Metal–oxygen hybridization in Agcluster/TiO2 for selective CO2 photoreduction to CH4.

• Strong metal–oxygen hybridization was successfully incorporated in Ag cluster /TiO 2. • Ag cluster /TiO 2 shows a high photocatalytic CH 4 generation activity and selectivity. • Ag–O hybridization effectively optimizes photogenerated carrier dynamics. • Ag–O hybridization promotes the multiple-proton–electron coupling transfer process. Selective photocatalytic reduction of CO 2 to CH 4 is one of the most efficient ways to achieve carbon neutralization. However, the formation of methane remains a challenge due to the slow multiple-proton-coupled electron transfer process and the involvement of various C1 intermediates. Herein, an Ag cluster /TiO 2 catalyst with Ag-O hybridization was synthesized by supporting Ag clusters on anatase phase TiO 2 microspheres for photocatalytic CO 2 methanation. The Ag cluster /TiO 2 sample presents an electron selectivity of 86 % for CH 4 production with a yield of 25.25 μmol g–1 h−1. Mechanistic study reveals that Ag clusters accelerate the separation and migration of photogenerated carriers, and enhance the adsorption of CO 2. Moreover, the Ag-O hybridization promotes the multiple-proton–electron coupling transfer process by effectively stabilizing intermediates and facilitating *CO hydrogenation to *CHO, resulting in selective CO 2 reduction to CH 4. This work provides a new insight into the development of selective photocatalytic conversion of CO 2 to methane by constructing supported cluster catalysts. [ABSTRACT FROM AUTHOR]