Heterobimetallic NiFe Complex for Photocatalytic CO 2 Reduction: United Efforts of NiFe Dual Sites

Catalytic CO 2 reduction poses a significant challenge for the conversion of CO 2 into chemicals and fuels. Ni–Fe carbon monoxide dehydrogenase ([NiFe]-CODH) effectively mediates the reversible conversion of CO 2 and CO at a nearly thermodynamic equilibrium potential, highlighting the heterobimetallic cooperation for the design of CO 2 reduction catalysts. However, numerous NiFe biomimetic model complexes have realized little success in CO 2 reduction catalysis, which underscores the crucial role of precise bimetallic configuration and functionality. Herein, we presented a heterobimetallic NiFe complex for the photocatalytic reduction of CO 2 to CO, demonstrating significantly enhanced catalytic performance compared to the homonuclear NiNi catalyst. Photocatalytic and mechanistic investigations revealed that with the assistance of a redox-active phenanthroline ligand, NiFe achieves dual-site activation of CO 2 through a pivotal intermediate, Ni II (μ-CO 2 2– -κC:κO)Fe II, where the Lewis acidity of the Fe II site plays an important role, as corroborated in the homonuclear FeFe system. This study introduces the first heteronuclear NiFe molecular catalyst capable of efficiently catalyzing the reduction of CO 2 to CO, deepening insights into heterobimetallic cooperation and offering a novel strategy for designing highly active and selective CO 2 reduction catalysts.