A continuous flow method for preparing Au@Pt / C catalyst and application thereof

Abstract

The application provides a method for preparing Au@Pt / C catalyst by using a continuous flow method and application thereof, and the method is simple and efficient and can produce in one step and continuously. The method has the characteristics of high mixing efficiency, controllable ordered multiphase flow, accurate controllable reaction parameters, good reaction repeatability and high integrated automation degree, effectively solves the problems of complicated steps, long time and poor repeatability in the traditional catalyst preparation process. The continuous flow device is used to realize the accurate control of the core-shell structure. Compared with the existing preparation method and the traditional other method, the method has the advantages of rapidity, strong repeatability, strong controllability and continuous production. The prepared catalyst Au@4 ML-Pt / C can make the conversion rate of furfural to furfuryl alcohol reach 72.2%, and the selectivity of furfural is 71.0%.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of a continuous flow method for preparing a supported noble metal catalyst, in particular to a method for preparing an Au@Pt / C catalyst by a continuous flow method. BACKGROUND

[0002] The continuous flow method for preparing a catalyst is a novel technology, and the reaction occurs in a channel with a millimeter inner diameter. In chemical engineering, the continuous flow device can control key reaction parameters due to the small size of the reactor. The continuous flow reactor has many advantages, such as efficient mass and heat transfer efficiency, precise control of reaction temperature, pressure and time, easy integration and automation, and improved reaction efficiency, and therefore attracts the attention of many researchers.

[0003] The synthesis methods of general Au@Pt core-shell materials include chemical deposition, dealloying, electrodeposition, surface segregation, atomic layer deposition and physical deposition. However, the above methods still face great challenges in continuous production, batch repetition and accurate control of reaction parameters. The continuous flow method has many advantages, including enhanced heat and mass transfer, rapid and adjustable mixing of precursor solutions, continuous flow production and low reagent consumption during the entire optimization process. These characteristics promote a large number of researchers to explore the use of continuous flow devices to synthesize functional nanomaterials with higher uniformity on a large scale.

[0004] Furfuryl alcohol is an important biomass platform molecule and an important intermediate for the production of lysine, ascorbic acid (vitamin C), plasticizer, dispersant and lubricant, so it is of great significance to study the efficient conversion of furfuryl alcohol. The selective catalytic hydrogenation reaction of furfural to valuable furfuryl alcohol is one of the key ways to convert lignocellulose-based biomass into valuable fuels and fine chemicals. For many years, researchers have been focusing on how to reasonably design catalysts to increase the catalytic efficiency of furfural to furfuryl alcohol. Pt-based catalysts are widely studied in the catalytic hydrogenation of furfural due to their high catalytic activity. Pt nanoparticles-based catalysts often generate more by-products during the hydrogenation of furfural, and doping and modifying Pt-based catalysts to make them have higher furfural selectivity is one of the effective means to solve this problem. In view of the above problems, it is imperative to develop new strategies and methods for preparing catalysts to improve the conversion efficiency and selectivity of target products. SUMMARY

[0005] The application aims to provide a continuous flow method for preparing Au@Pt / C core-shell catalysts with high efficiency and easy operation and application thereof. Au nanoparticles are prepared by a continuous flow method, Pt is reduced on the surface of the Au nanoparticles by a continuous flow device to prepare Au@Pt nanoparticles, and the Au@Pt nanoparticles and activated carbon slurry are mixed in the continuous flow device. In the preparation of Au@4ML-Pt / C, the concentration of the reducing agent sodium borohydride is 0.055 mg / mL (when preparing Au nanoparticles) and 0.245 mg / mL (when preparing Au@Pt nanoparticles), which is the best, and the conversion rate of furfural to furfuryl alcohol can reach 72.2%, and the selectivity of furfural is 71.0%. The conversion rate of the Pt / C catalyst prepared by the continuous flow method and the catalyst prepared by the impregnation method is only 40.5% and 36.6%, and the selectivity of furfuryl alcohol is 30.1% and 36.4%, respectively. Compared with the above, the catalytic efficiency of the catalyst prepared by the method is improved by more than 42%, and the structure of the Au core and Pt shell also contributes to the yield of furfuryl alcohol.

[0006] To solve the technical problems of the application, the technical scheme is as follows: a method for preparing Au@Pt / C catalyst by a continuous flow method, comprising the following steps:

[0007] (1) mixing a chloroauric acid solution and a sodium citrate aqueous solution, and then reducing the mixture with a sodium borohydride aqueous solution in a continuous flow device to obtain Au nanoparticles; the mass ratio of Au to sodium borohydride is 1.2:1; the continuous flow preparation device is composed of a magnetic stirrer, a peristaltic pump, a collection device and a Teflon pipeline; the inlet end pipeline of the peristaltic pump is introduced into a container, the outlet end pipeline of the peristaltic pump is connected to a Teflon pipeline with a certain length, and finally the outlet end of the Teflon pipeline is fixed above the collection device; the collection device is a beaker; and the winding mode of the Teflon pipeline is circular;

[0008] (2) mixing a chloroplatinic acid solution and the Au nanoparticles in step (1) in a continuous flow device, and then reducing the mixture with a sodium borohydride aqueous solution to obtain Au@Pt nanoparticles; the mass ratio of Pt to sodium borohydride is 0.55:1;

[0009] (3) dispersing activated carbon in deionized water by stirring, and then obtaining activated carbon slurry by ultrasonic treatment;

[0010] (4) using activated carbon as a carrier, mixing the activated carbon slurry in step (3) and the Au@Pt nanoparticles in step (2) in a continuous flow device, and then drying the obtained suspension by suction filtration to prepare Au@Pt / C catalyst.

[0011] Preferably, the Au@Pt / C is 1wt%Au@4 ML-Pt / C catalyst, and the number of layers of the Pt shell atoms is 4.

