CH-π interaction boosts photocatalytic CO2 reduction activity of a molecular cobalt catalyst anchored on carbon nitride

The construction of efficient noble-metal-free systems for visible-light-driven CO2 reduction still remains a key challenge. Here, we report an efficient molecular hybrid system composed of a Co-PYN5 catalyst that contains a pyrene functionality that anchors on g-C3N4 dye surface via CH-pi interactions. This hybrid material achieves high turnover numbers (TONS) and turnover frequencies (TOFs) for visible light reduction of CO2 to CO of 533 and 95 h(-1) that are within the best reported up to now. The improved performance is rationalized in terms of the electronic coupling that takes place with the pi system of the pyrene group with both the g-C3N4 surface and the Co-pyridyl moiety of the catalysts.