Uncovering the synergistic photocatalytic behavior of bimetallic molecular catalysts

Bimetallic catalysts usually exhibit better performance than monometallic catalysts due to synergistic effect. However, there is a lack of exploring the synergistic effect on catalytic performance caused by the introduction of inactive metal ion. In this work, we design a molecular model system that can precisely regulate the metal site number and catalytic property. When these molecular metal compounds are used as homogeneous catalysts for photocatalytic CO2 reduction, the dinuclear heterometallic CuNi-L2 shows the highest CO2-to-CO conversion, which is 2.1 and 3.0 times higher than that of dinuclear homometallic Ni2-L2 and mononuclear Ni-L1. Density functional theory calculations demonstrate that, in CuNi-L2, the introduction of inactive CuII is easier to promote the photo-generated electrons transferring to the coupled active NiII site to achieve the highest activity. In addition, this work also provides insights to design and construct more efficient bimetallic catalysts in future.