Preparation And Electrocatalytic Performance Of Molybdenum Disulfide Based Hybrid Electrode For Electrochemical Overall Water Splitting

The problems of energy shortage and environmental pollution become increasingly severe with the gradual consumption of fossil fuels.Therefore,it is particularly urgent to develop efficient,cost-effective and sustainable green energy.Hydrogen has been recognized as one of the most promising green energy source due to the advantages of high energy conversion efficiency,clean and renewable.Electrocatalytic water splitting is one of the most effective ways of hydrogen production.At present,Pt-based metal and Ru,Ir-based metal oxide still are the state-of-the-art electrocatalysts to drive HER and OER,respectively.However,the large-scale commercial applications of noble metal materials are severely restricted by their scarce reserves,high cost and poor stability.As a result,most researchers focus on searching and preparing non-precious metal catalyst materials with characteristics of low-cost,high-efficiency and contamination free.Molybdenum disulfide?MoS₂?has been widely studied due to its large reserves,good catalytic performance and environment-friendly.However,its catalytic performance for hydrogen evolution and oxygen evolution under alkaline conditions remains to be improved.Therefore,in this paper,a series of MoS₂ based electrocatalysts are constructed from the doping of heteroatom and the coupling interface and the performance of electrocatalytic overwall water splitting has been systematically studied.The main research contents and experimental results are as follows:1.Tungsten doped MoS₂@Ni₃S₂(Mo_?1-x?W_xS₂@Ni₃S₂)hybrid electrode was prepared on 3D nickel foam substrate by a facile one-step hydrothermal method,and its electrocatalytic properties of HER and OER were systematically investigated.The results show that only 98 and 285 mV for HER and OER overpotentials were needed to acquire the current density of 10 mA cm^-22 for the Mo_?1-x?W_xS₂@Ni₃S₂ hybrid electrode,and its overall water splitting voltage was merely 1.62 V.The excellent electrocatalytic properties of the electrode can be attributed to the W doping effectively regulates the electronic structure of MoS₂.Therefore,the successful preparation of Mo_?1-x?W_xS₂@Ni₃S₂ hybrid electrode provides a new research idea for the design of high efficient and stable overall water splitting bifunctional catalysts.2.The NiOOH modified MoS₂@Ni₃S₂?MoS₂@Ni₃S₂ NWs-NF/NiOOH?hybrid electrode was prepared by the combination of hydrothermal and solvothermal method,and it was applied to the field of electrocatalytic water splitting.The experimental results show that the combination of NiOOH and MoS₂@Ni₃S₂ is conductive to the improvement of the conductivity of the electrode materials.The synergistic effects originated from the coupled interfaces of the catalysts obviously improves the catalytic activity of the electrode.Only 101 and 266 mV are needed to drive the current density of 10 mA cm^-22 for HER and OER of MoS₂@Ni₃S₂ NWs-NF/NiOOH electrode,respectively,and the overall water splitting voltage is 1.60 V.This experiment provides a new direction for the design and preparation of high-performance bifunctional electrocatalysts.3.The FeOOH modified MoS₂@Ni₃S₂?MoS₂@Ni₃S₂ NWs-NF/FeOOH?hybrid electrode was synthesized by the combination of hydrothermal method and the galvanostatic electrodeposition,and the electrocatalytic properties of the electrode were studied systematically.The experimental results show that when the current density is 10 mA cm^-2,the HER and OER overpotentials of the MoS₂@Ni₃S₂NWs-NF/Fe OOH electrode are 95 and 234 mV,respectively,and the overall water splitting voltage is only 1.57 V.In addition,density functional theory?DFT?calculation indicates that the existence of the coupling interface effectively optimizes the chemisorption energy of H and oxygen intermediates,hence promotes the HER and OER processes.Therefore,this work marks an important step in developing cost-effective catalytic decomposition materials.