Dimensional Engineering of 1D/2D Synergistic TiO2 Nanostructures for High-Efficiency Photocatalytic CO2 Reduction

Alongside the gradual progress of industrialization and the continuous development of human society, the problems of environmental pollution and energy crisis have become increasingly prominent. Semiconductor photocatalysis is a promising solution to these challenges. The photocatalytic reduction of CO2by TiO2to produce carbon monoxide and methane is a process which has been identified as a means of developing clean energy. In this paper, two-dimensional TiO2(2D-TiO2) was synthesized via a one-step solvothermal method, and one-dimensional TiO2(1D-TiO2) was obtained through a hydrothermal process. Their photocatalytic CO2reduction performances were systematically investigated. The results show that 2D-TiO2exhibits superior catalytic activity compared to 1D-TiO2, which can be attributed to its lamellar structure, larger specific surface area, and improved hydrophilicity, providing more active sites and faster reaction kinetics. To further reveal the reaction mechanism, density functional theory (DFT) calculations were carried out using VASP with the GGA–PBE functional, PAW potentials, and a plane-wave cutoff energy of 520 eV. A 3 × 3 × 1 Monkhorst–Pack grid was used for Brillouin zone integration, and all possible adsorption configurations of CO2*, COOH*, and CO* intermediates on the 2D-TiO2surface were evaluated. The results confirm that 2D-TiO2stabilizes key intermediates more effectively, thereby lowering the energy barrier and facilitating CO2reduction. These findings demonstrate that structural modulation of TiO2significantly influences its photocatalytic performance and highlight the great potential of 2D-TiO2for efficient CO2conversion and clean energy applications.