阅读说明：本技术 一种镍掺杂硒化钴电催化析氢催化剂及其制备方法 (Nickel-doped cobalt selenide electro-catalysis hydrogen evolution catalyst and preparation method thereof ) 是由 姜再兴 方晓娇 郑文慧 李阳阳 于 2019-10-18 设计创作，主要内容包括：一种镍掺杂硒化钴电催化析氢催化剂及其制备方法,它涉及电催化析氢催化剂及其制备方法。它是要解决现有的掺杂硒化钴电催化析氢催化剂的制备步骤复杂、成本高、安全性差的技术问题。本催化剂的化学通式为Co<Sub>x</Sub>Ni<Sub>y</Sub>Se<Sub>2</Sub>,x＝0.6～0.8,y＝0.1～0.35。制法：将硒粉溶于氢氧化钾溶液中,然加入Co(NO<Sub>3</Sub>)<Sub>2</Sub>·6H<Sub>2</Sub>O、Ni(NO<Sub>3</Sub>)<Sub>2</Sub>·6H<Sub>2</Sub>O、EDTA-2Na和超纯水,搅拌均匀后,得到混合液；然后转移至反应釜中水热反应,再经清洗、干燥,得到催化剂；该催化剂的过电位达到170～195mV VS RHE,连续循环伏安测试1000圈后,极化曲线与初始曲线几乎重合,稳定性高,可用于电催化析氢反应中。(A nickel-doped cobalt selenide electro-catalysis hydrogen evolution catalyst and a preparation method thereof relate to an electro-catalysis hydrogen evolution catalyst and a preparation method thereof. The preparation method aims to solve the technical problems of complex preparation steps, high cost and poor safety of the existing cobalt selenide-doped electrocatalytic hydrogen evolution catalyst. The catalyst has the chemical general formula of Co x Ni y Se 2 X is 0.6 to 0.8, and y is 0.1 to 0.35. The preparation method comprises the following steps: dissolving selenium powder in potassium hydroxide solution, and adding Co (NO) 3 ) 2 ·6H 2 O、Ni(NO 3 ) 2 ·6H 2 O, EDTA-2Na and ultrapure water are evenly stirred to obtain mixed liquid; then transferring the mixture to a reaction kettle for hydrothermal reaction, and then cleaning and drying the mixtureDrying to obtain a catalyst; the overpotential of the catalyst reaches 170-195 mV VS RHE, and after 1000 circles of continuous cyclic voltammetry test, the polarization curve almost coincides with the initial curve, so that the catalyst has high stability and can be used in an electrocatalytic hydrogen evolution reaction.)

1. A nickel-doped cobalt selenide electro-catalysis hydrogen evolution catalyst is characterized in that the chemical general formula of the catalyst is Co_xNi_ySe₂Wherein x is 0.6-0.8, and y is 0.1-0.35.

2. The method for preparing the nickel-doped cobalt selenide electro-catalytic hydrogen evolution catalyst as claimed in claim 1, which is characterized by comprising the following steps:

one, press Co_xNi_ySe₂Weighing selenium powder and Co (NO) according to the stoichiometric ratio₃)₂·6H₂O and Ni (NO)₃)₂·6H₂O，Co_xNi_ySe₂Wherein x is 0.6-0.8, and y is 0.1-0.35; then weighing potassium hydroxide solution, EDTA-2Na and ultrapure water;

secondly, dissolving the selenium powder in a potassium hydroxide solution, stirring for 25-35 min, and adding Co (NO)₃)₂·6H₂O、Ni(NO₃)₂·6H₂O, EDTA-2Na and ultrapure water, and continuously stirring for about 1-1.5 h to obtain a mixed solution;

thirdly, transferring the mixture into a Teflon reaction kettle, reacting for 10-16 h at the temperature of 160-200 ℃, and naturally cooling to room temperature;

and fourthly, washing the black precipitate obtained by the reaction with water and ethanol in sequence, and then placing the black precipitate in a vacuum oven at the temperature of 60-65 ℃ for 12-15 hours to obtain the nickel-doped cobalt selenide electro-catalysis hydrogen evolution catalyst.

