Enhanced photoelectrochemical water splitting performance of α-FeO photoanodes through Co-modification with Co single atoms and g-CN.

The practical application of α-FeO in water splitting is hindered by significant charge recombination and slow water oxidation. To address this issue, a CoSAs-g-CN/FeO (CoSAs: cobalt single atoms) photoanode was fabricated in this study through the co-modification of CoSAs and g-CN to enhance photoelectrochemical (PEC) water splitting. The coupling between g-CN and α-FeO resulted in the formation of a heterojunction, which provided a strong built-in electric field and an additional driving force to mitigate charge recombination. Moreover, g-CN served as a suitable carrier for single atoms, which effectively anchored CoSAs through N/C coordination. The highly dispersed CoSAs provided abundant active sites, which further promoted surface holes extraction and oxidation kinetics, resulting in higher PEC performance and photostability. This study indicates the benefits of these collaborative strategies and provides more efficient designs for solar energy conversion in PEC systems.