Surpassing electrocatalytic limit of earth-abundant Fe4+ embedded in N-doped graphene for (photo)electrocatalytic water oxidation

Developing highly active, cost-effective, and environmental friendly oxygen evolution reaction (OER) electrocatalysts facilitates various (photo)electrochemical processes. In this work, Fe3N nanoparticles encapsulated into N-doped graphene nanoshells (Fe3N@NG) as OER electrocatalysts in alkaline media were reported. Both the experimental and theoretical comparison between Fe3N@NG and Fe3N/NG, specifically including in situ Mossbauer analyses, demonstrated that the NG nanoshells improved interfacial electron transfer process from Fe3N to NG to form high-valence Fe4+ 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 Fe2O3, leading to high OER stability. As a result, the as-formed Fe4+@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 Fe2O3 nanoarray photoanode. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

The study presents Fe3N@NG as an efficient OER electrocatalyst, where the NG nanoshells enhance electron transfer from Fe3N to NG, improving catalytic efficiency and stability.