| Abstract: | Developing highly active,cost-effective,and environmental friendly oxygen evolution reaction(OER)electrocatalysts facilitates various(photo)electrochemical processes.In this work,Fe_3N nanoparticles encapsulated into N-doped graphene nanoshells(Fe_3N@NG) as OER electrocatalysts in alkaline media were reported.Both the experimental and theoretical comparison between Fe_3 N@NG and Fe_3N/NG,specifically including in situ Mossbauer analyses,demonstrated that the NG nanoshells improved interfacial electron transfer process from Fe_3N to NG to form high-valence Fe~(4+) ions(Fe~(4+)@NG), thus modifying electronic properties of the outer NG shells and subsequently electron transfer from oxygen intermediate to NG nanoshells for OER catalytic process.Meanwhile,the NG nanoshells also protected Fe-based cores from forming OER inactive and insulated Fe_2O_3,leading to high OER stability.As a result,the as-formed Fe~(4+) @NG shows one of the highest electrocatalytic efficiency among reported Fe-based OER electrocatalysts,which can as well highly improve the photoelectrochemical water oxidation when used as the cocatalysts for the Fe_2O_3 nanoarray photoanode. |
