Tungsten oxide supported palladium-silver catalyst with high specific surface area as well as preparation method and application of tungsten oxide supported palladium-silver catalyst

Abstract

The invention discloses a high-specific-surface-area tungsten oxide supported palladium-silver catalyst and a preparation method and application thereof, and relates to the technical field of ethanol fuel cell catalysis, the catalyst comprises a carrier WO3, Pd nanoparticles and Ag nanoparticles, and the lattice structure of the carrier WO3 has oxygen atom deletion. WO3 with oxygen vacancy defects is adopted as an electrocatalyst carrier, the specific surface area of the carrier is increased, and rich nucleation sites are provided for catalytic active components Pd nanoparticles and Ag nanoparticles, so that the dispersity of the active components is improved, and the effect of the catalyst on ethanol oxidation is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ethanol fuel cell catalysis, and in particular to a tungsten oxide-supported palladium-silver catalyst with a high specific surface area, a preparation method thereof, and an application thereof. Background Art

[0002] Direct ethanol fuel cells (DANs) are a clean alternative energy device, primarily due to their ease of storage, non-toxicity, and abundance, as well as their potential applications in powering portable electronic devices and transportation vehicles. However, the sluggish kinetics of the ethanol oxidation reaction necessitate the use of highly active catalysts to accelerate the process. Catalyst supports are an indispensable component of electrochemical catalysts. They not only reduce the amount of precious metal catalysts required but also ensure high dispersion of nanoparticles, thereby preventing agglomeration. Furthermore, they provide a continuous electron transfer pathway across the three-phase reaction interface of the electrodes.

[0003] The use of carbon materials as supports for the preparation of highly dispersed catalysts is a significant milestone in the development of fuel cell technology. This innovation significantly reduces the loading of precious metals on electrodes. However, carbon materials as catalyst supports can cause chemical or electrochemical corrosion, reducing the service stability of the catalyst. High catalytic stability can be achieved by using metal oxides as catalyst supports for precious metals. In addition, the strong interaction between the metal oxide and the catalytic metal changes the electronic structure of the catalytic metal, altering the adsorption characteristics of the reactant molecules on the catalytic metal surface and affecting the electrocatalytic activity of the supported precious metal.

[0004] Tungsten trioxide (WO3) has attracted much attention due to its unique electrochemical and photocatalytic properties, making it suitable as an electrocatalyst material in various fields. However, the application of WO3 in fuel cell catalysts is limited by its small specific surface area and poor electrical conductivity.

[0005] In view of this, this application is hereby filed. Summary of the Invention

[0006] The purpose of the present invention is to provide a tungsten oxide-supported palladium-silver catalyst with a high specific surface area, a preparation method thereof, and an application thereof, by using WO3 with oxygen atom deficiency as a catalyst carrier to solve the problem of small specific surface area of tungsten trioxide as an electrocatalyst carrier in the prior art.

[0007] First, an embodiment of the present invention provides a high specific surface area tungsten oxide-supported palladium-silver catalyst, comprising a carrier WO3 and Pd nanoparticles and Ag nanoparticles, wherein oxygen atoms are missing in the lattice structure of the carrier WO3.

[0008] As an optional embodiment, the total content of the Pd nanoparticles and the Ag nanoparticles is 1-10 wt %, the content of the carrier WO 3 is 90-99 wt %, and the molar ratio of the Pd nanoparticles to the Ag nanoparticles is 1:1.

[0009] Secondly, the present invention also provides a method for preparing a high specific surface area tungsten oxide-supported palladium-silver catalyst, which includes using blue WO3 nanoparticles as a carrier to support Pd nanoparticles and Ag nanoparticles. The preparation method includes the following steps: Adding H2PdCl4 aqueous solution and AgNO3 aqueous solution to blue WO3 nanoparticles, stirring and drying to obtain mixed powder; The mixed powder is subjected to a reduction reaction to reduce the Pd ions therein into Pd nanoparticles and the Ag ions into Ag nanoparticles to obtain a catalyst.

