Heterogenization of a Dinuclear Cobalt Molecular Catalyst in Porous Polymers via Covalent Strategy for CO2 Photoreduction with Record CO Production Efficiency

Photocatalytic CO2 reduction into chemical fuels is a promising route for alleviating the energy crisis and environmental issues. However, reported catalysts still exhibit low catalytic efficiencies, which hinders the development of this important reaction. Herein, we report the heterogenization of a dinuclear cobalt molecular catalyst into two porous polymers (Co-2-P-1 and Co-2-P-2) using a covalent strategy for photocatalytic CO2 reduction. As a result, Co-2-P-1 with a phenyl group as the linker exhibited high catalytic performance for the photochemical CO2-to-CO conversion with a CO production rate of 568.8 mmol g(-1) h(-1) and turnover frequency (TOF) of 11.6 min(-1) (CO selectivity, 95.2%). More impressively, by extending the phenyl to biphenyl linker, the resulting Co-2-P-2 shows obviously enhanced photocatalytic efficiency for CO2 reduction to CO, with a record CO production rate of 1063.0 mmol g(-1) h(-1) and TOF of 23.6 min(-1) (CO selectivity, 94.9%) under a laboratory light source. Furthermore, Co-2-P-2 also shows outstanding catalytic activity for photocatalytic CO2 reduction under natural sunlight, with a CO production rate of 544.1 mmol g(-1) h(-1) and TOF of 12.1 min(-1) (CO selectivity, 97.2%). Systematic studies demonstrated that fast electron transfer from the photosensitizer to the catalyst greatly contributes to the superior catalytic activity of Co-2-P-2. [GRAPHICS] .