阅读说明：本技术 一种三维Co掺杂WP2纳米片阵列电催化剂及其制备方法 (Three-dimensional Co-doped WP2Nanosheet array electrocatalyst and preparation method thereof ) 是由 刘勇平 刘威 吕慧丹 耿鹏 李时庆 王子良 于 2020-05-08 设计创作，主要内容包括：本发明提供了一种三维Co掺杂WP<Sub>2</Sub>纳米片阵列电催化剂制备方法,包括以下步骤：(1)将导电基质材料置于有乙醇、草酸、六氯化钨和氯化钴混合溶液的聚四氟乙烯反应釜中,在100-220℃的条件下进行溶剂热反应6-12h,再在马弗炉中烧结得到Co掺杂WO<Sub>3</Sub>纳米片阵列；(2)以次亚磷酸钠为磷源,在双温控真空气氛管式炉中使用原位磷化还原的方法,在氩气环境下,将导电基质材料上的钴掺杂三氧化钨纳米片阵列磷化还原为钴掺杂二磷化钨纳米片阵列,得到Co掺杂WP<Sub>2</Sub>纳米片阵列电催化析氢电极材料。本发明方法制得的三维Co掺杂WP<Sub>2</Sub>纳米片阵列电极材料具有较大暴露的比表面积,较高的电催化析氢活性和稳定性。(The invention provides three-dimensional Co-doped WP 2 The preparation method of the nanosheet array electrocatalyst comprises the following steps of: (1) placing the conductive substrate material in a polytetrafluoroethylene reaction kettle containing a mixed solution of ethanol, oxalic acid, tungsten hexachloride and cobalt chloride, carrying out solvothermal reaction for 6-12h at the temperature of 100-220 ℃, and sintering in a muffle furnace to obtain Co-doped WO 3 A nanosheet array; (2) sodium hypophosphite is used as a phosphorus source, and vacuum gas is subjected to double temperature controlIn-situ phosphorization reduction method is used in an atmosphere tube furnace, under argon environment, cobalt-doped tungsten trioxide nanosheet array on conductive substrate material is phosphorized and reduced into cobalt-doped tungsten diphosphide nanosheet array, and Co-doped WP is obtained 2 The nano-sheet array electrocatalytic hydrogen evolution electrode material. Three-dimensional Co-doped WP prepared by the method 2 The nano-sheet array electrode material has larger exposed specific surface area, higher electrocatalytic hydrogen evolution activity and stability.)

1. Three-dimensional Co-doped WP₂The preparation method of the nanosheet array electrocatalyst is characterized by comprising the following steps of:

(1) placing the conductive substrate material in a polytetrafluoroethylene reaction kettle containing a mixed solution of ethanol, oxalic acid, tungsten hexachloride and cobalt chloride, carrying out solvothermal reaction for 6-12h at the temperature of 100-220 ℃, and sintering in a muffle furnace to obtain Co-doped WO₃A nanosheet array;

(2) in the method, sodium hypophosphite is used as a phosphorus source, and an in-situ phosphorization reduction method is used in a double-temperature-control vacuum atmosphere tube furnace, under the argon environment, a cobalt-doped tungsten trioxide nanosheet array on a conductive substrate material is phosphorized and reduced into a cobalt-doped tungsten diphosphide nanosheet array, so that Co-doped WP (tungsten phosphide) is obtained₂The nano-sheet array electrocatalytic hydrogen evolution electrode material.

2. The three-dimensional Co-doped WP of claim 1₂The preparation method of the nanosheet array electrocatalyst is characterized in that the volume of ethanol in the mixed solution is as follows: 10-60mL, and the mass of oxalic acid is: 0.1-1g, mass of tungsten hexachloride: 0.1-0.5g, mole percent of cobalt chloride (Co: W): 0.5 to 20 percent.

3. The three-dimensional Co-doped WP of claim 1₂The preparation method of the nanosheet array electrocatalyst is characterized in that in the step (1), the muffle furnace sintering temperature rise rate is 1-5 ℃/min, the temperature rises to 400-600 ℃ and the sintering lasts for 1-5 h.

4. Three-dimensional Co-doped WP according to any one of claims 1 to 3₂The preparation method of the nanosheet array electrocatalyst is characterized in that the conductive matrix material in the step (1) is subjected to hydrophilic treatment by using nitric acid before being subjected to solvothermal reaction, and then is subjected to ultrasonic cleaning in acetone, deionized water and ethanol respectively.

