Preparation And Electrocatalytic Performance Of Perovskite/N-carbon Composite Powders

Perovskite oxide is widely used as an effective electrode material in the air electrode due to its unique defect structure,rapid oxygen mobility and low cost.Porous N-contained carbon materials have excellent conductivity,specific surface area and more active sites,which can be the ideal substrate for catalysts.As a result,combining the perovskite with porous N-contained carbon substrat to form composites can not only effectively prevent the perovskite particles aggregation,improve electrical conductivity,but also produce new synergistic effects between them,and has bright application prospects.In this paper,we synthesized the 3D nitrogen-doped graphene with ethylenediamine acted as the nitrogen source by hydrothermal method.And two kinds of biocarbon materials were prepared by hydrolysis and pyrolysis,respectively,wherein the okara was as the sources of carbon and nitrogen.The structure and phase of N-contained carbon materials were analyzed by means of XRD and SEM;The samples for the performance of oxygen reduction reaction was characterized by RDE technique.Meanwhile,the sample was applied as a cathode catalyst to zinc-air battery and its electrochemical properties were studied.The results show that the N-contained biocarbon prepared by pyrolysis has the larger specific surface area and best catalytic activities.We successfully prepared the LaMnO₃/biocarbon composite powder of different content of biocarbon through combing the N-contained biocarbon prepared by pyrolysis with nitrate solution by a sol-gel method.The results show that perovskite creats more oxygen defects after the combination with biocarbon;The subtrate of N-contained carbon material can not only greatly reduced the agglomeration of nanoparticles,but also played an important role in electron transport and the adsorption of oxygen molecule,and the N element in biocarbon had a significant contribution toward its ORR performance.The oxygen reduction performance tests demonstrat that the compound powder has excellent electrocatalytic activity when the percentage of biocarbon in composites is 10 wt%.