WC-coated Cu / M composite material and preparation and application thereof
By preparing and optimizing the structure of WC@Cu/M composite materials, the problem of insufficient surface roughness of WC-Cu materials was solved, achieving good dispersion of noble metals, improving catalytic performance and reducing costs, making it suitable for synergistic hydrogen production via glycerol electro-oxidation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG UNIV OF TECH
- Filing Date
- 2025-11-05
- Publication Date
- 2026-05-12
AI Technical Summary
The existing WC-Cu material has insufficient surface roughness, resulting in low specific surface area and insufficient mass transfer efficiency of reactants, which seriously restricts its catalytic activity in the synergistic hydrogen production of glycerol by electro-oxidation. Traditional noble metal catalysts have high dosage, high cost, and unsatisfactory catalytic performance.
By preparing core-shell structured nanoscale WC@Cu particles and subjecting them to micro-oxidation treatment, followed by noble metal replacement on the Cu surface, a WC@Cu/M composite material was formed. The structure and component ratio were optimized to achieve good dispersion of noble metals on the carrier surface.
The catalytic performance of WC@Cu/M composite material in synergistic hydrogen production by electro-oxidation of glycerol was improved, the amount of precious metals used and the preparation cost were reduced, and the activity and stability of the catalyst were enhanced.
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Abstract
Description
Technical Field
[0001] This invention relates to a WC@Cu / M composite material, its preparation method, and its application as an electrocatalyst in the synergistic hydrogen production from glycerol electro-oxidation. Background Technology
[0002] Biomass-derived glycerol (GLY) is a low-cost byproduct of biodiesel, soap production, and processing. Its oxidation reaction (GOR) is an ideal substitute for the oxygen evolution reaction (OER) because its theoretical redox potential is lower than 0.003 V and lower than the reactive oxygen species (RHE) compared to OER. Furthermore, as an excellent bio-platform molecule, it can be converted into a series of value-added C3-C1 products. The activity and selectivity of GOR largely depend on the intrinsic properties of the electrocatalyst. Noble metal-based electrocatalysts, through alloying, heteroatom doping, and nanostructure engineering, have been widely reported for GOR due to their good corrosion resistance and low onset potential. However, this process involves a complex 12-electron transfer pathway, facing three major bottlenecks: high C / C bond breaking energy barriers, CO* poisoning of active sites by intermediates, and alkaline dissolution of the catalyst. While traditional Pt / C catalysts possess some activity, their poor selectivity for C / C bonds and the high noble metal content (over 20 wt%) severely limit their industrial application.
[0003] Tungsten carbide (WC) has been widely studied as a substitute for platinum group metal catalysts due to its platinum-like electronic structure, high electrical conductivity, and excellent chemical stability. Especially in electrocatalytic reactions such as hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), WC exhibits significant cost advantages and environmental tolerance. However, traditional WC powders have limited specific surface area, low density of surface active sites, and their smooth surface leads to insufficient mass transfer efficiency, severely limiting their catalytic activity.
[0004] Tungsten carbide-copper (WC-Cu) composites combine the platinum-like electronic properties of WC (d-band center -2.8 eV) with the excellent electrical conductivity of copper (5.96 × 10⁻⁶ eV). 7 S / m) is an ideal alternative carrier. However, the surface roughness of existing WC-Cu materials is less than 50 nm, and the specific surface area is generally less than 15 m² / g. The dense copper layer further hinders the contact of reactants with the underlying WC active sites, making it difficult to release intrinsic activity.
[0005] The paper [Zhao-Yang Chen, Chun-An Ma, You-Qun Chu, Jia-Mei Jin, Xiao Lin, Christopher Hardacreb and Wen-Feng Lin. WC@meso-Pt core–shell nanostructures for fuel cells. Chem. Commun., 2013, 49, 11677--11679] prepared a core-shell WC@meso-Pt nanocatalyst. The process involved mixing a micron-sized ammonium metatungstate hydrate precursor with copper nitrate via spray drying, followed by self-decomposition into nano-sized WC@Cu particles in a temperature-programmed gas-solid reaction, and then performing a platinum substitution reaction to synthesize the core-shell WC@meso-Pt nanocatalyst. This mesoporous nanocomposite material exhibited higher activity and stability for methanol electro-oxidation than commercial Pt / C catalysts. However, the catalytic performance of this core-shell WC@meso-Pt nanocatalyst in the synergistic hydrogen production from the electro-oxidation of glycerol was not ideal.
[0006] To address the aforementioned technical bottlenecks, this invention provides a WC@Cu / M composite material suitable for synergistic hydrogen production via electro-oxidation of glycerol and its preparation method. Summary of the Invention
[0007] The first technical problem to be solved by the present invention is to provide a method for preparing WC@Cu / M composite material. The composite material prepared by this method has stable bonding between its components, good thermal stability, and the particle size of the composite material can be controlled at the nanometer to micrometer level to adapt to different application environments.
