P-doped carbon-coated noble metal catalyst as well as preparation method and application thereof

Abstract

The invention discloses a P-doped carbon-coated noble metal catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: complexing a noble metal and a P-containing organic ligand, washing, filtering, sequentially dispersing a metal organic coordination complex crystal and activated carbon into a carbohydrate solution, combining the metal organic coordination complex crystal, the carbohydrate and the activated carbon through a hydrothermal method, carbonizing, and completely encapsulating the metal in a carbon layer, thereby obtaining the metal organic coordination complex. And preparing the P-doped carbon-coated noble metal catalyst. The P-doped carbon-coated noble metal catalyst disclosed by the invention is used in a reaction for generating p-aminophenol through nitrobenzene hydrogenation rearrangement, and the catalyst has the advantages of simple process flow, high stability, reusability, high nitrobenzene conversion rate, high p-aminophenol selectivity and the like.

Description

Technical Field

[0001] This patent relates to a P-doped carbon-wrapped precious metal catalyst, its preparation method, and its application in the hydrogenation and rearrangement of nitrobenzene to prepare p-aminophenol. Technical Background

[0002] Para-aminophenol (PAP) is a widely used fine chemical intermediate, which can be applied to the fields of medicine, pesticides, fuels, rubber additives, photosensitive materials, etc. Among the many para-aminophenol production processes, the preparation of para-aminophenol by catalytic hydrogenation of nitrobenzene is highly competitive in the industry due to its advantages such as low cost, simple process, easy separation of products, and environmental friendliness. This method uses nitrobenzene as raw material and is carried out in two steps. The first step is the catalytic hydrogenation of nitrobenzene to generate phenylhydroxylamine intermediates, and the second step is the Bamberger rearrangement of phenylhydroxylamine by phase transfer to an acidic medium to generate para-aminophenol. Therefore, the catalyst not only needs good catalytic performance, but also needs to have good acid resistance.

[0003] Chinese patent CN101440040A proposes to use solid acid as a carrier to prepare Pt-solid acid composite catalyst to realize nitrobenzene hydrogenation to prepare p-aminophenol in aqueous solution, which has little corrosion to equipment and mild reaction conditions, but the catalyst preparation is complicated, the catalyst dosage is large, and the PAP yield is low, only 17%-83%. Chinese patent CN103553954A uses pressurized CO2 / H2O to form acid to promote nitrobenzene hydrogenation to form PHA to rearrange to PAP to form p-aminophenol, the required CO2 pressure is high, the reaction time is long, and the PAP selectivity is low. In order to solve the problems of metal leaching and catalyst deactivation, a coated catalyst is prepared for the reaction system. The coated catalyst coats the metal active site of the catalyst in a carbon layer, which is an effective means to improve the stability of the catalyst, and the interaction between the shell and the metal can promote the generation of PAP. The coated catalyst separates the metal active site from the hydrogen ions in the reaction environment, which can effectively extend the service life of the metal catalyst. Chinese patent CN115722254A prepared an in-situ encapsulated Pt@H-ASM-5 catalyst, encapsulating active metals in zeolite nanocrystals, which has good stability, but the reaction temperature is 130°C, the catalyst dosage is large, the nitrobenzene conversion rate is up to 99.8%, and the selectivity for p-aminophenol is up to 88.6%. Chinese patent CN117960225A discloses a graphite phase carbon nitride encapsulated supported precious metal catalyst, the catalyst preparation process is complex, and the selectivity for p-aminophenol is up to 85.1%. The use of surfactants in the reaction increases the difficulty of subsequent product separation.

[0004] Aiming at the problems of metal loss, rapid catalyst deactivation, low catalyst activity and poor selectivity in the selective hydrogenation of nitrobenzene to prepare p-aminophenol, the present invention invents a P-targeted doped carbon-encapsulated metal catalyst. NB:m M@PC =10-100, reaction temperature 60-120°C, reaction pressure 0.6-2.0MPa, sulfuric acid solution concentration 1.0-3.0M, nitrobenzene conversion rate 100%, p-aminophenol selectivity up to 95.42%. Summary of the invention

[0005] The purpose of the present invention is to provide a P-targeted doped carbon-coated precious metal catalyst with superior catalytic performance and acid resistance, a preparation method thereof, and an application in the hydrogenation rearrangement of nitrobenzene to produce p-aminophenol. The catalyst preparation method is simple, green and efficient.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0007] In the first part, the present invention provides a method for preparing a P-doped carbon-wrapped precious metal catalyst, comprising the following steps:

[0008] (1) dispersing a noble metal precursor solution and a P-containing organic ligand in a solvent, refluxing in a water bath at 60-90° C. with stirring for 1-5 h, filtering, separating and obtaining a noble metal organic coordination complex crystal for subsequent preparation, and recycling the mother liquor; the noble metal in the noble metal precursor is Pt, Pd, Rh or Ru;

