Photocatalytic Reduction of CO2 by TiO2 Nanotubes

Abstract

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.