Construction of Ag nanoparticle-decorated SnO₂/g–C₃N₄ S-scheme heterojunction for highly selective photoreduction of CO₂ to CO

The efficient photocatalytic reduction of CO₂ provides a promising route to mitigate greenhouse gas emissions. In this study, an S‑scheme heterojunction photocatalyst composed of Ag nanosheets and a SnO₂–g‑C₃N₄ binary system was constructed. The matched band structures of g‑C₃N₄ and SnO₂ facilitate S‑scheme charge transfer, significantly enhancing the separation efficiency and redox capability of photogenerated carriers. The incorporated Ag nanosheets further inject plasmon‑induced hot electrons into the heterojunction, broadening the light‑absorption range into the near‑infrared region and promoting carrier utilization. Remarkably, the catalyst exhibits high selectivity for CO production from CO₂ photoreduction in pure water, without the need for sacrificial agents. This work demonstrates a green and effective strategy for designing broad‑spectrum plasmon‑enhanced S‑scheme photocatalytic systems for solar‑driven CO₂ conversion.