Mn Single-Atom Photocatalyst Enables Efficient Photocatalytic Reduction of CO₂

Photocatalytic conversion of CO₂ into fuels with H₂O as a proton source is recognized as a promising strategy for CO₂ utilization. However, past efforts have mainly been devoted to the CO₂ reduction reaction and overlooked essential water dissociation that provides a proton source. Herein, the Mn₁/PCN-N_V photocatalyst with Mn-N₃ coordination by incorporating Mn single atoms into a polymeric carbon nitride (PCN) framework endowed with nitrogen vacancies (N_V) is developed for CO₂ 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 H₂O and the activation of CO₂, 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.