microspheres. At the same time, Pt and Cu metal nanoparticles are embedded in the silica layer, forming a C@SiO2 composite support for supporting Pt-Cu bimetallic catalyst precursors.

[0138] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 16000 r / min for 5 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0139] (7) Drying: The centrifuged product obtained in step (6) is washed with deionized water. Then, 25 mL of deionized water is added to the paste-like product obtained after centrifugation to disperse it evenly. The paste-like product is soaked for 3 hours and then spray-dried. That is, the paste-like product soaked in deionized water is put into an atomizer, and the air compressor outlet pressure is adjusted to 0.8 MPa for atomization. The atomized product is transferred to the drying tower, and then the air input is adjusted to 5 mL. 3 Spray drying was performed at a flow rate of 12 mL / min using a peristaltic pump and an inlet air temperature of 140 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0140] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 1000℃ for 8 hours under N2 atmosphere with a gas flow rate of 50 mL / min and a heating rate of 4℃ / min.

[0141] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 400℃ for 4 hours under an H2 / Ar atmosphere (H2 concentration of 10%) with a gas flow rate of 50 mL / min and a heating rate of 10℃ / min. A C@SiO2 supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.2 wt% and Cu loading of 0.1 wt%) was prepared.

[0142] (10) Add 0.01 g of catalyst and 1 g of p-bromonitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 120 °C, start stirring at 1220 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100% using a chromatograph equipped with GC.

[0143] Example 10

[0144] (1) Weigh 0.47g PtCl4 and 0.4g Cu(NO3)2 into 100mL volumetric flasks respectively, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0145] (2) Add 0.3 mL of phenol (30%), 0.75 mL of formaldehyde (30%), and 0.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser switch to allow the phenol and formaldehyde to undergo a condensation reaction at 60°C and 600 r / min for 1 hour. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0146] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 30 mL / min, heat it to 600℃ at a heating rate of 2℃ / min and keep it for 4 hours to obtain calcined microsphere-shaped phenolic resin solid spheres, which can be used as carbon source.

[0147] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 200-220 mesh.

[0148] (5) Synthesis of catalyst precursor: 0.5 g CTAB and 1 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 30 mL deionized water, and then 0.2 mL of the precious metal impregnation solution prepared in step (1) and 1.2 mL of the metal impregnation solution were added. Then, 1 mL of ammonia solution (28%) and 1 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin beads ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at a stirring rate of 600 r / min for 18 h at room temperature. During the stirring process of the entire system, tetraethyl orthosilicate and phenolic resin microspheres undergo a co-gelation reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microspheres. At the same time, Pt and Cu metal nanoparticles are embedded in the silica layer, forming a C@SiO2 composite support for supporting Pt-Cu bimetallic catalyst precursors.

[0149] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 8000 r / min for 1 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0150] (7) Drying: Wash the centrifuged product obtained in step (6) with deionized water, then add 15 mL of deionized water to the paste obtained after centrifugation to disperse it evenly, soak it for 1 hour, and then spray dry it. That is, put the paste soaked in deionized water into an atomizer, adjust the air compressor outlet pressure to 0.25 MPa to atomize it. Transfer the atomized product to the drying tower, and then adjust the air input to 3 mL. 3 Spray drying was performed at a flow rate of 8 mL / min using a peristaltic pump and an inlet air temperature of 100 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0151] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 800℃ for 5 hours under N2 atmosphere with a gas flow rate of 30 mL / min and a heating rate of 2℃ / min.

[0152] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 200°C for 2 hours under an H2 / Ar atmosphere (H2 concentration of 5%) with a gas flow rate of 30 mL / min and a heating rate of 8 °C / min. A C@SiO2-supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.1 wt% and Cu loading of 0.3 wt%) was prepared.

[0153] (10) Add 0.01 g of catalyst and 2 g of m-bromonitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 40 °C, start stirring at 1000 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100%.