[0010] As an optional embodiment, the method for preparing the blue WO3 nanoparticles includes subjecting a tungsten source to a hydrothermal reaction to obtain first blue WO3 nanoparticles.

[0011] As an optional embodiment, the tungsten source is WCl6, and the hydrothermal reaction process includes dissolving WCl6 powder in glacial acetic acid and stirring with ultrasonic waves for 3 to 4 hours to obtain a yellow solution; The yellow solution is heated to 160-200° C. and maintained for 10-14 hours to obtain the first blue WO 3 nanoparticles.

[0012] As an optional embodiment, the method for preparing the blue WO3 nanoparticles further includes subjecting the first blue WO3 nanoparticles to a plasma reaction to obtain second blue WO3 nanoparticles, wherein the color depth of the second blue is greater than that of the first blue.

[0013] As an optional embodiment, in the plasma reaction, the plasma used is argon plasma.

[0014] As an optional implementation manner, the vacuum degree of the plasma reaction is 35~45Pa, and the reaction time is 4~6min.

[0015] As an optional embodiment, the reaction atmosphere of the reduction reaction includes hydrogen and argon, the molar fraction of the hydrogen is 4-6%, the reaction temperature is 120-200° C., and the reaction time is 2-5 h.

[0016] Finally, an embodiment of the present invention also provides an application of a high specific surface area tungsten oxide-supported palladium-silver catalyst, specifically applying the catalyst to an alcohol oxidation reaction.

[0017] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects: 1. The embodiment of the present invention uses WO3 with oxygen vacancy defects as an electrocatalyst carrier, thereby increasing the specific surface area of the carrier and providing abundant nucleation sites for the catalytically active components Pd nanoparticles and Ag nanoparticles, thereby improving the dispersibility of the active components and enhancing the catalyst's effect on ethanol oxidation.

[0018] 2. In the embodiment of the present invention, tungsten oxide with abundant oxygen defects and high specific surface area is prepared through hydrothermal reaction and / or plasma reaction. As a catalyst carrier, tungsten oxide can provide abundant nucleation sites, which is conducive to dispersing active components and reducing the use of catalytic components (precious metals).

[0019] 3. The tungsten oxide obtained in the embodiment of the present invention, due to its abundant oxygen defects and high specific surface area, can be used to obtain dispersed bimetallic nanoparticles using a simple gas reduction method, thereby obtaining higher catalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 is a SEM image of WO3 nanoparticles prepared by hydrothermal reaction in an embodiment of the present invention; Figure 2 This is a SEM image of WO3 nanoparticles prepared by hydrothermal reaction and plasma reaction in an embodiment of the present invention; Figure 3 This is the SEM image of WO3 nanoparticles obtained by hydrothermal reaction after oxidation heating; Figure 4 Comparison diagram of adsorption and desorption curves; Figure 5 This is a comparison diagram of pore distribution; Figure 6 Comparison of CV curves of PdAg / WO3, PdAg / WO3-500 and PdAg / WO3-Ar; Figure 7 Comparison of CV curves of PdAg / WO3-Ar and PdAg / C.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0025] In the description of the present invention, it should be noted that the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0026] Example The present invention provides a method for preparing a tungsten oxide-supported palladium-silver catalyst with a high specific surface area, comprising the following steps: (1) Dissolve 5-20 g WCl6 powder of tungsten source in glacial acetic acid solvent and stir ultrasonically for 3-4 hours to obtain a light yellow solution in which the concentration of glacial acetic acid is 30-95 wt%.

[0027] (2) The prepared solution was transferred to a Teflon-lined stainless steel autoclave for solvent thermal treatment. The sealed autoclave was heated to 160-200 °C in an electric oven for 10-14 h, and then the autoclave was allowed to cool slowly at room temperature.

[0028] (3) After washing with distilled water and ethanol to remove the residue, the mixture was dried in a vacuum oven at 50–70 °C for 10–14 h. WO3 nanoparticles (named WO3) with a high specific surface area and oxygen vacancies were observed. The WO3 nanoparticles obtained by the hydrothermal reaction had a certain amount of oxygen defects, thus appearing light blue.