[0012] Preferably, the Au@Pt / C is a 1 wt% Au@4 ML-Pt / C catalyst, which is prepared according to the following steps:

[0013] wherein the inner diameter of the Teflon pipeline of the continuous flow device is 3 mm;

[0014] (1) 100 mL of deionized water was measured and placed in a beaker, and then an appropriate amount of chloroauric acid was prepared into a 0.05 mg / mL aqueous solution, and an appropriate amount of sodium citrate was added, and the mass ratio of Au to sodium citrate was 1:5, and the stirring speed was 1000 rpm for 1 min; Au nanoparticles were prepared by using a continuous flow device, two pipelines were used for liquid inlet, one pipeline was used for feeding the Au precursor aqueous solution, and the other pipeline was used for feeding 100 mL of 0.042 mg / mL sodium borohydride aqueous solution prepared with ice water, and the flow rate was 15 mL / min, and the Au nanoparticles were synthesized in the Teflon pipeline through a three-way valve, and the time from the liquid entering the pipeline to flowing out was 3 min, and the prepared Au nanoparticles were stored in a refrigerator at 4°C;

[0015] (2) Au@Pt nanoparticles were prepared by using a continuous flow device, one pipeline was used for feeding the Au nanoparticle aqueous solution prepared in step (1), and the flow rate was 5 mL / min; one pipeline was used for feeding 100 mL of 0.15 mg / mL chloroplatinic acid aqueous solution, and the flow rate was 2.5 mL / min, and the two pipelines were converged through a three-way valve, and the pipeline for flowing out was used as one liquid inlet pipeline, and the other liquid inlet pipeline was 100 mL of 0.272 mg / mL sodium borohydride aqueous solution prepared with ice water, and the peristaltic pump flow rate was 7.5 mL / min, and the reduction was carried out in the Teflon pipeline through a three-way valve, and the time from the liquid entering the pipeline to flowing out was 20 min, and the prepared Au@Pt nanoparticles were collected in a beaker for waiting for loading;

[0016] (3) 1980 mg of activated carbon was taken in a beaker, 500 mL of deionized water was added, stirred at a speed of 1000 rpm for 1 min, and then ultrasonic was performed for 10 min to obtain an activated carbon slurry;

[0017] (4) Au@Pt was loaded on the activated carbon by using a continuous flow device, and two pipelines were simultaneously fed at a flow rate of 25 mL / min, one pipeline was used for feeding the Au@Pt nanoparticles prepared in step (2), and the other pipeline was used for feeding the activated carbon slurry prepared in step (3), and the two pipelines were converged through a three-way valve, and the loaded activated carbon slurry flowing out was collected in a beaker;

[0018] (5) The catalyst slurry collected in step (4) was suction filtered, and washed with deionized water until the conductivity was 0, and then the obtained solid was placed in a culture dish and dried in a vacuum drying oven at 80°C for 12 h, and after the drying was completed, the culture dish was sealed and stored, and the catalyst was named as 1 wt% Au@4 ML-Pt / C.

[0019] To solve the technical problem of the present application, another technical solution is provided: the preparation method obtains Au@Pt / C catalyst.

[0020] To solve the technical problem of the present application, another technical solution is provided: the application of the Au@Pt / C catalyst, the Au@Pt / C catalyst is used for the reaction of preparing furfuryl alcohol by furfural hydrogenation.

[0021] Preferably, the prepared platinum-based catalyst is added to the reaction kettle, the molar ratio of Pt in the catalyst to furfural is 1:1300, 1 mmoL of furfural and 8 mL of isopropyl alcohol are added, the reaction kettle is purged with 1 MPa of hydrogen for 3 times before the reaction to remove the air in the reaction kettle, 1 MPa of hydrogen is filled again, the reaction temperature is 50 DEG C, the reaction time is 1 h, after the reaction, the reaction kettle is discharged into ice water and quickly cooled to room temperature, then the catalyst and the reaction liquid are separated, the composition of the reaction liquid is detected by gas chromatography, and the reaction result is obtained.

[0022] Preferably, the platinum-based catalyst is 1wt%Au@4 ML-Pt / C, the catalyst 1wt%Au@4 ML-Pt / C is used to catalyze the preparation of furfuryl alcohol from furfural, the conversion rate of furfural is 72.2%, and the selectivity of furfuryl alcohol is 76.0%.

[0023] The present application has the following beneficial effects:

[0024] The present application provides a continuous flow preparation method of Au@Pt / C core-shell structure catalyst, the continuous flow device used can control the nucleation process of Au@Pt, the prepared particles have small particle size, narrow particle size distribution and good dispersion, and the problems of human errors such as operation method and uneven mixing are avoided, and the method is simple and efficient.

[0025] The present method respectively selects different amounts of reducing agent (sodium borohydride) added during the preparation of Au nanoparticles and Au@Pt nanoparticles, wherein in Example 4, when the concentration of the reducing agent sodium borohydride is 0.055 mg / mL (when preparing Au nanoparticles) and 0.245 mg / mL (when preparing Au@Pt nanoparticles) in the preparation of Au@4 ML-Pt / C, it is the best, which can make the conversion rate of furfural hydrogenation to prepare furfuryl alcohol reach 72.2%, and the selectivity of furfural is 71.0%, while the conversion rates of the Pt / C catalyst prepared by the continuous flow method and the catalyst prepared by the impregnation method are only 40.5% and 36.6%, and the selectivity of furfuryl alcohol is 30.1% and 36.4% respectively. In comparison, the catalyst prepared by the present method improves the catalytic efficiency by more than 42%, and the structure of Au core and Pt shell also contributes to the yield of furfuryl alcohol.

[0026] The number of Pt shell atomic layers in the catalysts prepared in Examples 1-4 is 1 ML, 2 ML, 3 ML, and 4 ML, respectively. The conversion rate of furfural and the selectivity of furfuryl alcohol of the catalyst prepared in Example 1 (1wt% Au@1 ML-Pt / C) are 71.9% and 60.5%, respectively; the conversion rate of furfural and the selectivity of furfuryl alcohol of the catalyst prepared in Example 2 (1wt% Au@2 ML-Pt / C) are 63.3% and 64.2%, respectively; the conversion rate of furfural and the selectivity of furfuryl alcohol of the catalyst prepared in Example 3 (1wt% Au@3 ML-Pt / C) are 62.7% and 63.8%, respectively; the conversion rate of furfural and the selectivity of furfuryl alcohol of the catalyst prepared in Example 4 (1wt% Au@4 ML-Pt / C) are 72.2% and 76.0%, respectively. The catalyst prepared in Example 4 has the best catalytic performance, and the yield of furfuryl alcohol is increased by more than 42% compared with the Pt / C prepared by the impregnation method and the continuous flow method. In addition, the activity and selectivity of the catalyst with Au core and Pt shell structure are better than those of the Pt / C catalyst.

[0027] The catalyst prepared by the method has good dispersion and no obvious agglomeration, while the platinum-based catalyst prepared by the impregnation method has obvious agglomeration and large particle size difference. The mechanical operation can avoid human error, making the results more repeatable and greatly improving the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic diagram of a continuous flow device

[0029] wherein Figure 1 : peristaltic pump-1; magnetic stirrer-2; Teflon tube-3;

[0030] Figure 2 is a TEM image of the Au@Pt catalyst prepared in Examples 1-4

[0031] wherein a: Example 1; b: Example 2; c: Example 3; d: Example 4

[0032] Figure 3 is a TEM image of the Au@Pt catalyst prepared in Comparative Examples 2-2, 2-4, and 2-5

[0033] wherein a: Comparative Example 2-2; b: Comparative Example 2-4; c: Comparative Example 2-5

[0034] Figure 4 is a TEM image of the Pt / C catalyst prepared by the impregnation method

[0035] Figure 5 is a HAADF-STEM and EDS image of the Au@Pt / C catalyst prepared in Example 4

[0036] Figure 6UV-Vis absorption spectrum of Au@Pt nanoparticles prepared in Example 4 DETAILED DESCRIPTION

[0037] The present application will be further described in detail by the following specific examples, which are only for illustrating the present application, but the present application is not limited to the following examples.

