The Role of W ↔ N Electron Transport Channel\nin Potassium-Doped WO<sub>3</sub>/g‑C<sub>3</sub>N<sub>4</sub> Nanocomposites for Light-Assisted Electrocatalytic Oxygen and Hydrogen\nEvolution Reactions: Decoding the

This study meticulously brings forth\nsignificant insights into\nthe efficacy of the potassium (K)-incorporated WO<sub>3</sub>/g-C<sub>3</sub>N<sub>4</sub> (K-WO<sub>3</sub>/K-gCN) system in facilitating\nelectrocatalytic oxygen and hydrogen evolution reactions (OER and\nHER) in alkaline and acidic environments, respectively. The study\nfound that the system achieved a minimum Tafel slope of 84 mV dec<sup>–1</sup> for the OER and 25 mV dec<sup>–1</sup> for\nthe HER under illumination. The -C-N-K- linkage was found to greatly\nfacilitate carrier transportation in gCN units. Additionally, the\ninterfacial W↔N channels provide easy carrier migration pathways,\nleading to improved electrocatalytic performance in the system under\nvisible light. We identified that for the OER, a unidirectional transfer\nof electrons takes place from N → W, i.e., from K-gCN to K-WO<sub>3</sub>, whereas for HER, the electron transfer takes place from\nW → N, i.e., K-WO<sub>3</sub> to K-gCN. These mechanisms were\nexplained based on the S-scheme interfacial charge transfer processes\nin a heterojunction, where holes regulate the OER process, and electrons\nplay a primary role in the HER. Additionally, the study identified\nC sites near nitrogen vacancies as responsible for initiating the\nOER and HER in the K-WO<sub>3</sub>/K-gCN system.