[0029] (4) In order to further increase the specific surface area and defects of WO3 nanoparticles, WO3 was dispersed in a quartz boat and placed in a plasma reactor filled with argon. WO3 was dispersed in a quartz boat and placed in a plasma reactor filled with argon. The pressure was reduced to 35~45 Pa by vacuum suction. After 4~6 minutes of plasma treatment, the sample WO3-Ar was taken out from the plasma reactor. After Ar plasma etching, WO3 had more oxygen defects and the powder appeared dark blue.

[0030] (5) Adding H2PdCl4 aqueous solution and AgNO3 aqueous solution to WO3-Ar powder. After magnetic stirring for 5-7 hours, the mixed solution was dried in a vacuum oven at 300-350K for 10-14 hours. Then, the prepared powder was heated in a tube furnace with a temperature program set at 120-200 degrees Celsius in a hydrogen-argon mixed gas with a hydrogen molar fraction of 4-6% for 2-5 hours to obtain a catalyst. The molar ratio of the active component Pd nanoparticles to the Ag nanoparticles was 1:1, the concentration range of the H2PdCl4 aqueous solution was 0.01-0.08 mol / L, and the concentration range of the AgNO3 aqueous solution was 0.01-0.08 mol / L. The amount of the active component in the catalyst was 1-10 wt%. The amount of the carrier WO3-Ar was between 90-99 wt%.

[0031] Example 1 The present invention provides a method for preparing a tungsten oxide-supported palladium-silver catalyst with a high specific surface area, comprising the following steps: (1) Dissolve 10 g of WCl6 powder, a tungsten source, in 60 ml of glacial acetic acid. After ultrasonic stirring for 3.5 hours, a light yellow solution is obtained, in which the concentration of glacial acetic acid is 95 wt%.

[0032] (2) The prepared solution was transferred to a 100 mL Teflon-lined stainless steel autoclave for solvothermal treatment. The sealed autoclave was heated to 180 °C in an electric oven for 12 h, and then the autoclave was allowed to cool slowly at room temperature.

[0033] (3) After washing with distilled water and ethanol to remove the residue, the mixture was dried in a vacuum oven at 60 °C for 12 h. WO3 nanoparticles with a high specific surface area and oxygen vacancies (named WO3) were observed. The WO3 nanoparticles obtained by the hydrothermal reaction have a certain amount of oxygen defects, thus showing a light blue color, as shown in Figure 2. Figure 1 shown.

[0034] (4) In order to further increase the specific surface area and defects of WO3 nanoparticles, WO3 was dispersed in a quartz boat and placed in a plasma reactor filled with argon. The pressure was reduced to 40 Pa by vacuum suction. After 5 minutes of plasma treatment, the sample WO3-Ar was taken out from the plasma reactor. Figure 2 As shown, after Ar plasma etching, WO3 has more oxygen defects and the powder appears dark blue.

[0035] (5) To 140.66 mg of WO3-Ar powder, 250 μL of a 50 mmol aqueous solution of H2PdCl4 and 250 μL of a 50 mmol aqueous solution of AgNO3 were added. After magnetic stirring for 6 hours, the mixed solution was dried in a vacuum oven at 323 K for 12 hours. The prepared powder was then heated in a tube furnace with a temperature program set to 120 degrees Celsius under a mixture of hydrogen and argon with a hydrogen molar fraction of 5% for 2 hours to obtain a catalyst. The molar ratio of the active components Pd nanoparticles to Ag nanoparticles in the catalyst was 1:1, and the amount of the active component was 3 wt%. The amount of the carrier WO3-Ar was 97 wt%.

[0036] Example 2 The present invention provides a method for preparing a tungsten oxide-supported palladium-silver catalyst with a high specific surface area, comprising the following steps: (1) 5 g of WCl6 powder, a tungsten source, was dissolved in 60 ml of glacial acetic acid. After ultrasonic stirring for 3.5 hours, a light yellow solution was obtained, in which the concentration of glacial acetic acid was 30 wt%.

