Tadios Tesfaye Mamo, Mohammad Qorbani, Adane Gebresilassie Hailemariam, Putikam Raghunath, C. C. Chu, Wen‐Hsin Yuan, Amr Sabbah, Yen‐Yu Wang, Shuo‐Yun Chang, MT Lin, Wei‐Yen Woon, Yu‐Jung Lu, Heng‐Liang Wu, Ken‐Tsung Wong, Kuei‐Hsien Chen, Li‐Chyong Chen
ABSTRACT Photocatalytic conversion of CO 2 into value‐added fuels offers a viable approach to combat climate change and address global energy demands. Here, we present a fluorine‐doped SnS 2 thin film with sulfur vacancy (i.e., S V ‐SnS 2 :F), prepared via thermal evaporation, post‐sulfurization, and fluorine ion‐implantation. Substitution of sulfur with fluorine and sulfur vacancy formation changes the product selectivity from CH 4 to CO with about 40‐fold enhanced yield and boosted internal quantum efficiency ( IQE ) of 0.52%. Transient absorption, in situ near‐ambient pressure X‐ray photoelectron, and in situ Fourier transform infrared spectroscopies, along with first‐principles density functional theory calculations, suggest that nearest‐neighbor Sn to F serves as an active site and stabilizes the *COOH intermediate. Our findings shed light on how F doping activates the nearby elements and its crucial role in intermediate stabilization toward selectivity change in a heterogeneous photocatalysis process.