[0009] (2) dispersing the noble metal organic coordination complex crystals prepared in step (1) in the saccharide compound solution, heating and stirring in a water bath at 30-90° C. for 0.5-2 h, to obtain sample A;

[0010] (3) adding activated carbon to the sample A obtained in step (2), heating and stirring in a water bath at 30-90° C. for 2-6 hours to obtain a sample B;

[0011] (4) transferring the sample B obtained in step (3) into a hydrothermal reactor, and subjecting it to a hydrothermal reaction at 160-200° C. for 6-10 h. After the temperature drops to room temperature, opening the hydrothermal reactor, filtering and washing the hydrothermal product, and obtaining an M@PC catalyst precursor;

[0012] (5) vacuum drying the M@PC catalyst precursor;

[0013] (6) The dried M@PC catalyst precursor is placed in a tubular furnace, and heated to 80-120°C at a heating rate of 1-20°C / min at a gas flow rate of 10-50 mL / min under an inert atmosphere, and kept warm for 1-3 h. Then, it is heated to 400-800°C at a heating rate of 1-20°C / min, and kept warm for 2-6 hours to prepare a P-doped carbon-encapsulated precious metal catalyst.

[0014] Preferably, the precious metal precursor used in step (1) is one or more of H2PtCl6·6H2O, PdCl2, RhCl3·3H2O, and RuCl3·3H2O, which are prepared into a solution, and the solution concentration is preferably 0.005-0.05g / mL. H2PtCl6, RhCl3, and RuCl3 solutions are directly prepared by dissolving the above metal precursors in water. Chloropalladic acid solution is prepared by dissolving PdCl2 in a 10wt% hydrochloric acid solution.

[0015] Preferably, the P-containing organic ligand in step (1) is triphenylphosphine.

[0016] Preferably, in step (1), n 含P有机配体 :n 贵金属 =2.0-5.0, where n 贵金属 It refers to the amount of precious metal element contained in the precious metal precursor solution.

[0017] Preferably, the solvent in step (1) is one of methanol and ethanol, and more preferably, the feed ratio of the solvent to the P-containing organic ligand is 30-800 mL / g.

[0018] Preferably, the metal organic coordination complex obtained after filtering and washing in step (1) is: bis(triphenylphosphine)platinum chloride and bis(triphenylphosphine)palladium chloride.

[0019] Preferably, in step (2), the sugar compound is one of glucose, fructose and sucrose, and the solvent in the sugar compound solution is water, wherein m 糖类化合物 :V 溶剂 =1g: 50-200mL, m 糖类聚合物(g) :m 活性炭(g) =1:5-10.

[0020] Preferably, the activated carbon in step (3) is one of coconut shell and wood activated carbon, and more preferably the activated carbon has a specific surface area greater than or equal to 800 m 2 g -1 .

[0021] Preferably, in step (3), the sample A and the activated carbon are mixed according to m 贵金属 :m 活性炭 =1:20-100 feeding, where m 贵金属 Refers to the mass of precious metal elements contained in sample A.

[0022] Preferably, the solvent used for washing in step (4) is one or more of methanol, ethanol and deionized water.

[0023] Preferably, the vacuum drying conditions in step (5) are: placing in a vacuum oven at 40-120° C. and drying for 6-14 hours.

[0024] In a second aspect, the present invention provides a P-doped carbon-wrapped precious metal catalyst prepared according to the preparation method described in the first aspect.

[0025] In the M@PC catalyst prepared by the present invention, the catalyst particle size is 3-20nm.

[0026] In a third aspect, the present invention provides an application of the P-doped carbon-encapsulated precious metal catalyst described in the second aspect in the preparation of p-aminophenol by hydrogenation and rearrangement of nitrobenzene.

[0027] In the present invention, the reaction of hydrogenating and rearranging nitrobenzene to prepare p-aminophenol is carried out in a high-pressure micro-reactor.

[0028] The specific application process is as follows: put nitrobenzene and catalyst into the polytetrafluoroethylene lining of the reactor according to a certain feed ratio, add the pre-configured sulfuric acid aqueous solution, close the reactor, replace the air in the reactor with hydrogen, ensure that the air in the reactor is completely replaced, introduce hydrogen, set the reaction temperature, and after the reactor is heated to the set reaction temperature, turn on the stirring, and after the hydrogen pressure stabilizes for 0.5-1h after the reaction, release a certain amount of hydrogen, and continue the reaction for 1-3h. After the reaction is completed, stop heating and stirring. After the temperature of the reactor drops to room temperature, release the excess gas in the reactor, filter and separate the catalyst, take a liquid sample and dilute it for product analysis.

