Nitrogen-incorporation activates NiFeOx catalysts for efficiently boosting oxygen evolution activity and stability of BiVO4 photoanodes

Abstract

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 BiVO₄ 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 BiVO₄ for restraining V⁵⁺ 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.

While solar-to-fuel conversion offers a renewable energy production strategy, photoelectrochemical water splitting requires further optimization. Here, authors examined nitrogen-doped NiFeO_x catalysts to improve the oxygen evolution activity and stability of BiVO₄ photoanodes.