Co‐Doped Mn3O4 Nanocubes via Galvanic Replacement Reactions for Photocatalytic Reduction of CO2 with High Turnover Number

Abstract The synthesis of Co‐doped Mn 3 O 4 nanocubes was achieved via galvanic replacement reactions for photo‐reduction of CO 2 . Co@Mn 3 O 4 nanocubes could efficiently photo‐reduce CO 2 to CO with a remarkable turnover number of 581.8 using [Ru(bpy) 3 ]Cl 2 ⋅ 6H 2 O as photosensitizer and triethanolamine as sacrificial agent in acetonitrile and water. The galvanic replaced Co species are homogeneously distributed at the outer surface of Mn 3 O 4 , providing catalytic active sites during CO 2 reduction reactions, which facilitate the separation and migration of photogenerated charge carriers, further benefiting the outstanding photocatalytic performance of CO 2 reduction. Density functional theory calculations revealed that the decreasing of conduction band maximum in Co@Mn 3 O 4 was beneficial to the electron attachment from the excited sensitized molecule, which promoted photocatalytic reduction of CO 2 .