[0029] Preferably, the reaction conditions are: reaction pressure 0.6-2.0 MPa, reaction temperature 60-120° C., and concentration of aqueous sulfuric acid solution 1-3 M; after the hydrogen pressure is stabilized for 0.5-1 h, the hydrogen pressure is released to 0.4-0.1 MPa.

[0030] As a preferred embodiment, the feed ratio m NB :m 催化剂 =10-100.

[0031] The catalyst preparation method of the present invention complexes the precious metal with the organic ligand containing P, disperses the precious metal organic coordination complex crystals and activated carbon in a saccharide compound solution in sequence after washing and filtering, combines the metal organic coordination complex crystals, saccharide compound and activated carbon by hydrothermal treatment, and completely encapsulates the metal inside the carbon layer after carbonization. Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The catalyst preparation method is simple, green, efficient, and the raw materials are easily available and low in price. The catalyst metal is complexed with the organic ligand to achieve the enrichment of heteroelements on the carbon layer structure near the metal, adjust the electron distribution between the carbon layer and the metal, and improve the catalytic performance of the catalyst.

[0033] (2) The prepared P-doped activated carbon-encapsulated precious metal catalyst has a fully encapsulated structure and has very good acid resistance and catalytic performance. The metal is coordinated with the ligand, and the strong coordination bond has a strong interaction with the metal. After carbonization, a dense carbon shell is formed to protect the metal from loss. The catalyst was used 30 times without obvious deactivation.

[0034] (3) The encapsulated catalyst effectively coordinates the hydrogenation and molecular rearrangement reaction rates of the precious metal catalyst. The conversion rate of nitrobenzene to prepare p-aminophenol can reach 100%, and the selectivity can reach 95.42%. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the TEM image of the Pt@PC catalyst prepared in Example 1.

[0036] Figure 2 This is a test diagram of the application of the Pt@PC catalyst prepared in Example 1. DETAILED DESCRIPTION

[0037] The present invention will be further described by way of specific embodiments, but the protection scope of the present invention is not limited thereto:

[0038] If no specific conditions are specified in the examples of the present invention, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be obtained by conventional technical means or purchased commercially.

[0039] The specific surface area of ​​the wood activated carbon used in Examples 1-12 is 1750 m 2 / g, the specific surface area of ​​the wood activated carbon used in Examples 13-18 is 1450m 2 / g, the specific surface area of ​​the wood activated carbon used in Examples 19-24 is 1020m 2 / g, the coconut shell activated carbon used in the embodiment has a specific surface area of ​​880m 2 / g, the activated carbon used in the comparative example is wood activated carbon with a specific surface area of ​​1750m 2 / g.

[0040] The noble metals used in the embodiment are: chloroplatinic acid hexahydrate (Aladdin, AR, Pt≥7.5%), palladium chloride (Shanghai BiDe Pharmaceutical Technology Co., Ltd., 99%).

[0041] The examples used triphenylphosphine (Shanghai Titan Technology Co., Ltd., purity ≥ 99%), nitrobenzene (Shanghai Titan Technology Co., Ltd., purity ≥ 99%), sulfuric acid (Sinopharm Group, 95-95%), ethanol (Shanghai Titan Technology Co., Ltd., analytical grade), methanol (Shanghai Titan Technology Co., Ltd., analytical grade), and deionized water.

[0042] Example 1

[0043] Take 1.8mL of chloroplatinic acid solution with a 0.05g / mL content of Pt and disperse it in 30mL of ethanol solution, add 0.3668g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 3h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30mL / min N2, kept warm for 3h, and then heated to 600°C at a heating rate of 5°C / min, and kept warm for 4h. The Pt@PC catalyst was prepared. 0.5g of Pt@PC catalyst was weighed into a beaker, and 50mL of 3.0M HCl solution was added and stirred at room temperature for 4 hours. The clear liquid was taken and AAS was measured. No metal signal was detected in the hydrochloric acid pickling solution of the catalyst.

[0044] 0.8g nitrobenzene and 0.04g catalyst were added according to the feed ratio m NB :m Pt@PC =20 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 91.44%.

[0045] Example 2

[0046] Take 6.0mL of chloroplatinic acid solution with a pt content of 0.005g / mL and disperse it in 30mL of ethanol solution, add 0.1222g of triphenylphosphine, reflux and stir in a water bath at 70℃ for 3h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 180℃ for 8h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 60℃ and dried for 12h. The dried Pt@PC precursor was placed in a tube furnace, heated to 80°C at 2°C / min under a N2 flow rate of 50 mL / min, kept warm for 2 h, and then heated to 800°C at a heating rate of 5°C / min, kept warm for 3 h. The Pt@PC catalyst was prepared.

[0047] 0.8g nitrobenzene and 0.04g catalyst were added according to the feed ratio m NB :m Pt@PC =20 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 86.21%.

