Nitrogen-incorporation activates NiFeO catalysts for efficiently boosting oxygen evolution activity and stability of BiVO photoanodes.

Developing low-cost and highly efficient catalysts toward the efficient oxygen evolution reaction (OER) is highly desirable for photoelectrochemical (PEC) water splitting. Herein, we demonstrated that N-incorporation could efficiently activate NiFeO catalysts for significantly enhancing the oxygen evolution activity and stability of BiVO photoanodes, and the photocurrent density has been achieved up to 6.4 mA cm at 1.23 V (vs. reversible hydrogen electrode (RHE), AM 1.5 G). Systematic studies indicate that the partial substitution of O sites in NiFeO catalysts by low electronegative N atoms enriched the electron densities in both Fe and Ni sites. The electron-enriched Ni sites conversely donated electrons to V sites of BiVO for restraining V dissolution and improving the PEC stability, while the enhanced hole-attracting ability of Fe sites significantly promotes the oxygen-evolution activity. This work provides a promising strategy for optimizing OER catalysts to construct highly efficient and stable PEC water splitting devices.