[0038] Example 1

[0039] The continuous flow preparation device was composed of a magnetic stirrer, a peristaltic pump, a collection device and a Teflon pipeline. The inlet end pipeline of the peristaltic pump was introduced into a container, the outlet end pipeline of the peristaltic pump was connected to a Teflon pipeline with a certain length, and the outlet end of the Teflon pipeline was finally fixed above the collection device. The collection device was a beaker, the inner diameter of the Teflon pipeline was 3 mm, and the winding mode of the Teflon pipeline was circular.

[0040] (1) 100 mL of deionized water was measured and placed in a beaker, and an appropriate amount of chloroauric acid was prepared into a 0.13 mg / mL aqueous solution, and an appropriate amount of sodium citrate (Au and sodium citrate mass ratio was 1:5) was added, and stirred at a speed of 1000 rpm for 1 min. Au nanoparticles were prepared by using a continuous flow device, two pipelines were introduced, one was introduced into the Au precursor aqueous solution, and the other was introduced into 100 mL of sodium borohydride aqueous solution with a concentration of 0.108 mg / mL prepared with ice water, and the flow rate was 15 mL / min. After converging through a three-way valve, Au nanoparticles were synthesized in the Teflon pipeline, and the time from entering the pipeline to flowing out was about 3 min, and the prepared Au nanoparticles could be stored in a refrigerator at 4°C.

[0041] (2) Au@Pt nanoparticles were prepared by using a continuous flow device, one was introduced into the Au nanoparticle aqueous solution prepared in step (1), and the flow rate was 5 mL / min; one was introduced into 100 mL of chloroplatinic acid aqueous solution with a concentration of 0.07 mg / mL, and the flow rate was 2.5 mL / min, and the pipeline flowed out was used as one of the inlet pipelines, and the other inlet pipeline was 100 mL of sodium borohydride aqueous solution with a concentration of 0.128 mg / mL prepared with ice water, and the flow rate of the peristaltic pump was 7.5 mL / min, and the liquid was reduced in the Teflon pipeline after converging through a three-way valve. The time from entering the pipeline to flowing out was 20 min, and the prepared Au@Pt nanoparticles were collected in a beaker for loading.

[0042] (3) 1980 mg of activated carbon was taken in a beaker, 500 mL of deionized water was added, stirred at a speed of 1000 rpm for 1 min, and then ultrasonic for 10 min to obtain an activated carbon slurry.

[0043] (4) Au@Pt was loaded on activated carbon by using continuous flow device, two pipes were put in liquid at the same time, one was put in Au@Pt nanoparticles prepared in step (2), the other was put in activated carbon slurry prepared in step (3), through a three-way valve to converge, and the loaded activated carbon slurry was collected in a beaker.

[0044] (5) The catalyst slurry collected in step (4) was suction filtered and washed with deionized water until the conductivity was 0. The solid obtained after suction filtration was placed in a petri dish and dried in a vacuum drying oven at 80°C for 12 h. After drying, it was sealed and stored.

[0045] The catalyst was named 1wt%Au@1 ML-Pt / C.

[0046] Example 2

[0047] The continuous flow preparation device was composed of a magnetic stirrer, a peristaltic pump, a collection device and a Teflon pipeline. The inlet end of the peristaltic pump was connected to a container, the outlet end of the peristaltic pump was connected to a length of Teflon pipeline, and the outlet end of the Teflon pipeline was finally fixed above the collection device. The collection device was a beaker, the inner diameter of the Teflon pipeline was 3 mm, and the winding mode of the Teflon pipeline was circular.

[0048] (1) 100 mL of deionized water was measured and placed in a beaker, and an appropriate amount of chloroauric acid was prepared into a 0.09 mg / mL aqueous solution, and an appropriate amount of sodium citrate (Au to sodium citrate mass ratio of 1:5) was added, and stirred at 1000 rpm for 1 min. Au nanoparticles were prepared by using a continuous flow device, two pipes were put in liquid, one was put into Au precursor aqueous solution, the other was put into 100 mL of 0.075 mg / mL sodium borohydride aqueous solution prepared with ice water, the flow rate was 15 mL / min, and the Au nanoparticles were synthesized in the Teflon pipeline through a three-way valve, the time from entering the pipeline to flowing out was about 3 min, and the prepared Au nanoparticles could be stored in the refrigerator at 4°C.

[0049] (2) Au@Pt nanoparticles were prepared by using a continuous flow device, one was put into the Au nanoparticle aqueous solution prepared in step (1) at a flow rate of 5 mL / min; the other was put into 100 mL of 0.11 mg / mL chloroplatinic acid aqueous solution at a flow rate of 2.5 mL / min, and the two were converged through a three-way valve. The outlet pipeline was used as one of the inlet pipelines, and the other inlet pipeline was 100 mL of 0.2 mg / mL sodium borohydride aqueous solution prepared with ice water, the peristaltic pump flow rate was 7.5 mL / min, and the reduction was carried out in the Teflon pipeline through a three-way valve. The time from entering the pipeline to flowing out was 20 min, and the prepared Au@Pt nanoparticles were collected in a beaker for loading.

[0050] (3) Take 1980 mg activated carbon in a beaker, add 500 mL deionized water, stir at 1000 rpm for 1 min, then ultrasonic for 10 min, to obtain activated carbon slurry.

[0051] (4) Use the continuous flow device to load Au@Pt on activated carbon, at a flow rate of 25 mL / min, two pipes are simultaneously liquid, one way into the Au@Pt nanoparticles prepared in step (2), one way into the activated carbon slurry prepared in step (3), through a three-way valve to converge, and collect the loaded activated carbon slurry flowing out with a beaker.

[0052] (5) The catalyst slurry collected in step (4) is suction filtered and washed with deionized water until the conductivity is 0, and the solid obtained after suction filtration is placed in a petri dish and put into a vacuum drying oven at 80°C for 12 h, and then sealed and stored after completion.

[0053] The catalyst is named 1wt%Au@2 ML-Pt / C.