5. The three-dimensional Co-doped WP of claim 1₂The preparation method of the nanosheet array electrocatalyst is characterized in that the conductive substrate material is carbon cloth, carbon paper, FTO, carbon nanotubes and TiO₂A nanotube.

6. The three-dimensional Co-doped WP of claim 1₂The preparation method of the nanosheet array electrocatalyst is characterized in that the mass of the sodium hypophosphite in the step (2) is 1-5 g.

7. The three-dimensional Co-doped WP of claim 1₂The preparation method of the nanosheet array electrocatalyst is characterized in that in the step (2), in-situ phosphorization reduction is carried out in a double-temperature-control vacuum atmosphere tube furnace, and the specific operation is as follows: placing sodium hypophosphite in a quartz boat in a central heating zone at the upstream of the two-temperature zone tube furnace, and doping the Co obtained in the step (1) with WO₃The nano-sheet array is arranged on another quartz boat which is positioned in a central heating zone at the downstream of the double-temperature zone tube furnace; introducing argon to remove air, heating the downstream central heating zone to 800 ℃ at the temperature rise rate of 2-10 ℃/min under the atmospheric pressure, simultaneously heating the upstream central heating zone to 350 ℃ at the temperature of 250 ℃ and preserving heat for 1-3 h.

8. The three-dimensional Co-doped WP of claim 7₂The preparation method of the nanosheet array electrocatalyst is characterized in that the operation of introducing argon to remove air is as follows: before the heating process, introducing argon for 20 min; and in the temperature rise process, the argon flow of the gas path system is set to be 100s.c.c.m, and in the heat preservation stage, the argon flow is switched to be 20 s.c.c.m.

9. Three-dimensional Co-doped WP₂Nanosheet array electrocatalyst characterized by being prepared by the method of any one of claims 1 to 8.

Technical Field

The invention belongs to the technical field of electrocatalysis and hydrogen evolution electrode materials, and particularly relates to three-dimensional Co-doped WP (WP)₂Nanosheet array electrocatalyst and to the three-dimensional Co-doped WP₂A preparation method of a nanosheet array electrocatalyst.

Background

With the development of society, people face the problems of continuous consumption of fossil energy (petroleum, coal, natural gas and the like) and increasingly serious environmental pollution, so that the development of renewable energy (solar energy, hydrogen energy, hydroenergy, tidal energy, wind energy, biomass energy and the like) arouses great interest, and the advantages of zero hydrogen energy carbon footprint, high energy density and the like are widely concerned and researched. The hydrogen production process by electrolyzing water in a plurality of hydrogen production technologies is simple, environment-friendly and pollution-free, and accords with the strategy of sustainable development, so the method has great application prospect.

The most studied non-noble metal electrocatalysts in recent years have mainly focused on transition metal compounds (Fe, Co, Ni, W, Mo, etc.), among which Transition Metal Phosphides (TMPs) have been extensively studied for their high mechanical strength, electrical conductivity and stability. In addition, most hydrogen evolution electrocatalysts are powders, require high molecular polymer binders, Nafion or PTFE, to be effectively immobilized on the electrode, which may increase the series resistance or reduce the active sites, hindering electron diffusion, and thus inhibiting the activity of the catalyst. In view of this, there is a need to provide a hydrogen evolution active electrode material with high electrocatalytic activity.

Disclosure of Invention

The invention aims to provide three-dimensional Co-doped WP₂Nanosheet array electrocatalystThe preparation method solves the problems of few reaction active sites and low catalytic activity of the existing electrocatalyst.

The second purpose of the invention is to provide three-dimensional Co-doped WP prepared by the method₂A nanosheet array electrocatalyst.

The first purpose of the invention is realized by the following technical scheme:

three-dimensional Co-doped WP₂The preparation method of the nanosheet array electrocatalyst comprises the following steps of:

(1) placing the conductive substrate material in a polytetrafluoroethylene reaction kettle containing a mixed solution of ethanol, oxalic acid, tungsten hexachloride and cobalt chloride, carrying out solvothermal reaction for 6-12h at the temperature of 100-220 ℃, and sintering in a muffle furnace to obtain Co-doped WO₃A nanosheet array;

(2) in the method, sodium hypophosphite is used as a phosphorus source, and an in-situ phosphorization reduction method is used in a double-temperature-control vacuum atmosphere tube furnace, under the argon environment, a cobalt-doped tungsten trioxide nanosheet array on a conductive substrate material is phosphorized and reduced into a cobalt-doped tungsten diphosphide nanosheet array, so that Co-doped WP (tungsten phosphide) is obtained₂The nano-sheet array electrocatalytic hydrogen evolution electrode material.

