Preparation And Performance Study Of Cobalt-based Catalyst

Electrocatalytic water decomposition reactions are generally divided into two half reactions:Hydrogen Evolution Reaction(HER)at the cathode and Oxygen Evolution Reaction(OER)at the anode.Among them,HER is a reaction,which involving double electron transfer and simple reaction path.Compared with HER,OER is a four-electron reaction with a complex reaction path and high over-potential,which is the key to electrocatalytic water decomposition.Therefore,electrocatalyst with excellent catalytic activity and high stability can fully reduce voltage of water decomposition,which can save energy.Hence,to study OER catalysts is benefit for development of clean energy.According to current research reports that noble metal catalysts are still commercially available OER catalysts,but high cost of these catalysts is not conducive to the development of electrocatalytic water decomposition technology.So,researchers hope to develop non-noble metal based catalysts.As a very cheap metal,Fe is expected to be used by doping,which not only reduces the amount of other metals but also improves the catalytic activity by adjusting the electronic structure.The main contents are as follows:1.Sulfur compounds are synthesized by two-step hydrothermal method,which has the problems of long preparation time and high energy consumption.In this chapter,a simple microwave-assisted heating method is used to synthesize iron-cobalt sulfide,which can effectively reduce the cost.In addition,carbon materials such as carbon nanotubes and graphene are mostly used to improve the conductivity of sulfide.However,the cost of these carbon materials is too high.We used cheap,abundant pore structure and oxygen-containing group XC-72 as the carrier of FeCoS2.The results show that when XC-72 is used as the carrier of FeCoS2,the crystallinity and charge transfer resistance of FeCoS2 are reduced,and the OER activity of FeCoS2 is enhanced.2.Three carbon materials of XC-72,CNT and GO are used as carbon carriers in this chapter,since electrocatalytic water decomposition is a three-phase interface reaction.3D carbon material loaded FeCoP(FeCoP/C)is constructed via a physical method.The results show that FeCoP/C presents a petal-like morphology,which not only increases infiltration between surface area and electrodes,but also provids a channel for oxygen escaping,making FeCoP/C becoming a good bifunctional catalyst for electrolysis of water.3.Electrode materials loaded on nickel foam substrate by hydrothermal method is the research hotspot of macroscopic self-supporting electrode.In this chapter,electrocatalytic activities of nickel foam,iron foam and nickel-iron foam substrates are compared.The electrochemical results show that the electrocatalytic activity of nickel-iron foam is best,which may be caused by synergistic effect of nickel and iron metals.Then NiFeP catalyst is prepared via directly phosphating nickel-iron foam.The electrocatalytic properties of NiFeP catalyst are discussed in this chapter.