[0037] (2) The prepared solution was transferred to a 100 mL Teflon-lined stainless steel autoclave for solvothermal treatment. The sealed autoclave was heated to 180 °C in an electric oven for 12 h, and then the autoclave was allowed to cool slowly at room temperature.

[0038] (3) After washing with distilled water and ethanol to remove the residue, the mixture was dried in a vacuum oven at 60 °C for 12 h. WO3 nanoparticles with a high specific surface area and oxygen vacancies (named WO3) were observed. The WO3 nanoparticles obtained by the hydrothermal reaction have a certain amount of oxygen defects, thus appearing light blue.

[0039] (4) To 44.9 mg of WO3 powder, 250 μL of a 50 mmol aqueous solution of H2PdCl4 and 250 μL of a 50 mmol aqueous solution of AgNO3 were added. After magnetic stirring for 6 hours, the mixed solution was dried in a vacuum oven at 323 K for 12 hours. The prepared powder was then heated in a tube furnace with a temperature program set to 120 degrees Celsius under a mixture of hydrogen and argon with a hydrogen molar fraction of 5% for 2 hours to obtain a catalyst. The molar ratio of the active components Pd nanoparticles to Ag nanoparticles in the catalyst was 1:1, and the amount of the active component was 3 wt%. The amount of the carrier WO3 was 97 wt%.

[0040] Example 3 The present invention provides a method for preparing a tungsten oxide-supported palladium-silver catalyst with a high specific surface area, comprising the following steps: (1) Dissolve 20 g of WCl6 powder, a tungsten source, in 60 ml of glacial acetic acid. Stir ultrasonically for 3 hours to obtain a light yellow solution in which the concentration of glacial acetic acid is 95 wt%.

[0041] (2) The prepared solution was transferred to a 100 mL Teflon-lined stainless steel autoclave for solvothermal treatment. The sealed autoclave was heated to 200 °C in an electric oven for 10 h, and then the autoclave was allowed to cool slowly at room temperature.

[0042] (3) After washing with distilled water and ethanol to remove the residue, the mixture was dried in a vacuum oven at 50 °C for 14 h. WO3 nanoparticles with a high specific surface area and oxygen vacancies (named WO3) were observed. The WO3 nanoparticles obtained by the hydrothermal reaction have a certain amount of oxygen defects, thus appearing light blue.

[0043] (4) In order to further increase the specific surface area and defects of WO3 nanoparticles, WO3 was dispersed in a quartz boat and placed in a plasma reactor filled with argon. WO3 was dispersed in a quartz boat and placed in a plasma reactor filled with argon. The pressure was reduced to 35 Pa by vacuum suction. After 6 minutes of plasma treatment, the sample WO3-Ar was taken out from the plasma reactor. After Ar plasma etching, WO3 had more oxygen defects and the powder appeared dark blue.

[0044] (5) To 45.34 mg of WO3-Ar powder, 250 μL of a 10 mmol aqueous solution of H2PdCl4 and 250 μL of a 10 mmol aqueous solution of AgNO3 were added. After magnetic stirring for 5 hours, the mixed solution was dried in a vacuum oven at 300 K for 14 hours. The prepared powder was then heated in a tube furnace with a temperature program set at 200 degrees Celsius for 2 hours in a mixture of hydrogen and argon with a hydrogen molar fraction of 4% to obtain a catalyst. The molar ratio of the active components, Pd nanoparticles, to Ag nanoparticles in the catalyst was 1:1, and the amount of the active component was 1 wt%. The amount of the carrier WO3-Ar was 99 wt%.

[0045] Example 4 The present invention provides a method for preparing a tungsten oxide-supported palladium-silver catalyst with a high specific surface area, comprising the following steps: (1) Dissolve 20 g of WCl6 powder, a tungsten source, in 60 ml of glacial acetic acid. After ultrasonic stirring for 4 hours, a light yellow solution is obtained, in which the concentration of glacial acetic acid is 95 wt%.