The method firstly prepares a cobalt-doped tungsten trioxide nanosheet array with a three-dimensional structure on a conductive substrate material with a self-supporting three-dimensional nanostructure through a solvothermal method, and then prepares three-dimensional Co-doped WP (tungsten trioxide) which grows on the conductive substrate material in an interlaced manner through an in-situ phosphorization reduction method₂A nanosheet array material. The self-supporting three-dimensional nanostructures on the conductive substrate not only provide a large electrochemically active surface area, but also accelerate electron transport and enhance gas evolution.

The preparation method of the invention can be further improved as follows:

volume of ethanol in the mixed solution: 10-60mL, and the mass of oxalic acid is: 0.1-1g, mass of tungsten hexachloride: 0.1-0.5g, mole percent of cobalt chloride (Co: W): 0.5 to 20 percent.

In the step (1), the muffle furnace sintering heating rate is 1-5 ℃/min, the temperature is raised to 400-600 ℃, and sintering is carried out for 1-5 h.

Performing hydrophilic treatment on the conductive matrix material by using nitric acid before performing solvothermal reaction in the step (1), and then performing ultrasonic cleaning in acetone, deionized water and ethanol respectively.

Further, each ultrasonic cleaning time was 20 min.

The conductive substrate material is carbon cloth, carbon paper, FTO, carbon nanotube, TiO₂A nanotube.

The mass of the sodium hypophosphite in the step (2) is 1-5 g.

The argon in the step (2) is argon with the purity of 99.99 percent.

In the step (2), in-situ phosphorization reduction is carried out in a double-temperature-control vacuum atmosphere tube furnace, and the specific operation is as follows: placing sodium hypophosphite in a quartz boat in a central heating zone at the upstream of the two-temperature zone tube furnace, and doping the Co obtained in the step (1) with WO₃The nano-sheet array is arranged on another quartz boat which is positioned in a central heating zone at the downstream of the double-temperature zone tube furnace; introducing argon to remove air, heating the downstream central heating zone to 800 ℃ at the temperature rise rate of 2-10 ℃/min under the atmospheric pressure, simultaneously heating the upstream central heating zone to 350 ℃ at the temperature of 250 ℃ and preserving heat for 1-3 h.

Further, the operation of introducing argon to remove air is as follows: before the heating process, introducing argon for 20 min; and in the temperature rise process, the argon flow of the gas path system is set to be 100s.c.c.m, and in the heat preservation stage, the argon flow is switched to be 20 s.c.c.m.

The second purpose of the invention is realized by the following technical scheme:

three-dimensional Co-doped WP₂The nanosheet array electrocatalyst is prepared by the above method.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention relates to three-dimensional Co-doped WP₂Preparation method of nanosheet array electrocatalyst for preparing three-dimensional Co-doped WP on conductive substrate material₂The nano-sheet array electrode material has larger exposed specific surface area, higher electrocatalytic hydrogen evolution activity and stability; when the doping concentration is 1 percent, the electrolyte has the optimum different electrocatalytic hydrogen evolution performance in 0.5mol/L H2SO4 electrolyteThe current density was 10mA cm^-2The overpotential is 122mV, and the corresponding Tafel slope is 75mV dec^-1。

(2) The method is simple, low in cost and easy to control reaction conditions. Provides an effective method for preparing a high-activity three-dimensional electrocatalytic hydrogen evolution electrode material by using a transition metal heteroatom doping method on a conductive matrix material, which is beneficial to the progress and development of an electrocatalytic water decomposition technology.

Drawings

FIG. 1 shows the Co-doped WP obtained from examples 1-4 of the present invention₂An XRD (X-ray diffraction) spectrum of the nano-sheet array electro-catalysis hydrogen evolution electrode material.

FIG. 2 shows the Co-doped WP obtained in example 1 of the present invention₂SEM image of the nano-sheet array electro-catalysis hydrogen evolution electrode material.

FIG. 3 shows the Co-doped WP obtained from examples 1-4 of the present invention₂LSV curve diagram of the nano-sheet array electro-catalysis hydrogen evolution electrode material.

FIG. 4 shows the Co-doped WP obtained from examples 1-4 of the present invention₂Tafel curve diagram of nano-sheet array electro-catalysis hydrogen evolution electrode material.

Detailed Description

The present invention is further described below in conjunction with specific examples to better understand and implement the technical solutions of the present invention for those skilled in the art.