[0154] Example 11

[0155] (1) Weigh 0.77g PtCl4 and 0.52g Cu(NO3)2 into 100mL volumetric flasks, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0156] (2) Add 0.3 mL of phenol (30%), 1.1 mL of formaldehyde (30%), and 1 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser water switch to allow the phenol and formaldehyde to undergo a condensation reaction at 70°C and 800 r / min for 2 hours. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0157] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 40 mL / min, heat it to 700℃ at a heating rate of 3℃ / min and keep it for 5 hours to obtain phenolic resin solid spheres in the shape of microspheres after calcination, which can be used as carbon source.

[0158] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 240-260 mesh.

[0159] (5) Synthesis of catalyst precursor: 1 g CTAB and 2 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 40 mL deionized water, and 0.2 mL of the precious metal impregnation solution prepared in step (1) and 1 mL of metal impregnation solution were added. Then, 3 mL of ammonia solution (28%) and 2 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin microspheres ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 800 r / min for 20 h at room temperature. During the stirring process, tetraethyl orthosilicate and phenolic resin microspheres underwent a co-gel reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microsphere structure. At the same time, Pt and Cu metal nanoparticles were embedded in the silica layer, forming a C@SiO2 composite support for a Pt-Cu bimetallic catalyst precursor.

[0160] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 10,000 r / min for 3 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0161] (7) Drying: The centrifuged product obtained in step (6) is washed with deionized water. Then, 20 mL of deionized water is added to the paste-like product obtained after centrifugation to disperse it evenly. The paste-like product is soaked for 2 hours and then spray-dried. That is, the paste-like product soaked in deionized water is put into an atomizer, and the air compressor outlet pressure is adjusted to 0.5 MPa for atomization. The atomized product is transferred to the drying tower, and then the air input is adjusted to 4 mL. 3 Spray drying was performed at a flow rate of 10 mL / min using a peristaltic pump and an inlet air temperature of 120 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0162] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 900℃ for 6 hours under N2 atmosphere with a gas flow rate of 40 mL / min and a heating rate of 3℃ / min.

[0163] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 300℃ for 3 hours under an H2 / Ar atmosphere (H2 concentration of 8%) with a gas flow rate of 40 mL / min and a heating rate of 9℃ / min. A C@SiO2 supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.1 wt% and Cu loading of 0.2 wt%) was prepared.

[0164] (10) Add 0.01 g of catalyst and 2 g of p-iodonitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave with H2 five times. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 160 °C, start stirring at 1100 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100%.

[0165] Example 12

[0166] (1) Weigh 1.18g PtCl4 and 0.8g Cu(NO3)2 into 100mL volumetric flasks respectively, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0167] (2) Add 0.3 mL of phenol (30%), 2 mL of formaldehyde (30%), and 1.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser water switch to allow the phenol and formaldehyde to undergo a condensation reaction at 80°C and 1000 r / min for 3 hours. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0168] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 50 mL / min, heat it to 800℃ at a heating rate of 4℃ / min and keep it for 6 hours to obtain phenolic resin solid spheres in the shape of microspheres after calcination, which can be used as carbon source.

[0169] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 280-300 mesh.

[0170] (5) Synthesis of catalyst precursor: 1.5 g CTAB and 3 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 50 mL deionized water, and then 0.2 mL of the precious metal impregnation solution prepared in step (1) and 0.5 mL of the metal impregnation solution were added. Then, 5 mL of ammonia water (28%) solution and 3 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin beads ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 1000 r / min for 24 h at room temperature. During the stirring process of the entire system, tetraethyl orthosilicate and phenolic resin microspheres undergo a co-gelation reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microspheres. At the same time, Pt and Cu metal nanoparticles are embedded in the silica layer, forming a C@SiO2 composite support for supporting Pt-Cu bimetallic catalyst precursors.

[0171] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 16000 r / min for 5 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0172] (7) Drying: The centrifuged product obtained in step (6) is washed with deionized water. Then, 25 mL of deionized water is added to the paste-like product obtained after centrifugation to disperse it evenly. The paste-like product is soaked for 3 hours and then spray-dried. That is, the paste-like product soaked in deionized water is put into an atomizer, and the air compressor outlet pressure is adjusted to 0.8 MPa for atomization. The atomized product is transferred to the drying tower, and then the air input is adjusted to 5 mL. 3 Spray drying was performed at a flow rate of 12 mL / min using a peristaltic pump and an inlet air temperature of 140 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0173] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 1000℃ for 8 hours under N2 atmosphere with a gas flow rate of 50 mL / min and a heating rate of 4℃ / min.

