Modulating Chloride Adsorption for Efficient Chloride-Mediated Methane Conversion over Tungsten Oxide Photoanode

Utilizing alkali chlorides as the chloride source in chloride-mediated methane activation represents an efficient approach for CH4 valorization. Nevertheless, great challenges remain due to the restricted catalytic activity and durability. Here, we present a photoelectrochemical approach for chloride-mediated methane conversion to C1 products using WO3 with surface oxygen vacancies (OV). Theoretical calculations indicate that oxygen vacancies play a crucial role in enhancing chloride adsorption to facilitate methane activation. The engineered WO3–OV photoanode exhibits enhanced catalytic performance in comparison to the pristine counterparts, attaining a Faradaic efficiency of 94.5% for C1 products (methyl chloride, methanol, formic acid, and formaldehyde) at 0.9 V vs RHE. This performance corresponds to a total production rate of 139.2 mmol g–1 h–1 for the C1 products. Furthermore, the system is capable of achieving a high CH4 conversion efficiency of 11.8%. This work emphasizes the pivotal role of photoanode design and surface engineering in facilitating methane conversion.