Edge Activation of Inert Polymeric Carbon Nitride Matrix with Boosted Absorption Kinetic and Near-infrared Response for Efficient Photocatalytic CO2 Reduction
Reduction of CO2 into C1 feedstocks (e.g. CO) by utilizing solar energy has attracted increasing attention for the efficient production of renewable energy. While, a significant challenge in CO2 reduction is achieving with high conversion efficiency due to the high C=O dissociation energy of CO2 and difficultly inaccessible to the surface of photocatalyst. In the present contribution, we fabricate a polymeric carbon nitride (PCN) catalyst with hydroxyethyl group grafted in the edge via a facile bottom-up strategy, facilitating an efficient surface absorption of CO2, lowering the CO2 transformation energy barrier, accompanying with an exceptional extended optical absorption ability to near-infrared region as well as the increased of state density along the Fermi level. Thus, concentrated CO2 molecules are able to contact the surface of PCN and easily activated, enables an excellent CO production rate up to 209.24 μmolh-1g-1 in the modified PCN (i.e. 39.5 folds’ increase than pristine PCN) and a selectivity of 98.5% under the white LED light illumination, exceeding most of the PCN-based energy conversion system reported to date. Notably, this PCN matrix also exhibits photocatalytic CO production activity at the near-infrared region from 780 to 850 nm. These results pave the way to develop structured photocatalysts with easy accessibility of CO2 and broadband spectral response for efficient photocatalytic CO2 reduction.