[0174] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 400℃ for 4 hours under an H2 / Ar atmosphere (H2 concentration of 10%) with a gas flow rate of 50 mL / min and a heating rate of 10℃ / min. A C@SiO2 supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.1 wt% and Cu loading of 0.1 wt%) was prepared.

[0175] (10) Add 0.01 g of catalyst and 2 g of m-iodonitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave with H2 five times. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 60 °C, start stirring at 1220 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100% using a chromatograph equipped with GC.

[0176] Comparative Example 1

[0177] The catalyst preparation process of this comparative example is similar to that of Example 1, except that 1,3,5-trimethylbenzene (TMB) was not added in step (5). Compared with Example 1, the catalyst prepared in this comparative example has smaller pore volume and pore size, and relatively weaker adsorption-mass transfer.

[0178] Furthermore, the preparation process of this comparative catalyst is as follows:

[0179] (1) Weigh 1.09g PtCl4 and 0.39g Cu(NO3)2 into 100mL volumetric flasks, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0180] (2) Add 0.3 mL of phenol (30%), 0.75 mL of formaldehyde (30%), and 0.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser switch to allow the phenol and formaldehyde to undergo a condensation reaction at 60°C and 600 r / min for 1 hour. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0181] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 30 mL / min, heat it to 600℃ at a heating rate of 2℃ / min and keep it for 4 hours to obtain calcined microsphere-shaped phenolic resin solid spheres, which can be used as carbon source.

[0182] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 200-220 mesh.

[0183] (5) Synthesis of catalyst precursor: 0.5 g CTAB was dissolved in a beaker containing 30 mL deionized water, and then 0.6 mL of the noble metal impregnation solution prepared in step (1) and 1.2 mL of metal impregnation solution were added. Then, 1 mL of ammonia solution (28%) and 1 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin microspheres ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 600 r / min for 18 h at room temperature. During the stirring process, tetraethyl orthosilicate and phenolic resin microspheres underwent a co-gel reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microsphere structure. At the same time, Pt and Cu metal nanoparticles were embedded in the silica layer, forming a C@SiO2 composite support for a Pt-Cu bimetallic catalyst precursor.

[0184] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 8000 r / min for 1 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0185] (7) Drying: Wash the centrifuged product obtained in step (6) with deionized water, then add 15 mL of deionized water to the paste obtained after centrifugation to disperse it evenly, soak it for 1 hour, and then spray dry it. That is, put the paste soaked in deionized water into an atomizer, adjust the air compressor outlet pressure to 0.25 MPa to atomize it. Transfer the atomized product to the drying tower, and then adjust the air input to 3 mL. 3 Spray drying was performed at a flow rate of 8 mL / min using a peristaltic pump and an inlet air temperature of 100 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0186] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 800℃ for 5 hours under N2 atmosphere with a gas flow rate of 30 mL / min and a heating rate of 2℃ / min.

[0187] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 200℃ for 2 hours under an H2 / Ar atmosphere (H2 concentration of 5%) with a gas flow rate of 30 mL / min and a heating rate of 8℃ / min. A C@SiO2-supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.7 wt% and Cu loading of 0.3 wt%) was prepared.

[0188] (10) Add 0.01 g of catalyst and 1 g of m-chloronitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 2 MPa with H2 at room temperature. Then heat the autoclave to 40 °C, start stirring at 1220 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100% using a chromatograph equipped with GC.

[0189] Comparative Example 2

[0190] The catalyst preparation process of this comparative example is similar to that of Example 1, except that no Pt noble metal impregnation solution was prepared in step (1) and no noble metal Pt was loaded in step (5).

[0191] Furthermore, the preparation process of this comparative catalyst is as follows:

[0192] (1) Weigh 0.39 g Cu(NO3)2 into a 100 mL volumetric flask, dilute with deionized water to the mark, and prepare a metal impregnation solution.

