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.