Preparation And Performance Study Of Non-noble Metal Self-supporting Electrode For Electrocatalytic Water Oxidation

Traditional fossil energy（coal,oil,natural gas）is a non-renewable energy because of its limited reserves,and its excessive use has brought serious pollution and greenhouse effect to the environment.It has resulted that people wanted to explore more renewable clean energy to replace fossil energy.As a kind of clean energy,hydrogen has received widespread attention.It was shown that electrocatalytic water splitting technology was an ideal hydrogen production method because of its simple process and high purity of hydrogen produced in many studies.In a water splitting reaction,oxygen evolution reaction includes the transfer of four electrons,which is a key step in water splitting.At present,the water oxidation electrode materials put into practical use are some precious metal catalysts（oxides of ruthenium,platinum,iridium,etc.）.However,precious metals cannot be used in large-scale industrial applications due to their high prices and low reserves.Therefore,it is the main research trend to develop non-noble metal electrode materials with high catalytic activity.The powder is stuck to the traditional electrodes by some polymer binders,while self-supporting electrodes can be used directly as electrodes by direct in-situ growth on the conductive substrate,avoiding the addition of binders.Simplifying the preparation process and reducing the cost of electrode,self-supporting electrodes will be the development trend of future electrodes.Based on the above background,this article used hydrothermal method to grow manganese carbonate cubic crystal on the nickel foam electrode,and then modified a layer of iron hydroxide on the surface of manganese carbonate cubic crystal by electrodeposition method to prepare Fe（OH）₃/Mn CO₃-NF self-supporting electrode.When the electrolyte was 1 M KOH and the current density is 10 m A/cm²,the overpotential was only 213 m V,and the Tafel slope was 31.8 m V/dec.In the chronopotential stability test,the current density of 10 m A/cm² can be stable for more than 23 hours,and the effect remains basically unchanged.We have also grown the Co Se nanosheet cluster structure on the copper foam substrate by a simple one-step electrodeposition method.Through the electrochemical test,the current density was 10 m A/cm²,the overpotential was 252 m V,and the Tafel slope was 66.5 m V/dec.After a series of characterizations,it was found that the Se element gradually detaches from the surface during the electrochemical process of Co Se,and the Co Se nanosheets clusters were transformed into CoOOH hexagonal nanoplates containing Se defects,indicating that the real active center was CoOOH during oxygen evolution reaction process.This kind of defect-containing CoOOH hexagonal nanoplates exhibits excellent electrocatalytic water oxidation performance.