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-π 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 π system of the pyrene group with both the g-C₃N₄ surface and the Co-pyridyl moiety of the catalysts.