[0046] (2) The prepared solution was transferred to a 100 mL Teflon-lined stainless steel autoclave for solvothermal treatment. The sealed autoclave was heated to 160 °C in an electric oven for 14 h, and then the autoclave was allowed to cool slowly at room temperature.

[0047] (3) After washing with distilled water and ethanol to remove the residue, the mixture was dried in a vacuum oven at 70 °C for 10 h. WO3 nanoparticles with a high specific surface area and oxygen vacancies (named WO3) were observed. The WO3 nanoparticles obtained by the hydrothermal reaction have a certain amount of oxygen defects, thus appearing light blue.

[0048] (4) In order to further increase the specific surface area and defects of WO3 nanoparticles, WO3 was dispersed in a quartz boat and placed in a plasma reactor filled with argon. WO3 was dispersed in a quartz boat and placed in a plasma reactor filled with argon. The pressure was reduced to 45 Pa by vacuum suction. After 4 minutes of plasma treatment, the sample WO3-Ar was taken out from the plasma reactor. After Ar plasma etching, WO3 had more oxygen defects and the powder appeared dark blue.

[0049] (5) To 26.78 mg of WO3-Ar powder, 250 μL of a 50 mmol aqueous solution of H2PdCl4 and 250 μL of a 50 mmol aqueous solution of AgNO3 were added. After magnetic stirring for 5 hours, the mixed solution was dried in a vacuum oven at 350 K for 10 hours. The prepared powder was then heated in a tube furnace with a temperature program set to 180 degrees Celsius for 5 hours in a mixture of hydrogen and argon with a hydrogen molar fraction of 6% to obtain a catalyst. The molar ratio of the active components Pd nanoparticles to Ag nanoparticles in the catalyst was 1:1, and the amount of the active component was 10 wt%. The amount of the carrier WO3-Ar was 90 wt%.

[0050] Comparative Example 1 Provided is a method for preparing a tungsten oxide-supported palladium-silver catalyst, comprising the following steps: (1) Dissolve 10 g of WCl6 powder, a tungsten source, in 60 ml of glacial acetic acid. After ultrasonic stirring for 3.5 hours, a light yellow solution is obtained, in which the concentration of glacial acetic acid is 95 wt%.

[0051] (2) The prepared solution was transferred to a 100 mL Teflon-lined stainless steel autoclave for solvothermal treatment. The sealed autoclave was heated to 180 °C in an electric oven for 12 h, and then the autoclave was allowed to cool slowly at room temperature.

[0052] (3) After washing with distilled water and ethanol to remove the residue, the mixture was dried in a vacuum oven at 60 °C for 12 h. WO3 nanoparticles with a high specific surface area and oxygen vacancies (named WO3) were observed. The WO3 nanoparticles obtained by the hydrothermal reaction have a certain amount of oxygen defects, thus appearing light blue.

[0053] (4) The WO3 obtained by the hydrothermal reaction was heated in a muffle furnace set at 500 °C for 2 hours to obtain completely oxidized WO3 (labeled as WO3-500), as shown in Figure 3 As shown, at this time WO3 has no oxygen defects and WO3 appears bright yellow.

[0054] (5) To 23.4 mg of WO3-500 powder, 250 μL of a 50 mmol aqueous solution of H2PdCl4 and 250 μL of a 50 mmol aqueous solution of AgNO3 were added. After magnetic stirring for 6 hours, the mixed solution was dried in a vacuum oven at 323 K for 12 hours. The prepared powder was then heated in a tube furnace with a temperature program set to 120 degrees Celsius under a mixture of hydrogen and argon with a hydrogen molar fraction of 5% for 2 hours to obtain a catalyst. The molar ratio of the active components, Pd nanoparticles, to Ag nanoparticles in the catalyst was 1:1, and the amount of the active component was 10 wt%. The amount of the carrier WO3-500 was 90 wt%.

