Optimizing water dissociation dehydrogenation process via Sn single atom incorporation for boosting photocatalytic CO2 methanation

The conversion of CO2 into value-added methane (CH4) via light-driven processes represents a promising strategy for mitigating energy scarcity and curtailing CO2 pollution. However, the intricate reaction kinetics of multiple electron-proton coupling processes remain a significant challenge. During the CO2 photoreduction process, the promotion of proton production from water dissociation for CH4 generation has been overlooked. Herein, Co3O4 is modified by Sn single atoms to realize selective CH4 production from CO2 photoreduction. The introducing of Sn induces generation of oxygen vacancy and adjacent low-valence Co (Co2+), which favors CO2 adsorption and activation by virtue of the reduced steric hindrance and enriched electrons at Co2+ sites. Specifically, Sn single atoms serve as H2O dissociation sites, accelerating the production of protons and reducing the energy barrier of the rate-determining step. Our work endows a guideline for controlling CO2 photoreduction products' selectivity through the delicate design of active sites in catalysts and reaction kinetics optimization.