Multi‐Scale Silver Clusters Synergistically Boosting CO ₂ Photoreduction over SrTiO ₃

ABSTRACT Strontium titanate (SrTiO 3 ) has great potential for Photocatalytic CO 2 reduction because of its well‐aligned conduction/valence band edges, excellent chemical stability, and non‐toxic and low‐cost. Nevertheless, SrTiO 3 still confronts three critical bottlenecks of limited visible‐light harvesting ability, low specific surface area, and rapid surface carriers’ recombination rate. Herein, a multi‐scale silver‐cluster synergistic modification strategy was proposed to decorate SrTiO 3 (SrTiO 3 ‐Ag). Ultrafine Ag clusters (1∼3 nm) can extend the optical absorption into the visible region through their high surface energy, while larger Ag clusters (∼5 nm) can serve as carrier‐trapping centers via stable electronic states and Schottky barriers at the interface, thereby prolonging carrier lifetime and optimizing CO 2 adsorption/activation pathways. Under 300 W Xe light irradiation, the optimized composite delivers efficient CO 2 ‐to‐CO conversion activity, which was much higher than that of pristine SrTiO 3 . A possible photocatalytic mechanism was proposed based on a series of experimental characterizations. This work offers a new design principle for efficient and durable solar‐driven CO 2 ‐reduction photocatalysts.