Synergistic effects of oxygen vacancies and mesoporous structures in amorphous C@TiO2 for photocatalytic CO2 reduction.

ABSTRACT

In this study, the theoretical calculations proves that the combination of oxygen vacancy and amorphous carbon films in TiO2 (VO-CT) can effectively reduce the energy bandgap and work function. The minimum Gibbs free energies required for the CO2RR reaction of VO-CT are 0.20 eV, which is lower than pure TiO2. The amorphous c@TiO2 nanomaterials with oxygen vacancy and mesoporous structures (VO-MCT) are prepared with the P123 surfactant as the template and oxalic acid as an inducer. The electron paramagnetic resonance indicates the presence of abundant oxygen vacancy defects in the samples. UV-vis spectra indicate that the mesoporous structure enhances light absorption capacity. The photocatalytic CO2 reduction tests show that the highest conversion rates for CH4 and CO of VO-MCT are 14 µmol g-1 h-1 and 10.66 µmol g-1 h-1, respectively. The electron consumption rate of VO-MCT is 12.43 times higher than that of commercial TiO2 (P200).