Momentous Roles of Ag nanoparticles in enhancing CO2 photoreduction activity of Z-scheme heterojunction Ag/Bi12SiO20/BiOBr composite film

The immobilization of highly-efficient catalyst has always been one key issue in the research and development of industrial catalysts for carbon dioxide reduction. In this work, a series of novel Ag/Bi 12 SiO 20 /BiOBr composite films with varying levels of Ag deposition have been successfully synthesized using in-situ photodeposition method. Photocatalytic CO 2 reduction experiments indicate that 1.5   wt.%-Ag/Bi 12 SiO 20 /BiOBr composite film demonstrates the highest CO generation rate (33.47 μmol∙m −2 ∙h −1 ) and cycle stability, exhibiting the 1.62-fold increase after the incorporation Ag nano-particles (NPs). Characterization tests reveal that the presence of Ag NPs not only brings about the red-shift phenomenon of light absorption to extend and enhance visible-light response, but also acts as photo-generated carrier recombination center between Bi 12 SiO 20 and BiOBr to create unique Z-scheme charge transport pathway. More importantly, the Schottky barrier effect between Ag and semiconductors is conducive to improving the effective separate of photogenerated charges, improving photocatalytic CO 2 reduction. Our findings should offer valuable guidance for the research and development of construction heterostructures and noble metal deposition modification strategy for solar-driven CO 2 reduction photocatalyst system.