Promoting Photocatalytic CO 2 Methanation by the Construction of Cooperative Copper Dual-Active Sites

Selective photocatalytic CO 2 methanation provides an attractive avenue to address energy and environmental issues. However, impediments such as the sluggish adsorption and activation of CO 2 and H 2 O molecules, along with unexpected intermediate desorption, greatly restrict the activity and selectivity of photocatalytic CO 2 methanation. To address these issues, we devised a dual-active site catalyst comprising Cu single atoms (SAs) and nanoclusters (NCs) supported on defective TiO 2 (Cu 1+NCs /BT). As a result, a remarkable CH 4 selectivity of 98% with a yield of 19.63 μmol g cat. –1 h –1 can be obtained over the as-prepared Cu 1+NCs /BT in pure water. Mechanistic studies reveal the enhanced performance could be ascribed to the synergistic effect of the Cu dual-active sites, where Cu SAs adsorb and activate CO 2, while Cu NCs boost H 2 O adsorption and dissociation for *H coverage. Additionally, the adjacent Cu dual-active site could jointly stabilize the *CO intermediate and reduce the energy barrier for *CO protonation, promoting the multielectron transfer process.