Integrated Carbon Layer and CoNiP Cocatalyst on SnWO4 Film for Enhanced Photoelectrochemical Water Splitting

α‐SnWO4 is a promising semiconductor for solar water splitting, however, its performance is limited by weak water oxidation and poor charge transfer. In this study, we employ a vapor deposition method to uniformly implement a carbon layer onto the surface of SnWO4 coupled with a CoNiP cocatalyst, successfully constructing the integrated CoNiP/C/SnWO4 film photoanode and alleviating the oxidation of Sn2+ when loading electrocatalyst. Incorporating the carbon layer enhances the interface charge conduction behavior between the SnWO4 substrate and the CoNiP cocatalyst, thereby mitigating charge recombination. The synergistic interplay between the carbon layer and CoNiP leads to a remarkable achievement, as evidenced by the photocurrent of 1.72 mA cm−2 (1.23 V vs. RHE) observed for SnWO4 film measured in 0.2 M potassium phosphate buffer solution. In this work, we demonstrate the viability of tailoring SnWO4 photoanode and provide valuable insights for prospective advancements in modifying SnWO4 photoanode.