[0008] The second technical problem to be solved by the present invention is to provide a WC@Cu / M composite material.
[0009] The third technical problem to be solved by the present invention is to provide the application of the WC@Cu / M composite material as an electrocatalyst in the synergistic hydrogen production by electro-oxidation of glycerol.
[0010] The technical solution of the present invention will be described in detail below.
[0011] In a first aspect, the present invention provides a method for preparing a WC@Cu / M composite material, wherein M is a noble metal, and the preparation method includes the following steps:
[0012] (1) Nanoscale WC@Cu particles were obtained, wherein the weight ratio of Cu to W was 1:3-10; the particles had a core-shell structure with WC as the core and Cu as the shell.
[0013] (2) Place the nano-sized WC@Cu particles in a muffle furnace and oxidize them in air at 280-300℃ for 20-40 min to obtain oxidized WC@Cu particles;
[0014] (3) The oxidized WC@Cu particles are placed in a solution containing compound M to carry out a displacement reaction, so that the mass ratio of the displacement M to the mass of the oxidized WC@Cu particles is 1-10:100. Then, solid-liquid separation and drying are performed to obtain WC@Cu / M composite material.
[0015] In this invention, M is preferably platinum or palladium.
[0016] In step (1) of this invention, the weight ratio of Cu to W in the nanoscale WC@Cu particles is 1:3-10, preferably 1:3-5, and more preferably 1:4. The nanoscale WC@Cu particles can be prepared according to methods reported in existing literature (such as the papers mentioned in the background section), i.e., first obtaining a mixed solution of copper nitrate and ammonium metatungstate, drying it to obtain a solid precursor, and then carbonizing the solid precursor in a tube furnace under a hydrogen-rich atmosphere to prepare nanoscale WC@Cu particles. Drying methods include spray drying and oven drying. The mixed solution of copper nitrate and ammonium metatungstate is prepared according to a Cu:W weight ratio of 1:3-10, preferably 1:3-5, and more preferably 1:4. The hydrogen-rich atmosphere is a mixture of H2 and CO in a volume ratio of 1:1-5, with a total volumetric flow rate of 80-160 mL / min. The carbonization conditions are as follows: the temperature is increased to 500-700 ℃ at a programmed heating rate of 3-7 ℃ / min, held for 1-2 hours, and then increased to 800-1000 ℃ at a programmed heating rate of 3-5 ℃ / min, held for 1-3 hours.
[0017] In step (2) of the present invention, the preferred oxidation temperature is 285-295℃, more preferably 290℃; the oxidation time is 25-35min, more preferably 30min.
[0018] In step (3) of the present invention, the M-containing compound is preferably palladium chloride or chloroplatinic acid.
[0019] In step (3) of the present invention, the preferred replacement temperature is 60-80 ℃ and the replacement time is 24-48 hours.
[0020] In step (3) of the present invention, it is preferable that the mass ratio of the replacement M to the oxidized WC@Cu particles is 4-6:100, such as 4:100, 5:100, 6:100, or any range between the two mentioned above.
[0021] In a second aspect, the present invention provides a WC@Cu / M composite material prepared according to the preparation method described in the first aspect.
[0022] Thirdly, this invention provides the application of the WC@Cu / M described in the second aspect as an electrocatalyst in the synergistic electro-oxidation of glycerol for hydrogen production. Results show that the WC@Cu / M significantly improves catalytic performance compared to commercial Pt / C.
[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0024] (1) Advantages of the preparation method: This invention first utilizes carbonization self-assembly to form core-shell structured nanoscale WC@Cu, then performs micro-oxidation on the Cu surface, and finally achieves good dispersion of noble metals on the carrier surface through a simple substitution reaction. The degree of micro-oxidation on the Cu surface is controlled by conditions such as reaction temperature, while Pd in the WC@Cu noble metal-loaded composite material is obtained by in-situ substitution of Cu, eliminating many steps and the consumption of raw materials such as reducing agents in conventional reduction methods. The process is simple, and the cost is effectively reduced. The degree of micro-oxidation and the amount of noble metal loaded in the composite material can be easily controlled, and the operation is simple and convenient.
[0025] (2) Advantages of the structural properties of WC@Cu / M composite material: The WC@Cu / M composite material obtained in this invention was micro-oxidized on the Cu surface before Pd replacement of nano-sized WC@Cu, so a certain amount of copper oxide component was introduced into the WC@Cu / M composite material. Experimental results show that this can improve the catalytic activity of WC@Cu / M composite material in glycerol electro-oxidation synergistic hydrogen production.