[0048] Example 3

[0049] Take 3.0mL of chloroplatinic acid solution with a 0.05g / mL content of Pt and disperse it in 30mL of ethanol solution, add 0.6117g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 3h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.6g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 160℃ for 10h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash with deionized water, and obtain a Pt@PC catalyst precursor. Place the Pt@PC catalyst precursor in a vacuum oven at 40℃ and dry it for 14h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 1°C / min under a flow rate of 30 mL / min N2, kept warm for 3 h, and then heated to 800°C at a heating rate of 3°C / min, kept warm for 3 h. The Pt@PC catalyst was prepared.

[0050] 0.5g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.5M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.1MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 90.11%.

[0051] Example 4

[0052] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 30mL of ethanol solution, add 0.3202g of triphenylphosphine, reflux and stir in a water bath at 90℃ for 3h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 60℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 60℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 120℃ and dried for 6h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 10°C / min under a flow rate of 30 mL / min N2, kept warm for 3 h, and then heated to 400°C at a heating rate of 10°C / min, kept warm for 6 h. The Pt@PC catalyst was prepared.

[0053] 0.5g nitrobenzene and 0.05g catalyst were added in a feed ratio of m NB :m Pt@PC =10 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 90°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 89.52%.

[0054] Example 5

[0055] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 30mL of ethanol solution, add 0.3523g of triphenylphosphine, reflux and stir in a water bath at 70℃ for 3h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 90℃ for 1h. Add 3g of wood activated carbon and stir in a water bath at 90℃ for 5h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain a Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 20°C / min under a 30mL / min N2 flow rate, kept warm for 3h, and then heated to 600°C at a heating rate of 20°C / min, kept warm for 4h. The Pt@PC catalyst was prepared.

[0056] 0.4g nitrobenzene and 0.02g catalyst were added according to the feed ratio m NB :m Pt@PC =20 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 1h, hydrogen was released to 0.4MPa, and the reaction was continued for 2h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 88.54%.

[0057] Example 6

[0058] Take 3.0mL of chloroplatinic acid solution with a 0.05g / mL content of Pt and disperse it in 50mL of ethanol solution, add 1.0080g of triphenylphosphine, reflux and stir in a water bath at 90℃ for 3h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept warm for 3 h, and then heated to 600°C at a heating rate of 5°C / min, kept warm for 4 h. The Pt@PC catalyst was prepared.

[0059] 1.0g nitrobenzene and 0.01g catalyst were mixed in a feed ratio of m NB :m Pt@PC =100 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.5MPa pressure hydrogen was introduced. The reaction temperature was set to 60°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 1h, hydrogen was released to 0.2MPa, and the reaction was continued for 3h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 89.60%.

[0060] Example 7

[0061] Take 2.5mL Pd content 0.0365g / mL chloropalladic acid solution dispersed in 30mL ethanol solution, add 0.6202g triphenylphosphine, reflux and stir in 70℃ water bath for 3h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g glucose and dissolve it in 60mL deionized water, add complex crystals, stir in 60℃ water bath for 1h. Add 3g wood activated carbon and stir in 60℃ water bath for 5h. Then transfer to the hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash with deionized water to obtain Pd@PC catalyst precursor. Place the Pd@PC catalyst precursor in a vacuum oven at 80℃ and dry it for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30mL / min N2, kept warm for 3h, and then heated to 600°C at a heating rate of 5°C / min, kept warm for 4h. The Pd@PC catalyst was prepared. 0.5g of Pd@PC catalyst was weighed into a beaker, and 50mL of 3.0M HCl solution was added and stirred at room temperature for 4h. The clear liquid was taken and AAS was measured. No metal signal was detected in the hydrochloric acid pickling solution of the catalyst.

[0062] 1.0g nitrobenzene and 0.1g catalyst were added according to the feed ratio m NB :m Pd@PC =10 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.2MPa pressure hydrogen was introduced. The reaction temperature was set to 100°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, the hydrogen was released to 0.2MPa, and the reaction was continued for 1h. The heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 93.22%.

[0063] Example 8

[0064] Take 0.82mL of chloropalladic acid solution with a Pd content of 0.0365g / mL and disperse it in 60mL of ethanol solution, add 0.2305g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 3h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 90℃ for 0.5h. Add 3g of wood activated carbon and stir in a water bath at 90℃ for 3h. Then transfer it to a hydrothermal kettle and hydrothermally react at 180℃ for 8h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pd@PC catalyst precursor. The Pd@PC catalyst precursor is placed in a vacuum oven at 80℃ and dried for 10h. The dried Pd@PC precursor was placed in a tube furnace, heated to 120°C at 1°C / min under a 10 mL / min N2 flow rate, kept warm for 3 h, and then heated to 600°C at a heating rate of 1°C / min, kept warm for 4 h. The Pd@PC catalyst was prepared.

