摘要
The development of non-precious,acid-stable,oxygen reduction reaction(ORR)electrocatalysts can significantly aid the commercialization of proton exchange membrane fuel cells(PEMFCs).We report a survey of the ORR electrocatalysis on 3d metal substituted(M=Mn,Fe,Co)molybdenum and tungsten nitrides in acidic environments.We find that molybdate catalysts are more active than tungstates,with the specific activity depending on the chemistry of the substituted 3d metal.In both families,more electronegative 3d metals led to higher ORR activity(i.e.,Co>Fe>Mn).We attribute this result to the ability of the more electro negative 3d metal to withdraw electro ns from the Mo-or W-based active sites,effectively oxidizing the metal centers of the catalysts.Based on our observation,future nitride ORR electrocatalysts can be further optimized by oxidizing the Mo sites further by,for example,addi ng eve n more electro negative dopa nt metals or in corporati ng anion vaca ncies.
基金
We thank Professor Francis J.DiSalvo(Cornell)for valuable discussions and use of his laboratory facility.The work is supported by the National Science Foundation(NSF)under Grant No.CHE-1805400
This work used the Cornell Center for Materials Research Shared Facilities which were supported through the NSF Materials Research Science and Engineering Center program(DMR-1120296).
