Study On Synergistic Promotion Of Electrochemical Reaction By Atomic Dispersed Silver/Zinc

With the progress of human civilization,energy consumption in the world is becoming more and more serious.The development of new energy technologies with low price and high energy conversion efficiency has always been a hot topic for researchers.Zinc-air battery is a promising clean energy to replace fuel cell,but the slow cathode oxygen reduction reaction（ORR）and oxygen evolution reaction（OER）are difficult problems in scientific research.The current commercial catalysts for ORR and OER are Pt/C,Ru O₂ and Ir O₂.This paper by ZIF-8 precursor as the research object,in the preparation of highly active ORR catalyst and OER electricity as the goal,with the aid of ZIF-8 in carbide hole structure formed in the process of the preparation of the single nitrogen atoms dispersed zinc carbon catalyst and double nitrogen atoms dispersed silver/zinc carbon catalyst,and the morphology of the system structure characteristics and research electric catalytic performance.In this paper,based on the traditional preparation of ZIF-8 material,Zn SA/N-C catalyst material with single atom dispersion was prepared by solvothermal method by setting a reasonable amount of Zn（NO₃）₂·6H₂O.The results show that when the carbonization temperature reaches 1000℃,the dodecahedral structure of ZIF-8 provides active sites and electron transfer channels for zinc single atoms,and the half-wave potential of Zn SA/N-C-1000℃material is 0.8 V.Based on the preparation of ZIF-8 precursor,Ag/Zn-N-C catalyst material with diatomic dispersion was prepared by adsorption method.The effects of Ag single atom loading on the morphology,structure and ORR properties of Zn SA/N-C catalyst materials were investigated.A Kind of Ag/Zn-N-C-1000℃catalyst material with good oxygen reduction activity and zinc air battery cathode catalytic activity was obtained,and its oxygen reduction half-wave potential reached 0.87 V.The excellent ORR catalytic activity of Ag/Zn-N-C-1000℃is attributed to the generated diatomic Silver/Zinc dispersed active sites.ICP test determined that the content of Ag in Ag/Zn-N-C-1000℃sample accounted for 0.9 wt.%.The OER performance of ZnSA/N-C samples and Ag/Zn-N-C samples were studied,which further confirmed that the loading of Ag single atom on Zn SA/N-C materials improved the electrocatalytic performance.The overpotential of Ag/Zn-N-C-1000℃samples is better than that of commercial Ru O₂ catalyst at current densities of 10 m A cm^-2 and 100 m A cm^-2.