[0193] (2) Add 0.3 mL of phenol (30%), 0.75 mL of formaldehyde (30%), and 0.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser switch to allow the phenol and formaldehyde to undergo a condensation reaction at 60°C and 600 r / min for 1 hour. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0194] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 30 mL / min, heat it to 600℃ at a heating rate of 2℃ / min and keep it for 4 hours to obtain calcined microsphere-shaped phenolic resin solid spheres, which can be used as carbon source.

[0195] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 200-220 mesh.

[0196] (5) Synthesis of catalyst precursor: 0.5 g CTAB and 1 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 30 mL deionized water, and then 1.2 mL metal impregnation solution was added. Then, 1 mL ammonia solution (28%) and 1 mL tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the phenolic resin microspheres ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 600 r / min for 18 h at room temperature. During the stirring process, tetraethyl orthosilicate and phenolic resin microspheres underwent a co-gel reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microsphere structure. At the same time, Cu metal nanoparticles were embedded in the silica layer, forming a Cu catalyst precursor supported on a C@SiO2 composite support.

[0197] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 8000 r / min for 1 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0198] (7) Drying: Wash the centrifuged product obtained in step (6) with deionized water, then add 15 mL of deionized water to the paste obtained after centrifugation to disperse it evenly, soak it for 1 hour, and then spray dry it. That is, put the paste soaked in deionized water into an atomizer, adjust the air compressor outlet pressure to 0.25 MPa to atomize it. Transfer the atomized product to the drying tower, and then adjust the air input to 3 mL. 3 Spray drying was performed at a flow rate of 8 mL / min using a peristaltic pump and an inlet air temperature of 100 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0199] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 800℃ for 5 hours under N2 atmosphere with a gas flow rate of 30 mL / min and a heating rate of 2℃ / min.

[0200] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 200°C for 2 hours under an H2 / Ar atmosphere (H2 concentration of 5%) with a gas flow rate of 30 mL / min and a heating rate of 8 °C / min. A C@SiO2 supported Cu catalyst (Cu loading of 0.3 wt%) was prepared.

[0201] (10) Add 0.01 g of catalyst and 2 g of m-chloronitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave with H2 five times. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 40 °C, start stirring at 1000 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100%.

[0202] Comparative Example 3

[0203] The catalyst preparation process of this comparative example is similar to that of Example 1, except that Cu metal impregnation solution was not prepared in step (1) and Cu metal was not loaded in step (5).

[0204] Furthermore, the preparation process of this comparative catalyst is as follows:

[0205] (1) Weigh 1.09g of PtCl4 into a 100mL volumetric flask, dilute with deionized water to the mark, and prepare a precious metal impregnation solution.

[0206] (2) Add 0.3 mL of phenol (30%), 0.75 mL of formaldehyde (30%), and 0.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser switch to allow the phenol and formaldehyde to undergo a condensation reaction at 60°C and 600 r / min for 1 hour. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0207] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 30 mL / min, heat it to 600℃ at a heating rate of 2℃ / min and keep it for 4 hours to obtain calcined microsphere-shaped phenolic resin solid spheres, which can be used as carbon source.

[0208] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 200-220 mesh.

[0209] (5) Synthesis of catalyst precursor: 0.5 g CTAB and 1 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 30 mL deionized water, and then 0.6 mL of the noble metal impregnation solution prepared in step (1) was added. Then, 1 mL of ammonia solution (28%) and 1 mL of tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the above mixture, followed by the addition of the phenolic resin microspheres ground in step (4). Then, a rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and stirred at 600 r / min for 18 h at room temperature. During the stirring process, tetraethyl orthosilicate and phenolic resin microspheres underwent a co-gel reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microsphere structure. At the same time, Pt metal nanoparticles were embedded in the silica layer, forming a Pt catalyst precursor supported on a C@SiO2 composite support.