[0065] 0.5g nitrobenzene and 0.05g catalyst were added in a feed ratio of m NB :m Pd@PC =10 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 3.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 0.6MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 1h, the hydrogen was released to 0.1MPa, and the reaction was continued for 3h. The heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 86.50%.

[0066] Example 9

[0067] Take 4.11mL of chloropalladic acid solution with a Pd content of 0.0365g / mL and disperse it in 60mL of ethanol solution, add 1.0084g of triphenylphosphine, reflux and stir in a water bath at 70℃ for 5h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.6g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 60℃ for 2h. Then add 3g of wood activated carbon and stir in a water bath at 60℃ for 5h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pd@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 40℃ and dried for 14h. The dried Pd@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept at this temperature for 3 h, and then heated to 600°C at a heating rate of 5°C / min, kept at this temperature for 4 h. The Pd@PC catalyst was prepared.

[0068] 1.0g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pd@PC =100 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 3.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.5MPa pressure hydrogen was introduced. The reaction temperature was set to 120°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.1MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 93.18%.

[0069] Example 10

[0070] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 30mL of methanol solution, add 0.3325g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 1h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept warm for 3 h, and then heated to 800°C at a heating rate of 5°C / min, kept warm for 2 h. The Pt@PC catalyst was prepared.

[0071] 1.0g nitrobenzene and 0.02g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 3.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 2.0MPa pressure hydrogen was introduced. The reaction temperature was set to 60°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.4MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 86.48%.

[0072] Embodiment 11

[0073] Take 1.8mL of ruthenium chloride solution with a Ru content of 0.05g / mL and disperse it in 50mL of ethanol solution, add 0.9178g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 1h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.6g of glucose and dissolve it in 80mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Then add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Ru@PC catalyst precursor. The Ru@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Ru@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept at this temperature for 3 h, and then heated to 800°C at a heating rate of 5°C / min, kept at this temperature for 2 h. The Ru@PC catalyst was prepared.

[0074] 2.0g nitrobenzene and 0.04g catalyst were added in a feed ratio of m NB :m Ru@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.5M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 2.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 90.85%.

[0075] Example 12

[0076] Take 1.8mL of rhodium chloride solution with a Rh content of 0.05g / mL and disperse it in 30mL of ethanol solution, add 0.8125g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 2h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.5g of glucose and dissolve it in 80mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Rh@PC catalyst precursor. The Rh@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Rh@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept at this temperature for 3 h, and then heated to 800°C at a heating rate of 5°C / min, kept at this temperature for 2 h. Rh@PC catalyst was prepared.

[0077] 1.0g nitrobenzene and 0.02g catalyst were added according to the feed ratio m NB :m Rh@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.2MPa pressure hydrogen was introduced. The reaction temperature was set to 90°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 89.78%.

[0078] Example 13

[0079] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 30mL of methanol solution, add 0.6011g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 2h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.5g of glucose and dissolve it in 80mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept at this temperature for 2 h, and then heated to 500°C at a heating rate of 5°C / min, kept at this temperature for 5 h. The Pt@PC catalyst was prepared.

[0080] 0.5g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 90.89%.

[0081] Embodiment 14

[0082] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 30mL of methanol solution, add 0.2445g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 2h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 20mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 8h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept warm for 3 h, and then heated to 800°C at a heating rate of 5°C / min, kept warm for 2 h. The Pt@PC catalyst was prepared.

[0083] 0.5g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 2h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 91.54%.

[0084] Embodiment 15

[0085] Take 1.4mL of chloroplatinic acid solution with a pt content of 0.0367g / mL and disperse it in 50mL of ethanol solution, add 0.3190g of triphenylphosphine, reflux and stir in a water bath at 90℃ for 2h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.6g of glucose and dissolve it in 120mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 5h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 8h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 90℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 2°C / min under a N2 flow rate of 50 mL / min, kept at this temperature for 3 h, and then heated to 800°C at a heating rate of 2°C / min, kept at this temperature for 3 h. The Pt@PC catalyst was prepared.

[0086] 0.5g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 120°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 1h, hydrogen was released to 0.3MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 91.22%.

[0087] Example 16

[0088] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 50mL of methanol solution, add 0.3325g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 2h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.6g of glucose and dissolve it in 90mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 5h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept at this temperature for 3 h, and then heated to 400°C at a heating rate of 5°C / min, kept at this temperature for 6 h. The Pt@PC catalyst was prepared.

[0089] 0.5g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 0.8MPa pressure hydrogen was introduced. The reaction temperature was set to 90°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.1MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 88.54%.

[0090] Embodiment 17

[0091] Take 0.82mL of chloroplatinic acid solution with a Pt content of 0.0367g / mL and disperse it in 50mL of ethanol solution, add 0.0856g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 1h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 40mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Then add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor is placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 10°C / min under a flow rate of 50 mL / min N2, kept warm for 3 h, and then heated to 800°C at a heating rate of 10°C / min, kept warm for 5 h. The Pt@PC catalyst was prepared.