[0054] Comparative Example 2-1

[0055] The continuous flow preparation device is composed of a magnetic stirrer, a peristaltic pump, a collection device and a Teflon pipeline; the inlet end pipeline of the peristaltic pump is introduced into the container, the outlet end pipeline of the peristaltic pump is connected to a length of Teflon pipeline, and finally the outlet end of the Teflon pipeline is fixed above the collection device. The collection device is a beaker, the inner diameter of the Teflon pipeline is 3 mm; the winding mode of the Teflon pipeline is circular.

[0056] (1) Measure 100 mL of deionized water into a beaker, then prepare a 0.09 mg / mL aqueous solution of chloroauric acid by adding an appropriate amount of sodium citrate (Au to sodium citrate mass ratio is 1:5), and stir at 1000 rpm for 1 min. Use the continuous flow device to prepare Au nanoparticles, two pipelines are liquid, one way into the Au precursor aqueous solution, one way into 100 mL of 0.075 mg / mL sodium borohydride aqueous solution prepared with ice water, the flow rate is 15 mL / min, through a three-way valve to converge, to synthesize Au nanoparticles in the Teflon pipeline, the time from liquid entering the pipeline to flowing out is about 3 min, and the prepared Au nanoparticles can be stored in a refrigerator at 4°C.

[0057] (2) Au@Pt nanoparticles were prepared by using continuous flow device. One inlet was connected with the Au nanoparticles solution prepared in step (1) with a flow rate of 5 mL / min. Another inlet was connected with 100 mL of chloroplatinic acid solution with a concentration of 0.11 mg / mL at a flow rate of 2.5 mL / min. The two inlets were converged by a three-way valve. The outlet of the Teflon tube was used as an inlet of another solution. The other inlet was connected with 100 mL of sodium borohydride solution with a concentration of 0.05 mg / mL prepared by ice water at a flow rate of 7.5 mL / min. The two inlets were converged by a three-way valve. The reduction was carried out in the Teflon tube. The time from the inlet to the outlet of the liquid was 20 min. The Au@Pt nanoparticles were collected in a beaker for loading.

[0058] (3) 1980 mg of activated carbon was taken in a beaker. 500 mL of deionized water was added. The stirring was carried out at a speed of 1000 rpm for 1 min. Then, the ultrasonic treatment was carried out for 10 min. Thus, the activated carbon slurry was obtained.

[0059] (4) Au@Pt was loaded on the activated carbon by using the continuous flow device. Two inlets were connected with the solutions at a flow rate of 25 mL / min. One inlet was connected with the Au@Pt nanoparticles prepared in step (2). The other inlet was connected with the activated carbon slurry prepared in step (3). The two inlets were converged by a three-way valve. The loaded activated carbon slurry was collected in a beaker.

[0060] (5) The catalyst slurry collected in step (4) was suction filtered. The washing was carried out with deionized water until the conductivity was 0. The solid obtained after suction filtration was placed in a petri dish. The petri dish was put into a vacuum drying oven at 80°C for drying for 12 h. After the drying was completed, the petri dish was sealed and stored.

[0061] The catalyst was named as 1wt% Au@2 ML-Pt / C (m Pt :m NaBH4 =2.2:1).

[0062] Comparative Example 2-2

[0063] The continuous flow preparation device was composed of a magnetic stirrer, a peristaltic pump, a collection device and a Teflon tube. The inlet end of the peristaltic pump was connected with a container. The outlet end of the peristaltic pump was connected with a Teflon tube. The outlet end of the Teflon tube was fixed above the collection device. The collection device was a beaker. The inner diameter of the Teflon tube was 3 mm. The winding mode of the Teflon tube was circular.

[0064] (1) Take 100 mL of deionized water into a beaker, and then take an appropriate amount of chloroauric acid to prepare a 0.09 mg / mL aqueous solution, and then add an appropriate amount of sodium citrate (the mass ratio of Au to sodium citrate is 1:5), and stir at a speed of 1000 rpm for 1 min. Use a continuous flow device to prepare Au nanoparticles. Two pipes are used for liquid input. One pipe is connected to the Au precursor aqueous solution, and the other pipe is connected to 100 mL of 0.075 mg / mL sodium borohydride aqueous solution prepared with ice water. The flow rate of both pipes is 15 mL / min. After converging through a three-way valve, Au nanoparticles are synthesized in a Teflon pipe. The time from liquid entering the pipe to flowing out is about 3 min. The prepared Au nanoparticles can be stored in a refrigerator at 4°C.

[0065] (2) Use a continuous flow device to prepare Au@Pt nanoparticles. One pipe is connected to the Au nanoparticle aqueous solution prepared in step (1), and the flow rate is 5 mL / min. One pipe is connected to 100 mL of 0.11 mg / mL chloroplatinic acid aqueous solution, and the flow rate is 2.5 mL / min. After converging through a three-way valve, the pipe for outflow is used as one pipe for liquid input, and the other pipe for liquid input is 100 mL of 0.4 mg / mL sodium borohydride aqueous solution prepared with ice water. The flow rate of the peristaltic pump is 7.5 mL / min. After converging through a three-way valve, reduction is carried out in a Teflon pipe. The time from liquid entering the pipe to flowing out is 20 min. The prepared Au@Pt nanoparticles are collected in a beaker and wait for loading.

[0066] (3) Take 1980 mg of activated carbon into a beaker, add 500 mL of deionized water, stir at a speed of 1000 rpm for 1 min, and then ultrasonic for 10 min to obtain activated carbon slurry.

[0067] (4) Use a continuous flow device to load Au@Pt onto activated carbon. Two pipes are used for liquid input at a flow rate of 25 mL / min. One pipe is connected to the Au@Pt nanoparticles prepared in step (2), and the other pipe is connected to the activated carbon slurry prepared in step (3). After converging through a three-way valve, the loaded activated carbon slurry is collected in a beaker.

[0068] (5) The catalyst slurry collected in step (4) is suction filtered, and then washed with deionized water until the conductivity is 0. The obtained solid after suction filtration is placed in a culture dish and dried in a vacuum drying oven at 80°C for 12 h. After the drying is completed, the culture dish is sealed and stored.

[0069] The catalyst is named 1wt%Au@2 ML-Pt / C (m Pt :m NaBH4 =0.275:1).

[0070] Comparative Example 2-3

[0071] The continuous flow preparation device is composed of a magnetic stirrer, a peristaltic pump, a collecting device and a Teflon pipeline; the inlet end pipeline of the peristaltic pump is introduced into a container, the outlet end pipeline of the peristaltic pump is connected to a Teflon pipeline with a certain length, and the outlet end of the Teflon pipeline is finally fixed above the collecting device. The collecting device is a beaker, and the inner diameter of the Teflon pipeline is 3 mm; the winding mode of the Teflon pipeline is circular.

