Doping And Surface Modification Of Carbon Cloth And Its Electrocatalytic Performance For Oxygen Evolution Reaction

Currently,the supply of energy mainly depends on non-renewable and polluting fossil energy.With the increasing demand for energy and the continuous consumption of fossil energy,people began to study green,renewable new energy.The metal-air battery and water cracking technology have received extensive attention because of their efficient and green energy conversion,and are considered as alternatives to fossil fuels.Oxygen evolution reaction（OER）is an important semi-reaction of reversible metal-air battery and electrolyzer technology,but it has slow kinetics.Therefore,an efficient electrocatalyst is needed to increase energy conversion efficiency.The precious metal catalysts currently used are expensive and have scarce reserves,which restricts their large-scale application.It is imperative to study OER electrocatalysts that are cheap and readily available and have excellent performance.Carbon cloth is woven from carbon fiber,which has the characteristics of high stability,high conductivity,flexibility,and easy surface modification.It is considered to be the next-generation catalyst to replace precious metal catalysts.In this paper,by modifying the surface of commercial carbon cloth,in addition to maintaining the original high conductivity and flexibility,the OER active site was introduced,a high-performance self-supporting OER catalyst was prepared,and obtained through various characterization and testing techniques The chemical composition,microstructure and electrochemical performance of the catalyst.The main contents and conclusions are as follows:（1）The functionalization and surface porosization of commercial carbon cloth and its electrocatalytic oxygen evolution performance.First,a commercial carbon cloth was used as the positive electrode,and a platinum wire was used as the negative electrode in a mixed acid solution（sulfuric acid:nitric acid=1:1）for 10 minutes to introduce a large number of oxygen-containing functional groups and obtain a large number of defective carbon atoms.Then,the oxidized carbon cloth was calcined at900℃ for 5 minutes in a hydrogen atmosphere.At high temperatures,the defective carbon atoms and hydrogen gasify to produce hydrocarbons,which makes the surface of the carbon cloth porous.The activated carbon cloth introduced a large number of defects and oxygen-containing functional groups as the active sites of OER,and the porous surface increased the contact between the active sites and the reactants in the electrolyte(electrochemical active area ECSA=27.25 m F cm^-2).The resulting activated carbon cloth showed excellent OER electrocatalytic performance in alkaline solution(η₁₀=350 mV,Tafel slope=127 mV dec^-1),while maintaining the stability of the carbon cloth before activation(η₁₀ increases by 10 mV after 10 h).（2）Research on heteroatom doping,surface porosification and electrocatalytic oxygen evolution of commercial carbon cloth.First,a commercial carbon cloth was used as the positive electrode,and a platinum wire was used as the negative electrode in a mixed acid solution（sulfuric acid:nitric acid=1:1）for 10 minutes to introduce a large number of oxygen-containing functional groups and obtain a large number of defective carbon atoms.Then,the commercial carbon cloth was calcined at 600℃ for5 minutes in an ammonia atmosphere.At high temperatures,the defective carbon atoms not only undergo a gasification reaction with ammonia gas to make the surface of the carbon cloth porous,but also introduce a large amount of nitrogen atoms into the carbon skeleton.A large number of defects and doped nitrogen atoms introduced after activation are the active sites of OER,which further improves the electrocatalytic activity of carbon cloth(η₁₀=346 mV,Tafel slope=78 mV dec^-1),and at lower temperatures Compared with the previous activation treatment,the stability of the carbon cloth was further maintained(η₁₀ increased by 14 mV after 20 h).This paper provides a simple and efficient strategy for the activation of commercial carbon cloth,and also provides a potential alternative for OER precious metal electrocatalysts,laying a good foundation for the practical application of metal-air batteries and water cracking technology.