Nitrogen-incorporation activates NiFeO x catalysts for efficiently boosting oxygen evolution activity and stability of BiVO 4 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 _x catalysts for significantly enhancing the oxygen evolution activity and stability of BiVO ₄ photoanodes, and the photocurrent density has been achieved up to 6.4 mA cm ^-2 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 _x 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 ₄ for restraining V ⁵⁺ 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.
(© 2021. The Author(s).)