[0092] 0.6g nitrobenzene and 0.02g catalyst were added according to the feed ratio m NB :m Pt@PC =30 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 100°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, the hydrogen was released to 0.1MPa, and the reaction was continued for 2h. The heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 89.56%.

[0093] Embodiment 18

[0094] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 30mL of ethanol solution, add 0.3356g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 1h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept warm for 3 h, and then heated to 800°C at a heating rate of 5°C / min, kept warm for 2 h. The Pt@PC catalyst was prepared.

[0095] 0.5g nitrobenzene and 0.05g catalyst were added in a feed ratio of m NB :m Pt@PC =10 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 0.6MPa pressure hydrogen was introduced. The reaction temperature was set to 60°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.1MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 92.55%.

[0096] Embodiment 19

[0097] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 50mL of ethanol solution, add 0.2866g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 1h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.6g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 1°C / min under a 10 mL / min N2 flow rate, kept warm for 3 h, and then heated to 600°C at a heating rate of 1°C / min, kept warm for 6 h. The Pt@PC catalyst was prepared.

[0098] 1.0g nitrobenzene and 0.02g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.1MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 90.36%.

[0099] Embodiment 20

[0100] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 30mL of ethanol solution, add 0.3325g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 1h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.6g of glucose and dissolve it in 120mL of deionized water, add the complex crystals, and stir in a water bath at 90℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 90℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept at this temperature for 3 h, and then heated to 400°C at a heating rate of 5°C / min, kept at this temperature for 6 h. The Pt@PC catalyst was prepared.

[0101] 0.5g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 60°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.1MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 89.65%.

[0102] Embodiment 21

[0103] Take 2.47mL of chloropalladic acid solution with a Pd content of 0.0365g / mL and disperse it in 40mL of methanol solution, add 1.0112g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 1h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.6g of glucose and dissolve it in 90mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Then add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pd@PC catalyst precursor. The Pd@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pd@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept warm for 3 h, and then heated to 550°C at a heating rate of 5°C / min, kept warm for 4 h. The Pd@PC catalyst was prepared.

[0104] 0.5g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pd@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 3h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 90.54%.

[0105] Embodiment 22

[0106] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 60mL of methanol solution, add 0.4502g of triphenylphosphine, reflux and stir in a water bath at 80℃ for 2h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.4g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 180℃ for 10h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 120℃ and dried for 8h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept at this temperature for 3 h, and then heated to 600°C at a heating rate of 5°C / min, kept at this temperature for 5 h. The Pt@PC catalyst was prepared.

[0107] 0.5g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.5M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 70°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.1MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 88.65%.

[0108] Embodiment 23

[0109] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 40mL of ethanol solution, add 0.2985g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 2h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.4g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 180℃ for 10h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept at this temperature for 3 h, and then heated to 600°C at a heating rate of 5°C / min, kept at this temperature for 5 h. The Pt@PC catalyst was prepared.

[0110] 1.5g nitrobenzene and 0.03g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 2.0MPa pressure hydrogen was introduced. The reaction temperature was set to 90°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.1MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 89.42%.

[0111] Embodiment 24

[0112] Take 1.8mL of chloroplatinic acid solution with a Pt content of 0.05g / mL and disperse it in 100mL of ethanol solution, add 0.5425g of triphenylphosphine, reflux and stir in a water bath at 70℃ for 2h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.3g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Then add 3g of wood activated carbon and stir in a water bath at 30℃ for 4h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 6h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor is placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept warm for 3 h, and then heated to 800°C at a heating rate of 5°C / min, kept warm for 2 h. The Pt@PC catalyst was prepared.

[0113] 1.0g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pt@PC =100 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.6MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 2h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 95.42%.

[0114] Embodiment 25

[0115] Take 3.0mL of chloroplatinic acid solution with a 0.03g / mL content of Pt and disperse it in 80mL of ethanol solution, add 0.3254g of triphenylphosphine, reflux and stir in a water bath at 60℃ for 1h, filter, separate the crystals for subsequent preparation, and the mother liquor is used for recycling. Take 0.4g of glucose and dissolve it in 60mL of deionized water, add the complex crystals, and stir in a water bath at 30℃ for 2h. Add 3g of coconut shell activated carbon and stir in a water bath at 30℃ for 6h. Then transfer it to a hydrothermal kettle and hydrothermally react at 200℃ for 10h. After cooling to room temperature, open the hydrothermal kettle, filter the hydrothermal product, wash it with deionized water, and obtain the Pt@PC catalyst precursor. The Pt@PC catalyst precursor was placed in a vacuum oven at 80℃ and dried for 10h. The dried Pt@PC precursor was placed in a tube furnace, heated to 120°C at 5°C / min under a flow rate of 30 mL / min N2, kept at this temperature for 1 hour, and then heated to 700°C at a heating rate of 5°C / min, kept at this temperature for 3 hours. The Pt@PC catalyst was prepared.