3. The preparation method of the nickel-doped cobalt selenide electro-catalytic hydrogen evolution catalyst as claimed in claim 2, wherein the concentration of the potassium hydroxide solution in the step one is 20-25 mol/L.

4. The method for preparing a nickel-doped cobalt selenide electro-catalytic hydrogen evolution catalyst according to claim 2 or 3, wherein the molar ratio of the selenium powder to the potassium hydroxide in the potassium hydroxide solution in the step one is 1: (50-60).

5. The method for preparing the nickel-doped cobalt selenide electro-catalytic hydrogen evolution catalyst according to claim 2 or 3, wherein the molar ratio of the selenium powder to the EDTA-2Na in the step one is 1: (0.8-0.9).

6. The method for preparing a nickel-doped cobalt selenide electro-catalytic hydrogen evolution catalyst as claimed in claim 2 or 3, wherein in the first step, the ratio of the amount of the selenium powder to the volume of the ultrapure water is 1 mmol: (10-12) mL.

Technical Field

The invention relates to an electrocatalytic hydrogen evolution catalyst and a preparation method thereof.

Background

With the development of global economy, fossil fuels are gradually exhausted, and meanwhile, environmental problems such as air pollution and the like caused by the combustion of the fossil fuels force people to find clean and renewable new energy sources such as solar energy, wind energy, biological energy, hydrogen energy and the like. Among these new energy sources, hydrogen is widely concerned by people because its source is wide, the combustion product is pollution-free water, and the energy generated by hydrogen per unit mass is larger than other energy sources and the energy utilization rate is high. However, the hydrogen is generated by electrolyzing water, the dynamic process is slow, and high overpotential is often needed, so that a hydrogen evolution reaction catalyst is needed to reduce high energy consumption needed in the electrolysis process, and the water electrolysis reaction is realized efficiently. At present, platinum group metals are the best electrochemical hydrogen evolution catalysts, but the rarity and high cost of the platinum group metals also make the electrochemical hydrogen evolution catalysts difficult to popularize and use on a large scale. Among other non-noble metal catalysts, cobalt-based compounds including cobalt disulfide, cobalt selenide, cobalt carbide, and the like have attracted considerable attention in the past few years, but have poor catalytic performance. In order to further improve the electrocatalytic properties of cobalt-based compounds, they are doped and modified.

The chinese patent with application number 201810123010.2 discloses a preparation method and application of an iron-doped cobalt diselenide composite nitrogen-doped carbon material. The method comprises the steps of taking a metal organic framework ZIF-67 as a precursor, etching by utilizing ferric ions to obtain Fe-ZIF-67 modified by iron, carbonizing and selenizing the Fe-ZIF-67 by utilizing selenium steam at high temperature to obtain iron-doped cobalt diselenide (Fe-CoSe) loaded by nitrogen-doped porous carbon₂@ NC) powdered electrode material. Mixing Fe-CoSe₂The @ NC powder is made into slurry and brushed on the conductive carbon fiber paper to prepare Fe-CoSe₂@ NC/CFP electrode. Fe-CoSe₂The electrochemical catalysis hydrogen production performance indexes of the @ NC/CFP electrode are as follows: the Tafel slope is 40.9 mV/decade; up to 10mA/cm²The overpotential for the current density was-0.143V (vs RHE). The steps involved in this patent are more complex and require chemical etching and high temperature carbonization processes. Chinese patent with application number of 201910171517.XA preparation method of a nitrogen and nickel codoped cobalt selenide ultrathin nanosheet discloses a preparation method of a cobalt selenide doped material, which comprises the steps of mixing a cobalt source, a selenium source, a nickel source, a nitrogen source, water and diethylenetriamine, and carrying out a solvothermal reaction to obtain a nitrogen and nickel codoped cobalt selenide precursor; and then washing and drying the precursor to obtain the nitrogen and nickel co-doped cobalt selenide ultrathin nanosheet. The patent is simultaneously applied to the modification of cobalt selenide by metal doping and nonmetal doping, and has higher preparation cost and poor safety.