[0026] (3) Advantages of WC@Cu / M composite material as an electrocatalyst in the electro-oxidation and synergistic hydrogen production of glycerol: WC@Cu / M composite material is used as an electrocatalyst in the electro-oxidation and synergistic hydrogen production of glycerol. Among them, WC@Cu / Pd has a significantly improved performance in glycerol oxidation compared with ordinary commercial Pt / C catalyst and WC@Cu / M composite material without micro-oxidation on Cu surface. Attached Figure Description
[0027] Figure 1a , 1b The images show the SEM morphology of oxidized WC@Cu prepared in Comparative Examples 2 and 1 of this invention. Figure 1c The images show the SEM morphology and elemental scans of the oxidized WC@Cu prepared in Comparative Example 4.
[0028] Figure 2 Characterization diagrams of the catalytic activity of the WC@Cu / Pd composite material prepared in Example 1 of this invention and the commercial Pt / C (5% platinum loading) in Comparative Example 5 for glycerol.
[0029] Figure 3This is a performance comparison chart of the WC@Cu / Pd composite materials prepared in Example 1 and Comparative Examples 1-3 of the present invention.
[0030] Figure 4 This is a performance comparison chart of the WC@Cu / Pd composite materials prepared in Examples 1 and 2 of this invention. Detailed Implementation
[0031] The following embodiments, in conjunction with the accompanying drawings, will further illustrate the present invention, but the scope of protection of the present invention is not limited thereto:
[0032] Example 1
[0033] 1. Preparation of WC@Cu / Pd composite materials
[0034] Nanoparticle precursor powder A of copper hydroxide and ammonium metatungstate was prepared by spray drying. The specific steps were as follows: 20 g of a mixture of ammonium metatungstate (particle size approximately 500 μm) and copper nitrate trihydrate (particle size approximately 500 μm) (tungsten / copper weight ratio 4:1) was added to 20 mL of deionized water. Subsequently, the mixture was spray dried (using a Butch spray dryer B-290) to prepare micron-sized spherical precursors (particle size 1-10 μm). During the spray drying process, the air temperature at the nozzle was 185 °C, and the evaporation rate of the aqueous solution was 15 mL / min.
[0035] Solid powder A was carbonized in a tube furnace under a carbonization atmosphere of a 1:5 mixture of H2 and CO at a total volume ratio of 120 mL / min. The carbonization temperature was increased to 600 °C at a programmed heating rate of 5 °C / min, held for 1 hour, then increased to 900 °C at a programmed heating rate of 3 °C / min, held for 3 hours, and cooled to room temperature to obtain solid B, i.e., nanoscale WC@Cu particle material.
[0036] Solid B was oxidized in an air atmosphere in a muffle furnace at an oxidation temperature of 290 °C for 30 min to cause micro-oxidation of Cu, resulting in solid C, i.e., oxidized WC@Cu particles. Figure 1b Scanning electron microscope (SEM) image of oxidized WC@Cu.
[0037] 40 mg of solid C was added to 3.96 mL of a 5 mM palladium chloride solution for displacement at 60 °C for 48 hours. The palladium chloride solution changed from yellow to colorless and transparent, indicating that Pd had been completely displaced. The solution was then cooled to room temperature, washed three times alternately with deionized water and ethanol, and dried in an oven at 80 °C to obtain the WC@Cu / Pd composite material (Wt). Pd =m Pd ÷m固体C ×100%=5%.
[0038] 2. Performance testing of WC@Cu / Pd composite materials
[0039] The prepared WC@Cu / Pd composite material was used to prepare an electrocatalyst, and the specific steps included:
[0040] (1) Pretreatment of working electrode: First, polish the working electrode (glassy carbon electrode) to a mirror finish with Al2O3 powder and clean it. Then, activate the glassy carbon electrode in 0.2 M / L KCl + 1 mM / L K3Fe(CN)6 solution and perform cyclic voltammetry scan in the potential range of -0.1 to 0.5 V at a scan rate of 50 mV / s. When the peak potential difference of the obtained cyclic voltammetry curve is about 70 mV, the electrode is ready for use.
[0041] (2) Preparation of working electrode: Weigh 5 mg of WC@Cu / Pd composite material and place it in a sample tube. Add 200 μL of deionized water, 190 μL of ethanol and 10 μL of 5% Nafion (purchased from Shanghai Hesen Electric Co., Ltd., model D520) to prepare an emulsion. After ultrasonic dispersion for 30 min, a uniform catalyst slurry is obtained. Use a micropipette to pick up 5 μL of the catalyst slurry and drop it onto the surface of the glassy carbon electrode. Dry it at 50 °C to obtain the working electrode.