[0210] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 8000 r / min for 1 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0211] (7) Drying: Wash the centrifuged product obtained in step (6) with deionized water, then add 15 mL of deionized water to the paste obtained after centrifugation to disperse it evenly, soak it for 1 hour, and then spray dry it. That is, put the paste soaked in deionized water into an atomizer, adjust the air compressor outlet pressure to 0.25 MPa to atomize it. Transfer the atomized product to the drying tower, and then adjust the air input to 3 mL. 3 Spray drying was performed at a flow rate of 8 mL / min using a peristaltic pump and an inlet air temperature of 100 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0212] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 800℃ for 5 hours under N2 atmosphere with a gas flow rate of 30 mL / min and a heating rate of 2℃ / min.

[0213] (9) The solid product calcined in step (8) was placed in a tube furnace and kept at 200°C for 2 hours under an H2 / Ar atmosphere (H2 concentration of 5%) with a gas flow rate of 30 mL / min and a heating rate of 8 °C / min. A C@SiO2 supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.7 wt%) was prepared.

[0214] (10) Add 0.01 g of catalyst and 1 g of m-chloronitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave with H2 five times. Then, pressurize the autoclave to 1 MPa with H2 at room temperature. Then heat the autoclave to 40 °C, start stirring at 1000 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100%.

[0215] Comparative Example 4

[0216] The Pt-Cu bimetallic content in this comparative catalyst is similar to that in Example 1. The difference is that a C@SiO2 support was first synthesized, and then the Pt-Cu bimetallic alloy was loaded onto the C@SiO2 support using a conventional impregnation method.

[0217] Furthermore, the preparation process of this comparative catalyst is as follows:

[0218] (1) Weigh 1.09g PtCl4 and 0.39g Cu(NO3)2 into 100mL volumetric flasks, dilute with deionized water to the mark, and prepare precious metal impregnation solution and metal impregnation solution.

[0219] (2) Add 0.3 mL of phenol (30%), 0.75 mL of formaldehyde (30%), and 0.5 g of Na₂CO₃ to a three-necked flask and place a rotor inside. Then, place the three-necked flask in a sand bath. Connect the three-necked flask to a straight condenser and a thermometer, and seal the remaining outlet with a glass stopper. Heat the entire system using the sand bath, and simultaneously turn on the magnetic stirrer and the condenser switch to allow the phenol and formaldehyde to undergo a condensation reaction at 60°C and 600 r / min for 1 hour. The resulting gelatinous liquid after the reaction is complete is the phenolic resin.

[0220] (3) Place the phenolic resin gel liquid synthesized in step (2) in a quartz boat and then place it in a tube furnace. Under N2 at 30 mL / min, heat it to 600℃ at a heating rate of 2℃ / min and keep it for 4 hours to obtain calcined microsphere-shaped phenolic resin solid spheres, which can be used as carbon source.

[0221] (4) Place the phenolic resin balls obtained after the first calcination in step (3) into a mortar and grind them to grind the granular phenolic resin into powder; then use a sieve to sieve the ground solid powder to 200-220 mesh.

[0222] (5) Synthesis of C@SiO2 support: 0.5 g CTAB and 1 mL 1,3,5-trimethylbenzene (TMB) were dissolved in a beaker containing 30 mL deionized water. Then, 1 mL ammonia solution (28%) and 1 mL tetraethyl orthosilicate (TEOS, 28%) were added dropwise to the mixture. The phenolic resin microspheres ground in step (4) were then added to the mixture. A rotor was added to the beaker, and the beaker containing the mixture was placed on a magnetic stirrer. The stirring reaction was started and the mixture was stirred at 600 r / min for 18 h at room temperature. During the stirring process, tetraethyl orthosilicate and phenolic resin microspheres underwent a co-gelation reaction to form a C@SiO2 composite support with a silica-encapsulated phenolic resin microsphere structure.

[0223] (6) The catalyst precursor mixture synthesized in step (5) is placed in a centrifuge and centrifuged at a speed of 8000 r / min for 1 min to achieve solid-liquid separation and obtain a paste-like solid product.

