阅读说明：本技术 一种自支撑Ni掺杂WP2纳米片阵列电催化剂及其制备方法 (Self-supporting Ni-doped WP2Nanosheet array electrocatalyst and preparation method thereof ) 是由 刘勇平 刘威 吕慧丹 耿鹏 庄杨 肖智中 于 2020-05-08 设计创作，主要内容包括：本发明提供了一种自支撑Ni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)将导电基底材料置于有乙醇、草酸、六氯化钨和氯化镍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Ni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,将导电基底材料上的镍掺杂三氧化钨纳米片阵列磷化还原为镍掺杂二磷化钨纳米片阵列,得到Ni掺杂WP<Sub>2</Sub>纳米片阵列电催化析氢电极材料。本发明方法制得到的自支撑Ni掺杂WP<Sub>2</Sub>纳米片阵列电催化析氢电极材料具有较高的电催化析氢活性和稳定性。(The invention provides a self-supporting Ni-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 with a mixed solution of ethanol, oxalic acid, tungsten hexachloride and nickel chloride, carrying out solvothermal reaction for 6-12h at the temperature of 100-220 ℃, and then carrying out a muffle furnaceSintering to obtain Ni-doped WO 3 A 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 nickel-doped tungsten trioxide nanosheet array on a conductive substrate material is phosphorized and reduced into a nickel-doped tungsten diphosphide nanosheet array, so that Ni-doped WP (tungsten phosphide) is obtained 2 The nano-sheet array electrocatalytic hydrogen evolution electrode material. The self-supporting Ni-doped WP prepared by the method 2 The nano-sheet array electro-catalysis hydrogen evolution electrode material has higher electro-catalysis hydrogen evolution activity and stability.)

1. Self-supporting Ni-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 nickel chloride, carrying out solvothermal reaction for 6-12h at the temperature of 100-220 ℃, and sintering in a muffle furnace to obtain Ni-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 nickel-doped tungsten trioxide nanosheet array on a conductive substrate material is phosphorized and reduced into a nickel-doped tungsten diphosphide nanosheet array, so that Ni-doped WP (tungsten phosphide) is obtained₂The nano-sheet array electrocatalytic hydrogen evolution electrode material.

2. Self-supporting Ni-doped WP in accordance with 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 nickel chloride (Ni: W): 0.5-50%.

3. Self-supporting Ni-doped WP in accordance with 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. Self-supporting Ni-doped WP according to any one of claims 1-3₂The preparation method of the nanosheet array electrocatalyst is characterized in that the conductive substrate 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. Self-supporting Ni-doped WP in accordance with 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. Self-supporting Ni-doped WP in accordance with 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. Self-supporting Ni-doped WP in accordance with 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 double-temperature zone tube furnace, and doping the Ni 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 650-750 ℃ at the temperature rise rate of 2-10 ℃/min under the atmospheric pressure, simultaneously heating the upstream central heating zone to 250-350 ℃, and preserving heat for 1-3 h.

8. Self-supporting Ni-doped WP in accordance with claim 7₂Nanosheet array electrocatalyst preparationThe preparation method is characterized in that the operation of introducing argon and removing 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. Self-supporting Ni-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 a self-supporting Ni-doped WP₂Nanosheet array electrocatalyst and to the self-supporting Ni-doped WP₂A preparation method of a nanosheet array electrocatalyst.

Background

Hydrogen is the most promising candidate as a replacement for fossil fuels as a clean, renewable and high heat of combustion value energy source. Among many hydrogen production technologies, electrocatalytic hydrogen production is a simple and efficient method. It is noted that a Pt-based noble metal catalyst is favored in initial studies of an electrocatalytic Hydrogen Evolution Reaction (HER) because of its low initial hydrogen evolution potential and excellent catalytic performance. However, as a noble metal, the scarcity and high price of raw materials limit its application in the field of electrocatalytic hydrogen production.

The tungsten phosphide has low cost and abundant earth resource reserves, and has excellent conductivity, corrosion resistance and high stability, so that the tungsten phosphide becomes the most widely researched high-efficiency HER electrocatalyst material in a pH range. Heteroatom doping is one of the most effective methods for manipulating the chemical and physical properties of materials, and therefore, the use of doping with metal heteroatoms to improve the catalytic activity of materials themselves has been the focus of research. Among inorganic electrocatalysts of various morphologies, materials having a layered structure of two-dimensional nanosheet morphology have received much attention due to their high specific surface area and more exposed active sites that are advantageous for the electrocatalytic hydrogen evolution reaction.

Disclosure of Invention

The first purpose of the invention is to provide a self-supporting Ni-doped WP₂The preparation method of the nanosheet array electrocatalyst solves the problems of the existing WP₂The nano-sheet electro-catalysis hydrogen evolution performance is not excellent enough.

The second purpose of the invention is to provide a self-supporting Ni-doped WP prepared by the method₂A nanosheet array electrocatalyst.

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

self-supporting Ni-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 nickel chloride, carrying out solvothermal reaction for 6-12h at the temperature of 100-220 ℃, and sintering in a muffle furnace to obtain Ni-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 nickel-doped tungsten trioxide nanosheet array on a conductive substrate material is phosphorized and reduced into a nickel-doped tungsten diphosphide nanosheet array, so that Ni-doped WP (tungsten phosphide) is obtained₂The nano-sheet array electrocatalytic hydrogen evolution electrode material.

The method firstly prepares a nickel-doped tungsten trioxide nanosheet array on a conductive substrate material with a self-supporting three-dimensional nanostructure through a solvothermal method, and then prepares self-supporting Ni-doped WP 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 nickel chloride (Ni: W): 0.5-50%.

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 substrate 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 double-temperature zone tube furnace, and doping the Ni 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 650-750 ℃ at the temperature rise rate of 2-10 ℃/min under the atmospheric pressure, simultaneously heating the upstream central heating zone to 250-350 ℃, 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:

self-supporting Ni-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 self-supporting Ni-doped WP₂Preparation method of nanosheet array electrocatalyst for obtaining Ni-doped WP (tungsten doped nitride) on conductive substrate material₂The nano-sheet array electrocatalytic hydrogen evolution electrode material has large specific surface area and more exposed reaction active sitesThe catalyst has high electrocatalytic hydrogen evolution activity and stability; compared with pure WP₂At a current density of 10mAcm^-2The overpotential of the time is reduced from 145mV to 110mV, and the Tafel slope is reduced from 80mV dec^-1Decrease to 67mV dec^-1。

(2) The method is simple, low in cost and easy to control reaction conditions. An effective strategy is provided for preparing a more stable and efficient non-noble metal electrocatalyst by using a doping method so as to improve the performance of HER, which helps promote the potential application of the integrated flexible electrode material in hydrogen production through electrochemical water decomposition.

Drawings

FIG. 1 shows Ni-doped WP obtained from examples 1-5 of the present invention₂An XRD (X-ray diffraction) spectrum of the nano-sheet array electro-catalysis hydrogen evolution electrode material.

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

FIG. 3 shows Ni-doped WP obtained from examples 1-5 of the present invention₂LSV curve diagram of the nano-sheet array electro-catalysis hydrogen evolution electrode material.

FIG. 4 shows Ni-doped WP obtained from examples 1-5 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.