Preparation And Electrocatalytic Hydrogen Evolution Of Cobalt-Based Phosphide Catalyst

As an environmentally friendly resource that could replace traditional fossil fuels,hydrogen is of vital importance to sustainable development and environmental protection.Among various hydrogen production strategies,the environmentally friendly and convenient electrolytic water hydrogen evolution reaction(HER)has attracted much attention.In addition,in order to reduce energy consumption,catalysts are necessary.Among the catalysts used as HER,platinum-based materials have excellent performance.However,there is still an urgent need to design a cheap and easily available high-activity material to replace the scarce platinum-based material to reduce costs.The performance of cobalt-based catalyst could be close to that of platinum-based catalyst by modification of cobalt-based material.On the one hand,the morphology and active sites of the catalysts could be improved by introducing a metal-organic framework.On the other hand,the inherent catalytic activity of the materials could be improved by incorporating other transition metals(e.g.,Mo and W)into the cobalt-based catalysts.Based on the above ideas,two different methods were used to prepare cobalt-based catalysts.The research contents of this paper are as follows:1.The cobalt-based material with nanowire structure is grown on the surface of nickel foam by hydrothermal method,then introducing Prussian blue analogues into it to obtain the precursor,and the morphology of the precursor is adjusted by alkali etching.After phosphating the precursor,a highly active bimetallic phosphide catalyst(Co-Fe-P/NF)that only needs an overpotential of 112 m V to achieve a current density of 100 m A/cm~2 could be obtained on the surface of the nickel foam,In addition,the Tafel slope and load transfer impedance are 50.7 m V/dec and 1.893Ω,respectively.Introduction of Prussian blue analogues and alkaline etching could effectively increase the electrochemical surface area and the electrical conductivity,and enhance the catalytic activity of the material.2.The cobalt-based material with microplate structure is grown on the surface of nickel foam by hydrothermal method,and then Mo was mixed into it to obtain the precursor with the nanosheet structure.And bimetallic phosphide(Mo-CoP)with nanosheet structure was obtained after phosphating only needs an overpotential of 112 m V to achieve a current density of 100 m A/cm~2.In addition,the Tafel slope and load transfer impedance are 69.1m V/dec and 0.5927Ω,respectively.This excellent catalytic performance could be attributed to the fully exposed active sites and the stronger intrinsic activity obtained after Mo doping.