Preparation And Characterization Of Pt-Ag/C Electrocatalyst For Orr And Application In Zinc-air Fuel Cell

The alkali zinc–air fuel cells(ZAFC) is one of the most hot esearch in thefield of energy battery,because of its high energy, green for environment, andother unique advantages,. A core area of the alkali zinc–air fuel cell researchis the gas diffusion cathode catalyst for efficient oxygen reduction electrode.In this paper, we developed a high oxygen reduction catalytic activity ofcarbon supported Pt-Ag nano alloy catalyst to solve the question that existingoxygen reduction catalysts were not high catalytic activity and poordurability.Through exploring the factors that affect the structure and catalyticperformance of the process condition,we confirmed the best synthesis processcondition:catalyst carrier120°C acidified carbon black; metal salt solution ofthe system is Ag(NH3)2OH and H2PtCl6solution system; the pH of thereaction system is10;the reaction system in the alcohol-water ratio is2:1.Through TEM and SEM graph, we confirmed that the particle size of metal particles was about7nm,the surface of silica carrier uniform loaded.We successfully synthesized Pt20Ag80/C Pt30Ag70/C Pt40Ag60/C andPt50Ag50/C four kinds of platinum silver atomic ratio of the catalyst bychanging the ratio of platinum and silver., Through XRD and XPS, welearned that the synthesis of metal particles in the alloy solid solution withsilver as the solvent, platinum is the solute.Electrochemical characterizationof carbon supported four different nano-alloy catalysts for the oxygenreduction reaction had shown a high electrocatalytic activity, their oxygenreduction path is the four-electron reaction path. Compared with Commercialcatalysts Pt/C,Pt30Ag70/C electrochemical catalysts had the best oxygenreduction performance.Four kinds of catalysts assembled into zinc-air fuel cell,in charge anddischarge performance test, the cell capacity and discharge time are betterthan the cell produced by commercial Pt/C catalyst.Among the five cells,thecell using the Pt30Ag70/C electro-catalyst shows the best performance itsdischarge time is3.4h,its discharge capacity is520.2mAh.