Photocatalytic Reduction of CO₂ by TiO₂ Nanotubes

Continuously increasing atmospheric concentrations of CO2 have given rise to great concerns about climate change. Photocatalytic reduction of CO2 to chemicals by solar energy is considered a green and sustainable process. Interactions between CO2 molecules and photocatalysts surfaces are the key factors that affect photocatalytic reduction efficiency. Thus, a better understanding of their reactive species on the TiO2 nanotube (TNT) surfaces by in situ FTIR spectroscopy was studied in the present work. The FTIR absorbance features at 1303[Formula: see text]cm[Formula: see text] and 1393[Formula: see text]cm[Formula: see text] were associated with carbonate species, e.g., bidentate carbonate on the TNT. Complete desorption of CO2 from the TNT occurred at [Formula: see text][Formula: see text]K. The carboxylate species that were adsorbed on the TNT may conduct the surface reactions enhanced by UV–Vis light to yield low carbon chemicals.