[0224] (7) Drying: Wash the centrifuged product obtained in step (6) with deionized water, then add 15 mL of deionized water to the paste obtained after centrifugation to disperse it evenly, soak it for 1 hour, and then spray dry it. That is, put the paste soaked in deionized water into an atomizer, adjust the air compressor outlet pressure to 0.25 MPa to atomize it. Transfer the atomized product to the drying tower, and then adjust the air input to 3 mL. 3 Spray drying was performed at a flow rate of 8 mL / min using a peristaltic pump and an inlet air temperature of 100 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0225] (8) Transfer the dried product from step (7) to a tube furnace, and maintain it at 800℃ for 5 hours under N2 atmosphere with a gas flow rate of 30 mL / min and a heating rate of 2℃ / min.

[0226] (9) Add the 0.6 mL noble metal impregnation solution and 1.2 mL metal impregnation solution prepared in step (1) to the C@SiO2 support synthesized in step (5), and then add 30 mL deionized water to it. Stir at a stirring rate of 600 r / min for 1 h at room temperature.

[0227] (10) Centrifuge the mixture synthesized in step (9) at a speed of 8000 r / min for 1 min to achieve solid-liquid separation. Then wash with deionized water and ethanol, and transfer it to the atomizer in a pressure spray dryer. Adjust the air compressor outlet pressure to 0.5 MPa to atomize the mixture, and then transfer the atomized product to the drying tower. Adjust the air input to 5 m³ / min.3 Spray drying was performed at a flow rate of 10 mL / min using a peristaltic pump and an inlet air temperature of 120 °C. Finally, the dried solid product was collected at the bottom of the drying tower to obtain the spray-dried catalyst precursor.

[0228] (11) Transfer the dried product from step (10) to a tube furnace, and maintain it at 500°C for 2 hours under an inert atmosphere with a gas flow rate of 30 mL / min and a heating rate of 2 °C / min.

[0229] (12) The solid product calcined in step (11) was placed in a tube furnace and kept at 200°C for 2 hours under an H2 / Ar atmosphere (H2 concentration of 5%) with a gas flow rate of 30 mL / min and a heating rate of 8 °C / min. A C@SiO2-supported Pt-Cu bimetallic alloy catalyst (Pt loading of 0.7 wt% and Cu loading of 0.3 wt%) was prepared.

[0230] (13) Add 0.01 g of catalyst and 1 g of m-chloronitrobenzene to a 50 mL autoclave. Before the reaction, purge the autoclave five times with H2. Then, pressurize the autoclave to 2 MPa with H2 at room temperature. Then heat the autoclave to 40 °C, start stirring at 1000 rpm, and analyze the selectivity of the product and record the reaction time when the conversion of the reaction substrate is 100%.

[0231]

[0232] Examples 13-19

[0233] The synthesis process of haloanilines was similar to that in Example 1, using the catalyst prepared in Example 1. The differences were in the stirring rate, the amount of catalyst and substrate, and the hydrogen pressure. This was to verify the catalyst activity, the specific reaction conditions, and the reaction time at which the conversion of reactants reached 100%. The product selectivity is shown in Table 2.

[0234]

[0235] Example 20

[0236] To test the stability of the catalyst, a cyclic reaction experiment was conducted with 1 g of m-chloronitrobenzene, 0.01 g of the catalyst prepared in Example 1, 1 MPa H2, 40 °C, and 1000 rpm, as per Example 1. The specific results are as follows: Figure 1 As shown.

