Research progress of H2 and CO electrochemical oxidation mechanisms in metal and doped ceria system
The application of metal-rare earth doped ceria anode is one of the most important strategies for the moderate and low temperature solid oxide fuel cells(SOFC).The mixed ionic and electronic conductor(MIEC)characteristic of doped ceria expands the reaction interface and complicates the reaction mechanism.This article reviewed the electrochemical oxidation mechanism of H2 and CO in metal and doped ceria system.It was pointed out that the Ni/YSZ-like H spillover mechanism was dominant in the H2 electrochemistry.For the CO electrochemistry,combined with the predominant Marse-van Krevelen(MvK)type mechanism in the CO catalytic reaction and the reverse process of the CO2 electrochemical reduction reaction,it was predicted that the charge transfer step mainly occurred in the oxygen vacancy formation and the CO2 formation reactions.In the MIEC type reaction mechanism,the main difference in the H2 oxidation reaction pathways was the difference of H2 dissociation adsorption site.The CO oxidation reaction pathway can be categorized into two modes based on the adsorption site:directly reacting with CeO2 lattice oxygen to generate CO2 or generating carbonate intermediates,and the charge transfer step involved carbonate formation and CO2 formation reactions.In summary,H2 electrochemical oxidation was dominated by H spillover,while the dominant reaction mechanism of CO electrochemical oxidation was still unclear and required further study.This article was instructive for clarifying the reaction mechanisms of Ni/YSZ and MIEC types in H2 and CO,as well as H2/CO hybrid fuel systems.
solid oxide fuel cellselectrochemistryoxidationreaction mechanismmixed ionic and electronic conductorceria-based oxidescatalysis
国家科技期刊平台
NSTL
万方数据