[0116] 0.5g nitrobenzene and 0.01g catalyst were added according to the feed ratio m NB :m Pt@PC =50 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 2.0M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, the hydrogen was released to 0.1MPa, and the reaction was continued for 1h. The heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 90.36%.

[0117] Embodiment 26

[0118] The application performance of the P-doped activated carbon-coated noble metal catalyst prepared in Example 1 in the hydrogenation and rearrangement of nitrobenzene to prepare p-aminophenol was investigated. The reaction conditions were the same as in Example 1. The results were as follows: Figure 2 shown.

[0119] Comparative Example 1

[0120] Take 3.0g of wood activated carbon dried at 120℃, stir in a water bath at 50℃ for 30min, add 2.4mL of newly prepared chloroplatinic acid solution with a Pt content of 0.0375g / mL, stir in a water bath at 50℃ for 2h, let stand, adjust pH=8 with NaOH, filter, transfer to a reactor, add 30mL of deionized water, fill with 1.00MPa H2, and reduce for 2h at a reaction temperature of 90℃ and a stirring speed of 1200r / min. After reduction, cool and filter to obtain a Pt / C catalyst. Weigh 0.5g of Pt / C catalyst in a beaker, add 50mL of 3.0M HCl solution, stir at room temperature for 4 hours, take the clear liquid, measure AAS, and the metal leaching rate in the catalyst is 26.75wt%.

[0121] 1g nitrobenzene and 0.05g catalyst were added according to the feed ratio m NB :m Pt@PC =20 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.5M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the reaction was completed, heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 45.77%.

[0122] Comparative Example 2

[0123] Take 3.0g of wood activated carbon dried at 120℃, stir in a water bath at 50℃ for 30min, add 4.0mL of chloroplatinic acid solution with 0.0375g / mL of Pt, stir in a water bath at 50℃ for 2h, let stand, adjust pH=8 with NaOH, filter, transfer to a reactor, add 30mL of deionized water, fill with 1.00MPa H2, and reduce for 2h at a reaction temperature of 90℃ and a stirring speed of 1200r / min. After reduction, cool and filter to obtain Pt / C catalyst.

[0124] 1g nitrobenzene and 0.05g catalyst were added according to the feed ratio m NB :m Pt@PC=20 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.5M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the reaction was completed, heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 60.25%.

[0125] Comparative Example 3

[0126] P-doped activated carbon was prepared by impregnation method. 0.3668 g of triphenylphosphine was dispersed in 30 mL of ethanol, and 3.0 g of wood activated carbon was added after complete dissolution. After ultrasonic treatment for half an hour, it was dried in a forced air oven at 120 ° C for 2 hours, and kept at 550 ° C for 4 hours under a nitrogen atmosphere, with a heating rate of 5 ° C / min. P-doped activated carbon carrier (PC) was prepared.

[0127] Take 1.0g PC carrier, stir in a water bath at 50℃ for 30min, add 0.8mL Pt chloroplatinic acid solution with 0.0375g / mL, stir in a water bath at 50℃ for 2h, let stand, adjust pH to 8 with NaOH, filter, transfer to a reactor, add appropriate amount of deionized water, fill with 1.00MPa H 2， The reduction was carried out at a reaction temperature of 90°C and a stirring speed of 1200 r / min for 2 h. After the reduction, the product was cooled and filtered to obtain Pt / PC.

[0128] 1g nitrobenzene and 0.05g catalyst were added according to the feed ratio m NB :m Pt@PC =20 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.5M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 78.22%.

[0129] Comparative Example 4

[0130] Dissolve 4g glucose in 40mL deionized water, add 1g Pt / C prepared in Comparative Example 1, stir at room temperature for 2 hours, place in a hydrothermal kettle, hydrothermal at 200℃ for 6 hours, rinse with deionized water after cooling, and dry at 60℃ under vacuum for 12h to obtain Pt / C@GLU. Raise the temperature to 120℃ at 5℃ / min under 30mL / min N2 flow rate, keep warm for 3h, and then heat to 600℃ at a heating rate of 5℃ / min, and keep warm for 4h. The catalyst Pt / C@C is obtained.

[0131] 0.8g nitrobenzene and 0.04g catalyst were added according to the feed ratio m NB :m Pt@PC =20 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.5M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 55.26%.

[0132] Comparative Example 5

[0133] 0.8 g nitrobenzene and 0.04 g commercial 3 wt% Pt / C catalyst were added at a feed ratio of m NB :m Pt@PC =20 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.5M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, excess gas was released. The catalyst was separated by filtration, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 24.08%.