[0072] (1) 100 mL of deionized water was measured and placed in a beaker, and an appropriate amount of chloroauric acid was prepared into a 0.09 mg / mL aqueous solution, and an appropriate amount of sodium citrate (Au to sodium citrate mass ratio of 1:5) was added, and stirred at a speed of 1000 rpm for 1 min. Au nanoparticles were prepared by using a continuous flow device, two pipelines were introduced, one was connected to the Au precursor aqueous solution, and the other was connected to 100 mL of sodium borohydride aqueous solution with a concentration of 0.0375 mg / mL prepared with ice water, and the flow rate was 15 mL / min. After converging through a three-way valve, Au nanoparticles were synthesized in the Teflon pipeline, and the time from entering the pipeline to flowing out was about 3 min. The prepared Au nanoparticles can be stored in a refrigerator at 4°C.

[0073] (2) Au@Pt nanoparticles were prepared by using a continuous flow device, one was connected to the Au nanoparticle aqueous solution prepared in step (1), and the flow rate was 5 mL / min; one was connected to 100 mL of chloroplatinic acid aqueous solution with a concentration of 0.11 mg / mL, and the flow rate was 2.5 mL / min. After converging through a three-way valve, the pipeline flowing out was used as a pipeline, and the other pipeline was 100 mL of sodium borohydride aqueous solution with a concentration of 0.2 mg / mL prepared with ice water, and the peristaltic pump flow rate was 7.5 mL / min. After converging through a three-way valve, reduction was carried out in the Teflon pipeline, and the time from entering the pipeline to flowing out was 20 min. The prepared Au@Pt nanoparticles were collected in a beaker and waited for loading.

[0074] (3) 1980 mg of activated carbon was taken in a beaker, 500 mL of deionized water was added, stirred at a speed of 1000 rpm for 1 min, and then ultrasonic for 10 min to obtain activated carbon slurry.

[0075] (4) Au@Pt was loaded on activated carbon by using a continuous flow device, and two pipelines were simultaneously introduced at a flow rate of 25 mL / min, one was connected to the Au@Pt nanoparticles prepared in step (2), and the other was connected to the activated carbon slurry prepared in step (3). After converging through a three-way valve, the loaded activated carbon slurry flowing out was collected with a beaker.

[0076] (5) The catalyst slurry collected in step (4) is suction filtered and washed with deionized water until the conductivity is 0. The obtained solid after suction filtration is placed in a petri dish and dried in a vacuum drying oven at 80°C for 12 h. After the end of the drying, the petri dish is sealed and stored.

[0077] The catalyst is named 1wt% Au@2 ML-Pt / C (m Au :m NaBH4 = 2.4:1).

[0078] Comparative Example 2-4

[0079] The continuous flow preparation device is composed of a magnetic stirrer, a peristaltic pump, a collection device and a Teflon pipeline. The inlet end pipeline of the peristaltic pump is introduced into a container, the outlet end pipeline of the peristaltic pump is connected to a length of Teflon pipeline, and finally the outlet end of the Teflon pipeline is fixed above the collection device. The collection device is a beaker, the inner diameter of the Teflon pipeline is 3 mm, and the winding mode of the Teflon pipeline is circular.

[0080] (1) 100 mL of deionized water is measured into a beaker, and an appropriate amount of chloroauric acid is prepared into a 0.09 mg / mL aqueous solution, and an appropriate amount of sodium citrate (Au to sodium citrate mass ratio is 1:5) is added. Stir at 1000 rpm for 1 min. Au nanoparticles are prepared using a continuous flow device. Two pipelines are used for liquid inlet, one for Au precursor aqueous solution and the other for 100 mL of 0.15 mg / mL sodium borohydride aqueous solution prepared with ice water, both at a flow rate of 15 mL / min. After converging through a three-way valve, Au nanoparticles are synthesized in the Teflon pipeline. The time from liquid entering the pipeline to flowing out is about 3 min. The prepared Au nanoparticles can be stored in a refrigerator at 4°C.

[0081] (2) Au@Pt nanoparticles are prepared using a continuous flow device. One pipeline is used for the Au nanoparticle aqueous solution prepared in step (1) at a flow rate of 5 mL / min. The other pipeline is used for 100 mL of 0.11 mg / mL chloroplatinic acid aqueous solution at a flow rate of 2.5 mL / min. After converging through a three-way valve, the pipeline for flowing out is used as one liquid inlet pipeline, and the other liquid inlet pipeline is 100 mL of 0.2 mg / mL sodium borohydride aqueous solution prepared with ice water. The peristaltic pump has a flow rate of 7.5 mL / min. After converging through a three-way valve, reduction is carried out in the Teflon pipeline. The time from liquid entering the pipeline to flowing out is 20 min. The prepared Au@Pt nanoparticles are collected in a beaker and are ready for loading.

[0082] (3) 1980 mg of activated carbon is taken in a beaker, 500 mL of deionized water is added, stirred at 1000 rpm for 1 min, and then ultrasonicated for 10 min to obtain an activated carbon slurry.

[0083] (4) Au@Pt was loaded on activated carbon by using continuous flow device, two pipes were fed simultaneously at a flow rate of 25 mL / min, one pipe was fed with Au@Pt nanoparticles prepared in step (2) and the other pipe was fed with activated carbon slurry prepared in step (3), the two pipes converged through a three-way valve, and the loaded activated carbon slurry was collected in a beaker.

[0084] (5) The catalyst slurry collected in step (4) was suction filtered and washed with deionized water until the conductivity was 0, and the obtained solid was placed in a petri dish and dried in a vacuum drying oven at 80°C for 12 h, and then sealed and stored.

[0085] The catalyst was named 1wt%Au@2 ML-Pt / C (m Au : m NaBH4 = 1.67:1).

[0086] Comparative Examples 2-5

[0087] (1) The continuous flow preparation device was composed of a magnetic stirrer, a peristaltic pump, a collection device and a Teflon pipeline. The inlet end of the peristaltic pump was connected to a container, the outlet end of the peristaltic pump was connected to a length of Teflon pipeline, and the outlet end of the Teflon pipeline was finally fixed above the collection device. The collection device was a beaker, the inner diameter of the Teflon pipeline was 3 mm, and the winding mode of the Teflon pipeline was circular.

[0088] (1) 100 mL of deionized water was measured in a beaker, and an appropriate amount of chloroauric acid was prepared into a 0.09 mg / mL aqueous solution, and an appropriate amount of sodium citrate (Au to sodium citrate mass ratio of 1:5) was added, and stirred at 1000 rpm for 1 min. Au nanoparticles were prepared by using a continuous flow device, two pipes were fed, one pipe was fed with Au precursor aqueous solution, and the other pipe was fed with 100 mL of freshly prepared 0.3 mg / mL sodium borohydride aqueous solution with ice water, the flow rate was 15 mL / min, and the Au nanoparticles were synthesized in the Teflon pipeline through a three-way valve, the time from the liquid entering the pipeline to flowing out was about 3 min, and the prepared Au nanoparticles could be stored in a refrigerator at 4°C.