Disclosure of Invention

The invention provides a nickel-doped cobalt selenide electro-catalysis hydrogen evolution catalyst and a preparation method thereof, aiming at solving the technical problems of complex preparation steps, high cost and poor safety of the existing cobalt selenide-doped electro-catalysis hydrogen evolution catalyst.

The nickel-doped cobalt selenide electro-catalytic hydrogen evolution catalyst has a chemical general formula of Co_xNi_ySe₂，x＝0.6～0.8，y＝0.1～0.35。

The preparation method of the nickel-doped cobalt selenide electro-catalytic hydrogen evolution catalyst comprises the following steps:

one, press Co_xNi_ySe₂Weighing selenium powder and Co (NO) according to the stoichiometric ratio₃)₂·6H₂O and Ni (NO)₃)₂·6H₂O，Co_xNi_ySe₂Wherein x is 0.6-0.8, and y is 0.1-0.35; then weighing potassium hydroxide solution, EDTA-2Na and ultrapure water;

secondly, dissolving the selenium powder in a potassium hydroxide solution, stirring for 25-35 min, and adding Co (NO)₃)₂·6H₂O、Ni(NO₃)₂·6H₂O, EDTA-2Na and ultrapure water, and continuously stirring for about 1-1.5 h to obtain a mixed solution;

thirdly, transferring the mixture into a Teflon reaction kettle, reacting for 10-16 h at the temperature of 160-200 ℃, and naturally cooling to room temperature;

and fourthly, washing the black precipitate obtained by the reaction with water and ethanol in sequence, and then placing the black precipitate in a vacuum oven at the temperature of 60-65 ℃ for 12-15 hours to obtain the nickel-doped cobalt selenide electro-catalysis hydrogen evolution catalyst.

The overpotential (the current density is 10mA cm) of the nickel-doped cobalt selenide electro-catalytic hydrogen evolution catalyst^-2The time potential) reaches 170-195 mV VS RHE, the Tafel slope reaches 32-62V VS RHE, is very close to platinum, can be compared favorably with the currently accepted best platinum catalyst, and simultaneously has ultrahigh stability, after 1000 circles of continuous cyclic voltammetry test, the polarization curve is almost overlapped with the initial curve, 10000s under the overpotential condition, the current density is not obviously changed, and the stability in the acid electrolyte is good.

The nickel-doped cobalt selenide electro-catalysis hydrogen evolution catalyst has simple and complex preparation steps, low cost and safety. Can be used in electrocatalytic hydrogen evolution reaction.

Drawings

FIG. 1 shows materials CNSe-1, CNSe-2, CNSe-3, CNSe-4 and CoSe prepared in examples 1 to 4 and comparative examples 1 to 2₂And NiSe₂A polarization graph of (a);

FIG. 2 shows materials CNSe-1, CNSe-2, CNSe-3, CNSe-4 and CoSe prepared in examples 1 to 4 and comparative examples 1 to 2₂And NiSe₂A tafel slope plot of (a);

FIG. 3 shows materials CNSe-1, CNSe-2, CNSe-3, CNSe-4 and CoSe prepared in examples 1 to 4 and comparative examples 1 to 2₂And NiSe₂The overpotential histogram of (a);

FIG. 4 shows materials CNSe-1, CNSe-2, CNSe-3, CNSe-4 and CoSe prepared in examples 1 to 4 and comparative examples 1 to 2₂And NiSe₂A tafel slope histogram of (a);

FIG. 5 is a chemical formula of Co prepared in example 3_0.77Ni_0.25Se₂The polarization curve of the catalyst CNSe-3 is compared with the polarization curve after 1,000 times of continuous cyclic voltammetry;

FIG. 6 is a chemical formula of Co prepared in example 3_0.77Ni_0.25Se₂The catalyst CNSe-3 of (a) has a 10,000s current density change curve graph at a potential of-179 mV;

FIG. 7 is a chemical formula of Co prepared in example 3_0.77Ni_0.25Se₂Scanning electron micrograph of catalyst CNSe-3 (b);

FIG. 8 is a chemical formula of Co prepared in example 3_0.77Ni_0.25Se₂A transmission electron micrograph of the catalyst CNSe-3 (B).

Detailed Description