Achieving efficient photoreduction of CO2 by simultaneously facilitating the splitting of H2O and the conversion of *CO intermediates

Abstract

Photocatalytic reduction of CO₂ with H₂O to hydrocarbon fuels is considered a promising approach to address environmental and energy challenges. However, the efficiency of CO₂ photoreduction remains unsatisfactory due to limitations in the reaction rates of CO₂ and H₂O. This study focuses on the development of defect and organic molecule (3,5-Diamino-1,2,4-triazole, DATZ) modified carbon nitride catalysts (g-CN-DZT) for enhancing the photoreduction of CO₂ with H₂O. The introduction of defect structures could disrupt the hydrogen bonds and alters the adsorption behavior of OH groups, leading to improved H₂O splitting kinetics. Additionally, the incorporation of the organic molecule DATZ facilitates the conversion of *CO intermediates to CO, enhancing the overall CO₂ conversion rate. The modified catalyst g-CN-DZ625 exhibits enhanced CO₂ capture ability. Meanwhile, N defect serves as an active site for CH₄ production. Experimental results show that g-CN-DZ625 demonstrates CO and CH₄ evolution rate of 11.86 and 4.45 μmolg^-1h⁻¹, respectively, that is 3.62 and 18.54 times higher than that of g-CN-625. The reaction mechanism was further elucidated through in-situ FTIR and DFT simulations.