[0089] (2) Au@Pt nanoparticles were prepared by using continuous flow device. One inlet was connected with the Au nanoparticles solution prepared in step (1) with a flow rate of 5 mL / min. Another inlet was connected with 100 mL of chloroplatinic acid solution with a concentration of 0.11 mg / mL at a flow rate of 2.5 mL / min. The two inlets were converged by a three-way valve. The outlet of the Teflon tube was used as an inlet of another solution. The other inlet was connected with 100 mL of sodium borohydride solution with a concentration of 0.2 mg / mL prepared by ice water at a flow rate of 7.5 mL / min. The two inlets were converged by a three-way valve. The reduction was carried out in the Teflon tube. The time from the inlet to the outlet of the liquid was 20 min. The Au@Pt nanoparticles were collected in a beaker for loading.

[0090] (3) 1980 mg of activated carbon was taken in a beaker. 500 mL of deionized water was added. The stirring was carried out at a speed of 1000 rpm for 1 min. Then, the ultrasonic treatment was carried out for 10 min. Thus, the activated carbon slurry was obtained.

[0091] (4) Au@Pt was loaded on the activated carbon by using the continuous flow device. Two inlets were connected with the solutions at a flow rate of 25 mL / min. One inlet was connected with the Au@Pt nanoparticles prepared in step (2). The other inlet was connected with the activated carbon slurry prepared in step (3). The two inlets were converged by a three-way valve. The loaded activated carbon slurry was collected in a beaker.

[0092] (5) The catalyst slurry collected in step (4) was suction filtered. The washing was carried out with deionized water until the conductivity was 0. The solid obtained after suction filtration was placed in a petri dish. The petri dish was put into a vacuum drying oven at 80°C for drying for 12 h. After the drying was completed, the petri dish was sealed and stored.

[0093] The catalyst was named as 1wt% Au@2 ML-Pt / C (m Au :m NaBH4 =1:0.3).

[0094] Example 3

[0095] The continuous flow preparation device was composed of a magnetic stirrer, a peristaltic pump, a collection device and a Teflon tube. The inlet end of the peristaltic pump was connected with a container. The outlet end of the peristaltic pump was connected with a Teflon tube. The outlet end of the Teflon tube was fixed above the collection device. The collection device was a beaker. The inner diameter of the Teflon tube was 3 mm. The winding mode of the Teflon tube was circular.

[0096] (1) Take 100 mL deionized water in a beaker, then take an appropriate amount of chloroauric acid to prepare a 0.065 mg / mL aqueous solution, add an appropriate amount of sodium citrate (Au to sodium citrate mass ratio is 1:5), and stir at 1000 rpm for 1 min. Use a continuous flow device to prepare Au nanoparticles, two pipelines are used, one is connected to the Au precursor aqueous solution, and the other is connected to 100 mL of 0.055 mg / mL sodium borohydride aqueous solution prepared with ice water, the flow rate is 15 mL / min, and the Au nanoparticles are synthesized in a Teflon pipeline after converging through a three-way valve. The time from entering the pipeline to flowing out is about 3 min, and the prepared Au nanoparticles can be stored in a refrigerator at 4°C.

[0097] (2) Use a continuous flow device to prepare Au@Pt nanoparticles, one pipeline is connected to the Au nanoparticle aqueous solution prepared in step (1), and the flow rate is 5 mL / min; one pipeline is connected to 100 mL of 0.135 mg / mL chloroplatinic acid aqueous solution, and the flow rate is 2.5 mL / min, and the other pipeline is connected to 100 mL of 0.245 mg / mL sodium borohydride aqueous solution prepared with ice water, and the flow rate is 7.5 mL / min, and the Au@Pt nanoparticles are collected in a beaker after reduction in a Teflon pipeline after converging through a three-way valve. The time from entering the pipeline to flowing out is 20 min, and the prepared Au@Pt nanoparticles are collected in a beaker for loading.

[0098] (3) Take 1980 mg of activated carbon in a beaker, add 500 mL of deionized water, stir at 1000 rpm for 1 min, and then ultrasonic for 10 min to obtain activated carbon slurry.

[0099] (4) Use a continuous flow device to load Au@Pt onto activated carbon, two pipelines are used at a flow rate of 25 mL / min, one pipeline is connected to the Au@Pt nanoparticles prepared in step (2), and the other pipeline is connected to the activated carbon slurry prepared in step (3), and the loaded activated carbon slurry is collected after converging through a three-way valve and flowing out.

[0100] (5) The catalyst slurry collected in step (4) is suction filtered and washed with deionized water until the conductivity is 0, and the solid obtained after suction filtration is placed in a petri dish and dried in a vacuum drying oven at 80°C for 12 h, and then sealed and stored.

[0101] The catalyst is named 1wt%Au@3 ML-Pt / C.

[0102] Example 4

[0103] The continuous flow preparation device is composed of a magnetic stirrer, a peristaltic pump, a collecting device and a Teflon pipeline. The inlet pipeline of the peristaltic pump is introduced into a container, the outlet pipeline of the peristaltic pump is connected to a Teflon pipeline with a certain length, and the outlet of the Teflon pipeline is finally fixed above the collecting device. The collecting device is a beaker, and the inner diameter of the Teflon pipeline is 3 mm. The winding mode of the Teflon pipeline is circular.

[0104] (1) 100 mL of deionized water was measured and placed in a beaker, and an appropriate amount of chloroauric acid was prepared into a 0.05 mg / mL aqueous solution, and an appropriate amount of sodium citrate (Au to sodium citrate mass ratio of 1:5) was added, and stirred at 1000 rpm for 1 min. Au nanoparticles were prepared by using a continuous flow device. Two pipelines were used to introduce the Au precursor aqueous solution and 100 mL of 0.042 mg / mL sodium borohydride aqueous solution prepared with ice water, and the flow rate was 15 mL / min. After converging through a three-way valve, Au nanoparticles were synthesized in the Teflon pipeline. The time from the liquid entering the pipeline to flowing out was about 3 min. The prepared Au nanoparticles can be stored in a refrigerator at 4°C.

[0105] (2) Au@Pt nanoparticles were prepared by using a continuous flow device. One pipeline was used to introduce the Au nanoparticle aqueous solution prepared in step (1), and the flow rate was 5 mL / min. One pipeline was used to introduce 100 mL of 0.15 mg / mL chloroplatinic acid aqueous solution, and the flow rate was 2.5 mL / min. After converging through a three-way valve, the pipeline flowing out was used as a pipeline for introducing liquid. The other pipeline for introducing liquid was 100 mL of 0.272 mg / mL sodium borohydride aqueous solution prepared with ice water. The flow rate of the peristaltic pump was 7.5 mL / min. After converging through a three-way valve, reduction was carried out in the Teflon pipeline. The time from the liquid entering the pipeline to flowing out was 20 min. The prepared Au@Pt nanoparticles were collected in a beaker and waited for loading.