[0055] Comparative Example 2 Provided is a method for preparing a carbon black-supported palladium-silver catalyst, comprising the following steps: To 23.4 mg of carbon black powder, 250 microliters of a 50 mmol aqueous solution of HPdCl and 250 microliters of a 50 mmol aqueous solution of AgNO were added. After 6 hours of magnetic stirring, the mixed solution was dried in a vacuum oven at 323 K for 12 hours. The prepared powder was then heated for 2 hours in a tube furnace programmed to 120 degrees Celsius under a mixture of hydrogen and argon with a molar fraction of 5% hydrogen to obtain a catalyst. The molar ratio of the active components, Pd nanoparticles, to Ag nanoparticles in the catalyst was 1:1, and the amount of the active component was 10 wt%. The amount of the carrier carbon black was 90 wt%.

[0056] From the comparison between Example 1 and Comparative Example 1, it can be seen that the morphology and structure of WO3, WO3-Ar and WO3-500 were characterized by scanning electron microscopy. Figure 1 、 Figure 2 and Figure 3 As shown in the figure, after plasma treatment, the color of WO3 changes from its original light blue to dark blue. This is due to the presence of a large number of oxygen vacancy defects on the surface, which allows the surrounding excess electrons to cause metal reduction (the metal d orbital is filled with excess electrons), thus showing the color of oxygen-deficient tungsten oxide species. In contrast, the WO3 sample particles that have been heat-treated in an air atmosphere tend to sinter and aggregate, and the color changes to bright yellow. This color change is due to the disappearance of oxygen vacancies due to complete oxidation in air.

[0057] Test results: The WO3-Ar prepared in Example 1 of the present invention, the WO3 prepared in Example 2, and the WO3-500 prepared in Comparative Example 1 were tested for adsorption and desorption using the AutosorbiQ automatic adsorption instrument from Quantachrome, USA. Test method: degassing conditions (under vacuum, adjustable from room temperature to 350°C, for 20 hours), nitrogen adsorption and desorption under liquid nitrogen conditions (-196°C), where P represents the actual pressure of nitrogen in the sample tube, and P0 represents the saturated vapor pressure of nitrogen at the test temperature. By testing the adsorption amount at different relative pressures, the adsorption isotherm (such as Figure 4 As shown in the figure), the pore volume-pore size distribution was calculated using the BJH model using the adsorption isotherm (as shown in the figure). Figure 5 shown).

[0058] Depend on Figure 4 It can be seen that the specific surface area of WO3-Ar is 210.2m 2 / g, which is higher than the specific surface area of WO3 of 180m 2 / g, the specific surface area of WO3 is much higher than that of WO3-500, which shows that WO3 generated by hydrothermal reaction has abundant oxygen vacancy defects. The oxygen vacancy defects of WO3 can be further improved by plasma reaction, thus achieving the goal of ensuring the excellent electrochemical and photocatalytic properties of tungsten trioxide while solving its defect of small specific surface area. Figure 5 It can be seen that the pore sizes of WO3, WO3-Ar, and WO3-500 are all distributed in the range of 2~5 nm, among which WO3-500 without oxygen defects has the smallest mesopore volume, indicating that plasma etching can significantly increase the mesopore volume, thereby generating more electrocatalytic exposed sites.

[0059] The activity of the catalysts prepared in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 of the present invention was tested using a Shanghai Chenhua electrochemical workstation (CHI660E). The test method included testing the catalyst by cyclic voltammetry (CV), chronoamperometry (IT) and electrochemical impedance spectroscopy (EIS) in a three-electrode system at room temperature (25±1°C). The reference electrode was mercury / mercuric oxide, and the working electrode was a glassy carbon electrode with an area of 0.196 square centimeters, loaded with 0.025 mg of catalyst. The corresponding electrochemical test was carried out in an electrolyte containing 1.0 M potassium hydroxide and 1.0 M ethanol. The test results are shown in Figure 2. Figure 6 and Figure 7 shown.

