Preparation Of The First Transition Metal Catalyst And Its Electrocatalytic Water Oxidation Performance

Recently,with the fast depletion of fossil fuels and increasing environment pollution,it is urgent to explore a clean,cheap and renewable energy.Hydrogen,as the most ideal clean energy so far,gradually attracts the attention of researchers,and the process of electrocatalytic water splitting is an important way which converts electric energy into hydrogen energy.However,due to sluggish kinetics,oxygen evolution reaction?OER?is bottleneck of the whole process of water splitting.Therefore,it is importance to design an effective electrocatalyst to accelerate the reaction and improve the energy conversion efficiency.This thesis describes the design of effective,inexpensive and durable electrocatalysts for oxygen evolution reaction?OER?.The main results obtained are as follows:1.Design a NiFe-based electrode for water oxidation by electrocatalytic modification of Ni foamThe NiFe-based electrode was synthesized by fast,simple and efficient cyclic voltammetry?CV?scans of Ni foam?NF?in an aqueous acetate buffer solution containing FeSO4 from 0 to 1.3 V vs Ag/AgCl.In the process of CV scans,Fe? was gradually oxidized into Fe? and thus deposited uniformly on the surface of the NF and the surface Ni0 metal was oxidized into Ni? simultaneously,which ensured the close contact between the support and the catalyst for improving charge-transfer efficiency.In addition,the good electrical conductivity and large pores of NF make for fast electron transfer and release of gas.Experimental results demonstrated that the NiFe-based electrode exhibited high catalytic performance and outstanding durability under harsh OER conditions.The onset overpotential was only about 240 mV.While overpotential required to reach 100 mA cm^-2 was 290 mV.2.CoO nanoparticles for electrocatalytic water oxidationThis work focused on CoO nanoparticles for water oxidation performance in alkaline condition.We developed a facile and fast protocol to fabricate ?-Co?OH?₂ as precursor by using sodium oleate as the surfactant.A well-dispersed CoO nanoparticles was obtained through the pyrolysis of as-obtained ?-Co?OH?₂ at 200?.Then,CoO nanoparticles were used to study the catalytic activity for water oxidation.Compared with traditional method,this synthetic protocol showed many superiorities such as facile operation and mild condition.It provided a general method for synthesis other kinds of transition metal oxides nanoparticles.Electrochemical method test showed that the electrocatalytic active surface area of CoO sample was significantly improved compared to ?-Co?OH?₂.Experimental results showed that the Tafel slope of CoO nanoparticles was 75 mV dec-1.The overpotential was required to reach 10 mA cm^-2 was 312 mV under alkaline solutions.