[0106] (3) 1980 mg of activated carbon was taken in a beaker, 500 mL of deionized water was added, stirred at 1000 rpm for 1 min, and then ultrasonic was performed for 10 min to obtain an activated carbon slurry.

[0107] (4) Au@Pt was loaded on activated carbon by using a continuous flow device. Two pipelines were used to introduce liquid at a flow rate of 25 mL / min. One pipeline was used to introduce Au@Pt nanoparticles prepared in step (2), and the other pipeline was used to introduce activated carbon slurry prepared in step (3). After converging through a three-way valve, the loaded activated carbon slurry flowing out was collected by a beaker.

[0108] (5) The catalyst slurry collected in step (4) is suction filtered and washed with deionized water until the conductivity is 0. The solid obtained after suction filtration is placed in a petri dish and dried in a vacuum drying oven at 80°C for 12 h. After the end of the drying, it is sealed and stored.

[0109] The catalyst is named 1wt%Au@4 ML-Pt / C.

[0110] I. Physical property test

[0111] The catalysts prepared in Examples 1-4 and Comparative Examples 2-5 are subjected to weighing, aqua regia dissolution and dilution to constant volume, and then subjected to inductively coupled plasma optical emission spectrometer (ICP-OES) test. The results are shown in Table 1.

[0112] Table 1 ICP-OES test results of catalysts

[0113]

[0114] a The specific preparation method of the Pt / C catalyst by the continuous flow method is referred to the patent CN115850042B

[0115] b The specific preparation method of the Pt / C catalyst by the impregnation method is referred to the patent CN113999088B

[0116] According to the above results, the loading rates of the catalysts prepared in Examples 1-4, Comparative Examples 2-2, 2-4 and 2-5 are all greater than 95%, while the loading rates of the catalysts in Comparative Examples 2-1 and 2-3 are less than 90% due to the too low amount of sodium borohydride added, and the loading effect is not good.

[0117] The catalysts prepared in Examples 1-4, Comparative Examples 2-2, 2-4 and 2-5 are subjected to transmission electron microscope (TEM) characterization. The results are shown in Figure 1 The particle size statistical results are shown in Table 2.

[0118] Table 2 Particle size distribution of the catalysts prepared in Examples 1-4, Comparative Examples 2-2, 2-4 and 2-5

[0119]

[0120] According to the above results, the loading rates of the catalysts prepared in Examples 1-4, Comparative Examples 2-2, 2-4 and 2-5 are all greater than 95%, while the loading rates of the catalysts in Comparative Examples 2-1 and 2-3 are less than 90% due to the too low amount of sodium borohydride added, and the loading effect is not good. Figure 1The catalyst particles prepared in Examples 1-4 are small, have a narrow particle size distribution, are well dispersed, and have good preparation effects. In the synthesis of Au nanoparticles, the mass ratio of Au to sodium borohydride is 1.2:1, and in the synthesis of Au@Pt nanoparticles, the mass ratio of Pt to sodium borohydride is 0.55:1, which is optimal. However, in Comparative Example 2-2, the mass ratio of Pt to sodium borohydride is 0.275:1 in the synthesis of Au@Pt nanoparticles; in Comparative Examples 2-4 and 2-5, the mass ratios of Au to sodium borohydride are 1.67:1 and 3.33:1, respectively, in the synthesis of Au nanoparticles. In all of the above three comparative examples, the particles have obvious agglomeration due to the excessive amount of sodium borohydride, and the preparation effects are not good.

[0121] According to Figure 5 , the nanostructure and element distribution of the Au@4 ML-Pt / C catalyst were analyzed by HAADF-STEM. Figure 5 The HAADF-STEM image of the Au@4 ML-Pt / C catalyst and the EDS element mapping of Au (red) and Pt (green) are shown. From the EDS element mapping, it can be seen that the nanoparticles have a clear Au core and Pt shell structure, which confirms the formation of the Au@Pt core-shell structure.

[0122] According to Figure 6 , it can be seen from the UV-visible absorption spectrum that the Au nanoparticles have a clear absorption peak at 514 nm, and the Pt nanoparticles have no clear absorption peak in the range of 300-800 nm. The Au@Pt nanoparticles have almost no absorption peak in the range of 300-800 nm, which indicates that the surface of the Au nanoparticles is covered by Pt, and indirectly proves the formation of the Au@Pt core-shell structure.

[0123] Therefore, the catalysts prepared in Examples 1-4, the Pt / C catalyst prepared by the continuous flow method, and the Pt / C catalyst prepared by the impregnation method can be used for the preparation of furfuryl alcohol by hydrogenation of furfural.

[0124] II. Activity test of furfural hydrogenation to prepare furfuryl alcohol

[0125] The reaction of furfural hydrogenation to prepare furfuryl alcohol was carried out in a high-pressure reactor equipped with a thermal conductivity detector. The prepared platinum-based catalyst (the molar ratio of Pt in the catalyst to furfural was 1:1300), 1 mmol of furfural, and 8 mL of isopropyl alcohol were added to the reactor. Before the reaction, the reactor was purged with 1 MPa of hydrogen three times to remove the air in the reactor, and then 1 MPa of hydrogen was charged. The reaction temperature was 50°C, and the reaction time was 1 h. After the reaction, the reactor was placed in ice water to rapidly cool to room temperature. The catalyst and the reaction liquid were separated, and the composition of the reaction liquid was detected by gas chromatography to obtain the reaction results. The test results are shown in Table 3.

[0126] Table 3. Catalytic performance of catalysts with different Pt shell thickness in the hydrogenation of furfural to furfuryl alcohol

[0127]

[0128] The experimental results of Table 3 show the catalytic performance of catalysts with different Pt shell thickness in the hydrogenation of furfural to furfuryl alcohol, and the superiority of catalysts with Au core and Pt shell structure compared to Pt / C catalyst. The catalysts prepared in Examples 1-4 differ in the mass ratio of Au and Pt in the catalyst, that is, the atomic molar ratio of Au and Pt is not the same, and the thickness of the Pt shell in the Au@Pt nanoparticles can be adjusted by controlling the amount of Au and Pt added. The calculation method of the Pt shell thickness is shown in formula (1):

[0129]

[0130] wherein y is the number of shell layers, ML is the atomic layer thickness (for example, 1 ML represents 1 atomic layer thickness), d Au@Pt is the diameter of the Au@Pt nanoparticles in the TEM image, d Au is the diameter of the Au nanoparticles in the TEM image, d Pt is the diameter of the Pt atom.