[0042] (3) The counter electrode used in the test was a platinum electrode, and the reference electrode was a saturated calomel electrode; the solution used in the cyclic voltammetry test was a mixed aqueous solution of glycerol (0.5 M) and potassium hydroxide (1.0 M), the scan rate was 50 mV / s, and the test temperature was 25 ℃. The results are as follows: Figure 2 and Figure 3 As shown.
[0043] Comparative Example 1:
[0044] 1. Preparation of WC@Cu / Pd composite materials
[0045] Similar to the process in Example 1, the only difference is that solid B is not oxidized, but instead 40 mg of solid B is used to directly replace 40 mg of solid C in palladium chloride solution for metal substitution, resulting in WC@Cu / Pd composite material.
[0046] 2. Performance testing of WC@Cu / Pd composite materials
[0047] The testing process was the same as in Example 1, and the results were as follows: Figure 3 As shown.
[0048] Comparative Example 2:
[0049] 1. Preparation of WC@Cu / Pd composite materials
[0050] The process was similar to that in Example 1, except for the oxidation temperature: 110 °C. The obtained WC@Cu / Pd composite particles were intact with a particle size of 580 nm.
[0051] 2. Performance testing of WC@Cu / Pd composite materials
[0052] The testing process was the same as in Example 1, and the results were as follows: Figure 3 As shown.
[0053] Comparative Example 3:
[0054] 1. Preparation of WC@Cu / Pd composite materials
[0055] The process was similar to that in Example 1, except for the oxidation temperature: 220 °C. The obtained WC@Cu / Pd composite particles were intact with a particle size of 750 nm.
[0056] 2. Performance testing of WC@Cu / Pd composite materials
[0057] The testing process was the same as in Example 1, and the results were as follows: Figure 3 As shown.
[0058] Comparative Example 4:
[0059] 1. Preparation of WC@Cu / Pd composite materials
[0060] The process was similar to that in Example 1, except for the oxidation temperature: 360 °C. The obtained WC@Cu / Pd composite particles were intact with a particle size of 630 nm.
[0061] 2. Performance testing of WC@Cu / Pd composite materials
[0062] The testing process is the same as in Example 1.
[0063] Comparative Example 5
[0064] Commercial Pt / C (5% platinum loading, purchased from Aladdin Reagent (Shanghai) Co., Ltd.) was used as a comparison. Performance tests were conducted using the method described in Example 1, and the results are as follows: Figure 2 As shown.
[0065] Example 2:
[0066] 1. Preparation of WC@Cu / Pd composite materials
[0067] The process was similar to that of Example 1, except for the replacement conditions: solid C was replaced in a 5 mM PdCl2 solution at a temperature of 60°C for 24 hours. The remaining steps were the same as in Example 1.
Claims
1. A method for preparing a WC@Cu / M composite material, characterized in that: M is a noble metal, and the preparation method includes the following steps: (1) Nanoscale WC@Cu particles were obtained, wherein the weight ratio of Cu to W was 1:3-10; the particles had a core-shell structure with WC as the core and Cu as the shell. (2) Place the nano-sized WC@Cu particles in a muffle furnace and oxidize them in air at 280-300℃ for 20-40 min to obtain oxidized WC@Cu particles; (3) The oxidized WC@Cu particles are placed in a solution containing compound M to carry out a displacement reaction, so that the mass ratio of the displacement M to the mass of the oxidized WC@Cu particles is 1-10:
100. Then, solid-liquid separation and drying are performed to obtain WC@Cu / M composite material.
2. The preparation method according to claim 1, characterized in that: M is platinum or palladium.
3. The preparation method according to claim 1 or 2, characterized in that: The weight ratio of Cu to W in the nanoscale WC@Cu particles is 1:3-5.
4. The preparation method according to claim 3, characterized in that: The weight ratio of Cu to W in the nanoscale WC@Cu particles is 1:
4.
5. The preparation method according to claim 1 or 2, characterized in that: In step (2), the oxidation temperature is 285-295℃ and the oxidation time is 25-35 min.
6. The preparation method according to claim 5, characterized in that: In step (2), the oxidation temperature is 290℃ and the oxidation time is 30 min.
7. The preparation method according to claim 2, characterized in that: In step (3), the M-containing compound is palladium chloride or chloroplatinic acid.
8. The preparation method according to claim 1 or 2, characterized in that: In step (3), the mass ratio of the displacement M to the mass of the oxidized WC@Cu particles is 4-6:
100.
9. A WC@Cu / M composite material prepared by the preparation method according to any one of claims 1-8.
10. The application of WC@Cu / M as an electrocatalyst in the synergistic electro-oxidation of glycerol for hydrogen production as described in claim 9.