Zr4L6 Cage-Based Metal Boron-Imidazolate Materials for CO2 Photoreduction.

The structural tunability and dispersibility of cage-based catalysts make their construction via multifunctional moiety integration an effective strategy. Herein we show that enhanced catalytic performance for CO2 photoreduction can be achieved by anchoring active metal sites and boron-imidazolate ligands on versatile (Zr4L6)8- (L = embonate) cages. Three (Zr4L6)8- cage-based metal boron-imidazolate structures were successfully synthesized via hierarchical self-assembly and postsynthetic ion exchange, respectively. Through cocoordination of the (Zr4L6)8- cage and boron-imidazolate ligands with metal ions, (Zr4L6)8- cages can be organized into various structures, including 0D PTC-390-Co, 2D layer PTC-391-Cu, and the combination of ionic pair cage PTC-373-Co. When applied to photocatalytic CO2 reduction under visible light, PTC-373-Co exhibited the highest activity, achieving a CO production rate of 970 μmol g-1 h-1 with a selectivity of 90% for CO over H2. These results suggest that cage-based catalysts represent a promising avenue for photocatalysis.