[0131] The particle size distribution of the Au nanoparticles prepared in step (1) of Examples 1-4 is shown in Table 4.

[0132] Table 4. Particle size distribution of the Au nanoparticles prepared in step (1) of Examples 1-4

[0133]

[0134] Substituting the data in Table 2 and Table 4 into formula (1), it can be known that the number of atomic layers of the Pt shell in the catalysts prepared in Examples 1-4 is 1 ML, 2 ML, 3 ML, and 4 ML, respectively. The furfural conversion rate of the catalyst prepared in Example 1 (1wt%Au@1 ML-Pt / C) is 71.9%, and the selectivity of furfuryl alcohol is 60.5%; the furfural conversion rate of the catalyst prepared in Example 2 (1wt%Au@2 ML-Pt / C) is 63.3%, and the selectivity of furfuryl alcohol is 64.2%; the furfural conversion rate of the catalyst prepared in Example 3 (1wt%Au@3 ML-Pt / C) is 62.7%, and the selectivity of furfuryl alcohol is 63.8%; the furfural conversion rate of the catalyst prepared in Example 4 (1wt%Au@4 ML-Pt / C) is 72.2%, and the selectivity of furfuryl alcohol is 76.0%, which is the best among the catalysts prepared in Examples 1-4, and the yield of furfuryl alcohol is more than 42% higher than that of Pt / C prepared by impregnation method and continuous flow method. In addition, the activity and selectivity of the catalysts with Au core and Pt shell structure are better than those of the Pt / C catalyst.

[0135] From the above examples, the Au@Pt / C core-shell structure catalyst is prepared by using a continuous flow method, the catalyst with high loading rate and good particle dispersion is obtained by optimizing the amount of reagent, and is applied to the reaction of preparing furfuryl alcohol by furfuryl alcohol hydrogenation.

[0136] The continuous flow device used in the application can control the nucleation process of Au@Pt, and the prepared particles have small particle size, narrow particle size distribution and good dispersion.

[0137] And the prepared Au@Pt / C core-shell structure catalyst has good furfuryl alcohol hydrogenation catalytic activity, and the yield of furfuryl alcohol is obviously improved. Compared with the previous process production route, the process route of the application has simple preparation process, and the mechanical operation can effectively avoid human error, so that the required catalyst can be obtained in one step, and the production time is greatly reduced. The raw material is renewable, the catalyst has high activity, the reaction condition is mild, the energy consumption is reduced to a certain extent, it is environment-friendly, and it can effectively alleviate the global energy problem. Therefore, the application has wide application potential in industrial production.

[0138] The application is not limited to the specific technical solutions described in the above examples, and any technical solution formed by equivalent replacement is within the protection scope of the application.

Claims

1. The use of a continuous flow process for the preparation of Au@Pt / C catalyst in the reaction of furfural hydrogenation to furfuryl alcohol, characterized by the fact that: Au@Pt / C is 1wt% Au@4 ML-Pt / C catalyst, the preparation steps are as follows: (1) take 100 mL of deionized water into a beaker, then take an appropriate amount of chloroauric acid to prepare a 0.05 mg / mL aqueous solution, add an appropriate amount of sodium citrate, the mass ratio of Au to sodium citrate is 1:5, and stir at 1000 rpm for 1 min; Au nanoparticles are prepared by using a continuous flow device, two pipeline liquid is introduced, one is the Au precursor aqueous solution, and the other is 100 mL of 0.042 mg / mL sodium borohydride aqueous solution prepared with ice water, the flow rate is 15 mL / min, after converging through a three-way valve, Au nanoparticles are synthesized in a Teflon pipeline, the time from entering the pipeline to flowing out is 3 min, and the prepared Au nanoparticles are stored in a refrigerator at 4°C; wherein the inner diameter of the Teflon pipeline of the continuous flow device is 3 mm; (2) Au@Pt nanoparticles are prepared by using a continuous flow device, one way is to introduce the Au nanoparticle aqueous solution prepared in step (1), the flow rate is 5 mL / min; one way is to introduce 100 mL of 0.15 mg / mL chloroplatinic acid aqueous solution, the flow rate is 2.5 mL / min, after converging through a three-way valve, the pipeline flowing out is used as a liquid inlet pipeline, and the other liquid inlet pipeline is 100 mL of 0.272 mg / mL sodium borohydride aqueous solution prepared with ice water, the peristaltic pump flow rate is 7.5 mL / min, after converging through a three-way valve, reduction is carried out in a Teflon pipeline, the time from entering the pipeline to flowing out is 20 min, and the prepared Au@Pt nanoparticles are collected in a beaker for loading; (3) take 1980 mg of activated carbon into a beaker, add 500 mL of deionized water, stir at 1000 rpm for 1 min, and then ultrasonic for 10 min to obtain activated carbon slurry; (4) load Au@Pt onto activated carbon by using a continuous flow device, two pipelines are introduced at a flow rate of 25 mL / min, one way is to introduce Au@Pt nanoparticles prepared in step (2), and the other way is to introduce activated carbon slurry prepared in step (3), after converging through a three-way valve, the loaded activated carbon slurry flowing out is collected by a beaker; (5) the catalyst slurry collected in step (4) is suction filtered, washed with deionized water until the conductivity is 0, and then the obtained solid is placed in a culture dish and dried in a vacuum drying oven at 80°C for 12 h, after drying, the catalyst is sealed and stored, and the catalyst is named as 1wt% Au@4 ML-Pt / C; (5) 1wt% Au@4 ML-Pt / C catalyst is used for the reaction of preparing furfuryl alcohol by hydrogenation of furfural.

2. Use according to claim 1, characterized in that: The prepared platinum-based catalyst was added into a reaction kettle, the molar ratio of Pt in the catalyst to furfural was 1:1300, 1 mmoL of furfural and 8 mL of isopropyl alcohol were used, the reaction kettle was purged with 1 MPa of hydrogen for 3 times before the reaction to remove air in the reaction kettle, 1 MPa of hydrogen was filled again, the reaction temperature was 50 DEG C, the reaction time was 1 h, after the reaction, the reaction kettle was discharged into ice water and rapidly cooled to room temperature, the catalyst and the reaction liquid were separated, the composition of the reaction liquid was detected by gas chromatography, and the reaction result was obtained.

3. Use according to claim 2, characterized in that: The platinum-based catalyst was 1wt% Au@4 ML-Pt / C, the catalyst 1wt% Au@4 ML-Pt / C was used to catalyze furfural to prepare furfuryl alcohol, the conversion rate of furfural was 72.2%, and the selectivity of furfuryl alcohol was 76.0%.

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