[0134] Comparative Example 6

[0135] Take 3.0g of wood activated carbon dried at 120℃, stir in a water bath at 50℃ for 30min, add a newly prepared 2.4mL chloropalladic acid solution with a Pd content of 0.0375g / mL, stir in a water bath at 50℃ for 2h, let stand, adjust pH to 8 with NaOH, filter, transfer to a reactor, add an appropriate amount of deionized water, and fill with 1.00MPaH2， The reduction was carried out at a reaction temperature of 90°C and a stirring speed of 1200 r / min for 2 h. After the reduction, the mixture was cooled and filtered to obtain a Pd / C catalyst.

[0136] 0.8g nitrobenzene and 0.04g catalyst were added according to the feed ratio m NB :m Pt@PC =20 was put into the polytetrafluoroethylene lining of the reactor, 25mL of 1.5M sulfuric acid solution was added, the reactor was sealed, and the air in the reactor was replaced with hydrogen. After ensuring that the air in the reactor was completely replaced, 1.0MPa pressure hydrogen was introduced. The reaction temperature was set to 80°C. After the reactor was heated to the set reaction temperature, stirring was turned on and the speed was 1200r / min. After the hydrogen pressure of the reaction was stable for 0.5h, hydrogen was released to 0.2MPa, and the reaction was continued for 1h. Heating and stirring were stopped. After the temperature of the reactor dropped to room temperature, the excess gas in the reactor was released, the catalyst was filtered and separated, and the liquid sample was diluted for product analysis. The NB conversion rate was 100%, and the selectivity for aminophenol was 27.08%.

Claims

1. A method for preparing a P-doped carbon-wrapped noble metal catalyst, characterized in that: The preparation method comprises the following steps: (1) dispersing a noble metal precursor solution and a P-containing organic ligand in a solvent, refluxing and stirring in a water bath at 60-90° C. for 1-5 hours, filtering, separating and obtaining a noble metal organic coordination complex crystal for subsequent preparation, and recycling the mother liquor; the noble metal in the noble metal precursor is Pt, Pd, Rh or Ru; (2) dispersing the noble metal organic coordination complex crystals prepared in step (1) in the saccharide compound solution, heating and stirring in a water bath at 30-90° C. for 0.5-2 h, to obtain sample A; (3) adding activated carbon to the sample A obtained in step (2), heating and stirring in a water bath at 30-90° C. for 2-6 hours to obtain a sample B; (4) transferring the sample B obtained in step (3) into a hydrothermal reactor, and subjecting it to a hydrothermal reaction at 160-200° C. for 6-10 h. After the temperature drops to room temperature, opening the hydrothermal reactor, filtering and washing the hydrothermal product, and obtaining an M@PC catalyst precursor; (5) vacuum drying the M@PC catalyst precursor; (6) The dried M@PC catalyst precursor is placed in a tubular furnace, and heated to 80-120°C at a heating rate of 1-20°C / min at a gas flow rate of 10-50 mL / min under an inert atmosphere, and kept warm for 1-3 h. Then, it is heated to 400-800°C at a heating rate of 1-20°C / min, and kept warm for 2-6 hours to prepare a P-doped carbon-encapsulated precious metal catalyst.

2. The preparation method according to claim 1, characterized in that: The precious metal precursor used in step (1) is one or more of H2PtCl6·6H2O, PdCl2, RhCl3·3H2O, and RuCl3·3H2O.

3. The preparation method according to claim 1, characterized in that: The P-containing organic ligand in step (1) is triphenylphosphine.

4. The preparation method according to claim 1, characterized in that: In step (1), n 含P有机配体 :n 贵金属 =2.0-5.0, wherein n refers to the amount of the noble metal element contained in the noble metal precursor solution.

5. The preparation method according to claim 1, characterized in that: The solvent described in step (1) is one of methanol and ethanol.

6. The preparation method according to claim 1, characterized in that: In step (2), the sugar compound is one of glucose, fructose and sucrose, and the solvent in the sugar compound solution is water, wherein m 糖类化合物 :V 溶剂 =1g: 50-200mL, m 糖类聚合物(g) :m 活性炭(g) =1:5-10.

7. The preparation method according to claim 1, characterized in that: The activated carbon described in step (3) is one of coconut shell and wood activated carbon, and the specific surface area of ​​the activated carbon is greater than or equal to 800m 2 g -1 .

8. The preparation method according to claim 1, characterized in that: In step (3), the sample A and the activated carbon are mixed according to m 贵金属 :m 活性炭 =1:20-100 feeding, where m 贵金属 Refers to the mass of precious metal elements contained in sample A.

9. A P-doped carbon-wrapped noble metal catalyst prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the P-doped carbon-wrapped noble metal catalyst as claimed in claim 9 in the preparation of p-aminophenol by hydrogenation rearrangement of nitrobenzene.

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