Co-Doped Mn3 O4 Nanocubes via Galvanic Replacement Reactions for Photocatalytic Reduction of CO2 with High Turnover Number

Abstract

The synthesis of Co-doped Mn₃ O₄ nanocubes was achieved via galvanic replacement reactions for photo-reduction of CO₂ . Co@Mn₃ O₄ nanocubes could efficiently photo-reduce CO₂ to CO with a remarkable turnover number of 581.8 using [Ru(bpy)₃ ]Cl₂ ⋅ 6H₂ 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 Mn₃ O₄ , providing catalytic active sites during CO₂ reduction reactions, which facilitate the separation and migration of photogenerated charge carriers, further benefiting the outstanding photocatalytic performance of CO₂ reduction. Density functional theory calculations revealed that the decreasing of conduction band maximum in Co@Mn₃ O₄ was beneficial to the electron attachment from the excited sensitized molecule, which promoted photocatalytic reduction of CO₂ .

Keywords: CO2 reduction; density functional theory; galvanic replacement reactions; nanocubes; photocatalysis.