Fluorine-expedited nitridation of layered perovskite Sr<sub>2</sub>TiO<sub>4</sub> for visible-light-driven photocatalytic overall water splitting.

Yu, Jinxing; Huang, Jie; Li, Ronghua; Li, Yanbo; Liu, Gang; Xu, Xiaoxiang · Nat Commun · 2025

basic_science · Level V

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Abstract

Photocatalytic overall water splitting is a promising approach for a sustainable hydrogen provision using solar energy. For sufficient solar energy utilization, this reaction ought to be operated based on visible-light-active semiconductors, which is very challenging. In this work, an F-expedited nitridation strategy is applied to modify the wide-bandgap semiconductor Sr<sub>2</sub>TiO<sub>4</sub> for visible-light-driven photocatalytic overall water splitting. Compared to the conventional nitridation approach, F-expedited nitridation introduces the desirable integration of a high concentration of N dopant for strong visible light absorption and a low concentration of defects (i.e. Ti<sup>3+</sup> and oxygen vacancies) for effective separation of photocarriers. After being coated with Ti-oxyhydroxide protection layer and deposited with RhCrO<sub>y</sub> cocatalyst, the product from F-expedited nitridation can stably run photocatalytic overall water splitting with apparent quantum efficiency of 0.39% at 420 ± 20 nm and solar-to-hydrogen efficiency of 0.028%. These findings justify the effectiveness of F-expedited nitridation strategy and serve as a guidance to upgrade the photocatalytic activity of many other wide-bandgap semiconductors.