Claims

1. A method for preparing a C@SiO2-supported Pt-Cu bimetallic alloy catalyst, characterized in that: The preparation method includes the following steps: (1) Preparation of impregnation solution: Platinum chloride and copper nitrate were dissolved in deionized water to prepare a precious metal impregnation solution with a concentration of PtCl4 of 4.7-27.7 mg / mL and a metal impregnation solution with a concentration of Cu(NO3)2 of 3.9-9 mg / mL. (2) Phenolic resin polymerization: A certain amount of phenol, formaldehyde and Na2CO3 are added to the reaction vessel, and a colloidal liquid is obtained through polycondensation reaction, which is phenolic resin. (3) First calcination: The phenolic resin gel liquid synthesized in step (2) is placed in a quartz boat and then placed in a tube furnace. Under an inert atmosphere of 30-50 mL / min, the temperature is raised to 600-800℃ at a heating rate of 2-4℃ / min and held for 4-6 hours to obtain microsphere-shaped phenolic resin solid spheres. These spheres are then ground and sieved to serve as a carbon source. (4) Synthesis of catalyst precursor: The template agent and 1,3,5-trimethylbenzene were dissolved in deionized water, and a certain amount of the noble metal impregnation solution and metal impregnation solution prepared in step (1) were added; then, a certain amount of ammonia solution and tetraethyl orthosilicate were added dropwise to the above mixture, and then the carbon source obtained in step (3) was added to the above mixture; then the mixture was stirred at room temperature for a period of time. During the stirring process of the whole system, tetraethyl orthosilicate and phenolic resin microspheres underwent a co-gel reaction to form a C@SiO2 composite support with silica-encapsulated phenolic resin microsphere structure. At the same time, Pt and Cu metal nanoparticles were embedded in the silica layer to form a C@SiO2 composite support loaded with Pt-Cu bimetallic catalyst precursor. (5) Centrifugation: The catalyst precursor mixture synthesized in step (4) is centrifuged to achieve solid-liquid separation and obtain a paste-like solid product; (6) Drying: The paste-like solid product obtained in step (5) is washed with deionized water, and then a certain amount of deionized water is added to the paste-like product obtained after centrifugation to make it evenly dispersed. It is then soaked for a certain time and then spray-dried to obtain the spray-dried catalyst precursor. (7) Second calcination: The catalyst precursor obtained in step (6) is heated to 800-1000℃ at a heating rate of 2-4℃ / min under an inert atmosphere of 30-50mL / min and held for 5-8h to obtain the calcined product. (8) Reduction: The product obtained by calcination in step (7) is heated to 200-400℃ under a hydrogen-argon mixture at a heating rate of 8-10℃ / min and held for 2-4h to obtain C@SiO2 supported Pt-Cu bimetallic alloy catalyst.

2. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of phenol, formaldehyde and Na2CO3 is 0.09-0.26:0.18-0.50:0.5-1.

5.

3. The preparation method according to claim 1 or 2, characterized in that: In step (2), the reaction temperature is 60-80℃, the stirring rate is 600-1000r / min, and the polycondensation reaction time is 1-3h.

4. The preparation method according to claim 1, characterized in that: In step (4), the template agent is one of CTAB, P123 and F127.

5. The preparation method according to claim 1 or 4, characterized in that: In step (4), the feeding ratio of the template agent, 1,3,5-trimethylbenzene, deionized water, ammonia, and TEOS is 0.5-1.5g: 1-3mL: 30-50mL: 1-5mL: 0.25-0.80g. The feeding of the precious metal impregnation solution and the metal impregnation solution meets the following conditions: the theoretical loading of Pt metal is 0.1-0.7wt%, and the theoretical loading of Cu metal is 0.1-0.3wt%, where the theoretical loading = m 金属 / (m 苯酚 +m 甲醛 +m 正硅酸乙酯 )×100%, m 金属 This refers to the mass of precious metals contained in a precious metal immersion solution or the mass of metals contained in a metal immersion solution.

6. The preparation method according to claim 1, characterized in that: In step (4), the stirring rate at room temperature is 600-1000 r / min, and the stirring reaction time is 18-24 h.

7. The preparation method according to claim 1, characterized in that: In step (6), the soaking time is 1-3 hours.

8. The preparation method according to claim 1, characterized in that: In step (6), the spray drying parameters are set as follows: atomization pressure of 0.25-0.8 MPa and air velocity of 3-6 m / s. 3 / h, the peristaltic pump flow rate is 8-16mL / min, and the inlet air temperature is 100-140℃.

9. A C@SiO2 supported Pt-Cu bimetallic alloy catalyst prepared by the preparation method according to any one of claims 1-8.

10. The application of the C@SiO2 supported Pt-Cu bimetallic alloy catalyst as described in claim 9 in the solventless hydrogenation of halonitrobenzene to prepare haloaniline.

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