Synchronizing directional photogenerated electrons and holes through Ag and Bi bimetallic modification toward sustained hydrogenation process in CO2 methanation reaction

Sustained photocatalytic hydrogenation of CO 2 molecules is crucial for the CO 2 methanation reaction. Synchronizing directional photogenerated charge carriers and regulating the activation and hydrogenation process of CO 2 molecules are key to achieving the efficient photocatalytic methanation of CO 2 . Herein, Ag–Bi bimetallic sites were designed and anchored on the surface of TiO 2 via a one-step solution impregnation reduction and applied for the photocatalytic conversion of CO 2 to CH 4 . The optimum 5 %Ag 90 Bi 10 -TiO 2 composite exhibited excellent photocatalytic performance for the photoreduction of CO 2 into CH 4 . The product selectivity of CH 4 reached up to 97.2 %, at a rate of 58.9 μmol·g −1 ·h −1 . In situ Kelvin probe force microscopy and diffuse reflectance infrared Fourier transform spectroscopy attributed the high selectivity of CH 4 to the coexistence of metallic Ag and Bi sites, which induced directional photogenerated electrons and hole transfer. Moreover, the synergistic function of Ag–Bi bimetallic active sites on TiO 2 facilitated the hydrogenation of *CO 2 – to CH 4 . The proposed strategy provides insight into the design of highly selective photocatalysts for the reaction of photocatalytic methanation of CO 2 .