Design Of Modified Carbon Fiber Paper Supported Pt Electrode For Electrocatalysis

Carbon fiber paper loaded electrodes,also known as gas diffusion electrodes,have a wide range of applications in fuel cell,metal air cell and other fields of electrocatalysis.As an important part of the electrode,carbon fiber paper plays an important role in gas diffusion electrode performance,electron conduction and catalyst load.In this study,a new gas diffusion electrode with synergistic electrocatalytic properties was prepared by modifying carbon fiber paper and using electrodeposited nano-Pt,and the electrochemical properties such as concentrated nitric acid reduction and oxygen reduction were studied.Carbon fiber paper was modified by electrochemical cyclic voltammetry activation and high-temperature treatment（Ar）.The results showed that the surface roughness of modified carbon fiber paper increased obviously,and the higher treatment temperature made the structure of carbon fiber microlithography change,and the content of edge defects increased.The oxygen content on the carbon fiber surface decreased obviously,but the nitrogen content changed little.In the electrochemical reduction reaction of 4 M concentrated nitric acid,the reduction peak current density of the modified carbon fiber paper electrode reached 507.8m A cm^-2,while the activated carbon fiber paper was only 464.2m A cm^-2,which proved that the electrocatalytic activity of carbon fiber paper could be significantly improved in the high-temperature treatment.Gas diffusion electrode（Pt/ACFP）was prepared by the electrodeposition of nano-Pt on modified carbon fiber paper by cyclic voltammetry.It was found that the growth of Pt nanoparticles was more uniform in the Pt/ACFP700electrode,with the size ranging from 50～100 nm.Pt nanoparticles mainly grew along the crystal surface[111],with high crystallinity.Compared with Pt/CFP,The ECSA of Pt/ACFP700 electrode can reach 80.03 m²g_Pt^-1,showing excellent electrochemical activity.Study on electrocatalytic performance of gas diffusion electrode.The reduction activity of gas diffusion electrode was studied in 4 M concentrated nitric acid.It was found that the peak of NH₃formation was observed in Pt/ACFP700 electrode at a low potential,and its current density was 110.6 m A mg_Pt^-1,while the current density of unmodified carbon fiber paper supported nano-Pt electrode（Pt/CFP）was only 37.6m A mg_Pt^-1.At high potential,the HNO₂autocatalytic reduction peak can be observed,and its maximum current density is 1058.9 m A mg_Pt^-1,indicating that the new gas diffusion electrode had a high synergistic electrocatalytic concentrated nitric acid reduction activity.The gas reduction products are NO and N₂O,and NH₃is not detected.At the same time,the oxygen reduction performance of gas diffusion electrode was studied under acidic and alkaline conditions.The results of oxygen reduction test showed that the prepared gas diffusion electrode had outstanding oxygen reduction catalytic activity.Under alkaline conditions,the oxygen reduction initiation potential of Pt/ACFP700 electrode reached 0.965 V and showed excellent electrochemical stability.The study of this new gas diffusion electrode provides a new idea for the design of high-performance electrode materials in the field of electrocatalysis.