Boosting Photocatalytic CO 2 Reduction Over In‐Doped Bi 4 O 5 Br 2 : Synergistic Bandgap Engineering and Charge Separation

ABSTRACT Photocatalytic CO 2 reduction represents a viable approach to achieving carbon neutrality through fuel production. Nonetheless, the practical deployment of photocatalysts is frequently hampered by the rapid recombination of photogenerated charge carriers. In this investigation, a one‐pot solvothermal method was used to synthesize In‐doped Bi 4 O 5 Br 2 photocatalysts. Comprehensive characterizations demonstrate that the electronic structure is effectively modulated by In 3+ doping, resulting in a narrowed bandgap. Crucially, the recombination of photogenerated electron–hole pairs is suppressed through the introduction of dopant‐induced energy levels. The 15In‐Bi 4 O 5 Br 2 sample displays the optimal photocatalytic CO 2 reduction activity, producing CO at a rate of 4.67 µmol g −1 h −1 , which is approximately 2.3 times higher than that of unmodified Bi 4 O 5 Br 2 . This remarkable enhancement is attributed to the synergistic effects of an optimized band structure and improved charge separation efficiency induced by In doping. This work provides valuable insights into the rational design of bismuth‐based materials for sustainable CO 2 conversion.