Mn Single-Atom Photocatalyst Enables Efficient Photocatalytic Reduction of CO2

Photocatalytic conversion of CO 2 into fuels with H 2 O as a proton source is recognized as a promising strategy for CO 2 utilization. However, past efforts have mainly been devoted to the CO 2 reduction reaction and overlooked essential water dissociation that provides a proton source. Herein, the Mn 1 /PCN-N V photocatalyst with Mn–N 3 coordination by incorporating Mn single atoms into a polymeric carbon nitride (PCN) framework endowed with nitrogen vacancies (N V ) is developed for CO 2 photoreduction. It is revealed that N V induces an unsaturated environment for coordinating the Mn single atoms, which results in a highly localized surface electron distribution to promote charge carrier dynamics. The Mn sites simultaneously facilitate the dissociation of H 2 O and the activation of CO 2, which are favorable for the formation of the key intermediate *COOH. The designed photocatalyst demonstrates a significantly improved CO production rate of 29.63 μmol g –1 h –1 .