Dual Vacancy-Regulated Pathway of Photoreduction of CO2 on Bi19S27Cl3 Nanorods into Multi-Carbon Solar Fuels

Modulation of dual bismuth (Bi) and sulfur (S) vacancies on Bi19S27Cl3 nanorods was successfully utilized for efficient photoconversion of CO₂ into ethane (C₂H₆) as the dominant product with electron-based selectivity as high as 88.6% in the presence of water vapor. The introduction of Bi and S dual vacancies typically promote the adsorption and activation of CO₂ molecules, while simultaneously lowering the energy barrier for the hydrogenation of *C1 intermediates and subsequent C1-C1 coupling. A synergistic catalysis mechanism is proposed for the promising photoconversion of CO2. Sulfur vacancies enhance CO₂ adsorption and *CO generation, while bismuth vacancies make the adjacent S atoms more electronically accessible than the Bi atoms, resulting in highly reactive and promoting C-C coupling of *CO therein. This work elucidates the synergistic effects of cationic and anionic vacancies in CO₂ photoreduction, offering valuable insights for the development of advanced CO₂ photoreduction catalysts.