Linking oxidative and reductive clusters to prepare crystalline porous catalysts for photocatalytic CO ₂ reduction with H ₂O

Abstract

Mimicking natural photosynthesis to convert CO ₂ with H ₂O into value-added fuels achieving overall reaction is a promising way to reduce the atmospheric CO ₂ level. Casting the catalyst of two or more catalytic sites with rapid electron transfer and interaction may be an effective strategy for coupling photocatalytic CO ₂ reduction and H ₂O oxidation. Herein, based on the MOF ∪ COF collaboration, we have carefully designed and synthesized a crystalline hetero-metallic cluster catalyst denoted MCOF-Ti ₆Cu ₃ with spatial separation and functional cooperation between oxidative and reductive clusters. It utilizes dynamic covalent bonds between clusters to promote photo-induced charge separation and transfer efficiency, to drive both the photocatalytic oxidative and reductive reactions. MCOF-Ti ₆Cu ₃ exhibits fine activity in the conversion of CO ₂ with water into HCOOH (169.8 μmol g ⁻¹h ⁻¹). Remarkably, experiments and theoretical calculations reveal that photo-excited electrons are transferred from Ti to Cu, indicating that the Cu cluster is the catalytic reduction center.

Abstract

A crystalline hetero-metallic cluster catalyst based on a covalent organic framework strategy is reported. The catalyst can facilitate both photocatalytic oxidative and reductive reactions leading to efficient production of HCOOH from CO2 and H2O.