Synergetic regulation of interfacial electronic structure of Cu, N co-doped carbon modified TiO2 for efficient photocatalytic CO2 reduction

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TiO2 was a promising candidate material for CO2 photoreduction, but its development was greatly limited due to inherent defects such as high recombination rate of photogenerated charge carriers and limited number of active sites. In this study, a method involving chelation of metal ions with amino acids followed by high-temperature pyrolysis was employed to prepare Cu, N co-doped carbon-modified TiO2 composite materials, aiming to enhance the photocatalytic CO2 reduction performance of TiO2. The introduction of Cu, N co-doped carbon effectively improved the surface morphology of TiO2, increased the specific surface area and porosity, and enhanced the adsorption capacity of CO2. Simultaneously, the modification of TiO2 by Cu, N co-doped carbon optimized the electronic structure of catalysts, facilitating the separation and transfer of photogenerated electron-hole pairs, reducing charge carrier recombination, and thereby synergistically improving the thermodynamics and kinetics of CO2 reduction. Photocatalytic performance tests revealed that 10 % Cu-TiO2 exhibited the best CO2 reduction performance at a calcination temperature of 450 °C, with a CO production rate of up to 46 μmol·g−1·h−1, approximately 18 times that of pure TiO2. Density functional theory (DFT) calculations further confirmed that the introduction of Cu, N co-doped carbon reduced the Gibbs free energy of the CO2 reduction reaction, promoting the reaction. This study provides a simple, cost-effective strategy for developing efficient photocatalytic CO2 reduction materials.