• • The optimized 1.5% Ag/Bi2MoO6/BiOBr film achieves a CO production rate of 13.65 μmol/(g·h), representing a significant enhancement over unmodified films, which is critical for industrial-scale CO2 conversion efficiency.
• • Photocurrent and impedance measurements confirm superior charge separation in Ag-modified composites, directly correlating with reduced electron-hole recombination and higher photocatalytic activity.
• • A non-linear relationship between Ag loading and photocatalytic efficiency was observed, with an initial increase followed by a decline, indicating an optimal Ag content (1.5%) for maximizing LSPR and charge transfer while avoiding excessive coverage that blocks active sites.
• • The Z-scheme heterojunction mechanism, facilitated by Ag as an electron mediator, enables efficient spatial separation of redox sites, which is essential for achieving high selectivity and yield in CO2 photoreduction.