[0060] Depend on Figure 6 and Figure 7 It can be seen that the catalytic activity of each catalyst for ethanol oxidation is ranked as follows: PdAg / WO3-Ar>PdAg / WO3>PdAg / WO3-500>PdAg / C. Among them, the specific activity of the catalyst is characterized by the anodic peak current density (normalized to the palladium loading). The results show that the palladium mass specific peak current density of PdAg / WO3-Ar reaches 3580 mA•mgPd -1 , which are 2.07 times and 1.47 times higher than those of PdAg / WO3-500 and PdAg / C catalysts, respectively.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, improvements, and the like made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention. It should be noted that the structures or components illustrated in the accompanying drawings are not necessarily drawn to scale, and that descriptions of known components, processing techniques, and processes are omitted to avoid unnecessarily limiting the present invention.

Claims

1. A high specific surface area tungsten oxide supported palladium silver catalyst, characterized in that: The invention comprises a carrier WO3, Pd nanoparticles and Ag nanoparticles, wherein oxygen atoms are missing in the crystal lattice structure of the carrier WO3.

2. The high specific surface area tungsten oxide supported palladium silver catalyst according to claim 1, characterized in that: The total content of the Pd nanoparticles and the Ag nanoparticles is 1-10 wt %, the content of the carrier WO 3 is 90-99 wt %, and the molar ratio of the Pd nanoparticles to the Ag nanoparticles is 1:

1.

3. A method for preparing a high specific surface area tungsten oxide-supported palladium-silver catalyst as claimed in claim 1 or 2, characterized in that: The method comprises using blue WO3 nanoparticles as a carrier to load Pd nanoparticles and Ag nanoparticles, and the preparation method comprises the following steps: Adding H2PdCl4 aqueous solution and AgNO3 aqueous solution to blue WO3 nanoparticles, stirring and drying to obtain mixed powder; The mixed powder is subjected to a reduction reaction to reduce the Pd ions therein into Pd nanoparticles and the Ag ions into Ag nanoparticles to obtain a catalyst.

4. The method for preparing a high specific surface area tungsten oxide-supported palladium-silver catalyst according to any one of claim 3, wherein: The preparation method of the blue WO3 nanoparticles includes subjecting a tungsten source to a hydrothermal reaction to obtain first blue WO3 nanoparticles.

5. The method for preparing a high specific surface area tungsten oxide supported palladium silver catalyst according to claim 4, characterized in that: The tungsten source is WCl6, and the hydrothermal reaction process includes dissolving WCl6 powder in glacial acetic acid and stirring with ultrasonic waves for 3 to 4 hours to obtain a yellow solution; The yellow solution is heated to 160-200° C. and maintained for 10-14 hours to obtain the first blue WO 3 nanoparticles.

6. The method for preparing a high specific surface area tungsten oxide supported palladium silver catalyst according to claim 4, characterized in that: The method for preparing the blue WO3 nanoparticles further includes subjecting the first blue WO3 nanoparticles to a plasma reaction to obtain second blue WO3 nanoparticles, wherein the color depth of the second blue is greater than that of the first blue.

7. The method for preparing a high specific surface area tungsten oxide supported palladium silver catalyst according to claim 6, characterized in that: In the plasma reaction, the plasma used is argon plasma.

8. The method for preparing a high specific surface area tungsten oxide supported palladium silver catalyst according to claim 7, characterized in that: The vacuum degree of the plasma reaction is 35-45 Pa, and the reaction time is 4-6 minutes.

9. The method for preparing a high specific surface area tungsten oxide supported palladium silver catalyst according to claim 3, characterized in that: The reaction atmosphere of the reduction reaction includes hydrogen and argon, the molar fraction of the hydrogen is 4-6%, the reaction temperature is 120-200° C., and the reaction time is 2-5 hours.

10. Use of the high specific surface area tungsten oxide supported palladium silver catalyst according to claim 1 or 2, characterized in that: The method comprises applying the catalyst to an alcohol oxidation reaction.

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