Photo-electrochemical reduction of carbon dioxide on the self-organized TiO₂ nanotube layers

Photo-electrochemical reduction of carbon dioxide on the porous films dispersed with self-organized TiO₂ nanotubes has been investigated in this work. The porous films were prepared by anodizing a titanium sheet in the electrolyte containing fluoride. Post annealing at 450 °C for 1 h, the crystal of the film turned from amorphous to anatase. The film was dipped in 1 M nitrate solution of Ag(I), Cu(II) and Fe(III), respectively, dried and irradiated by UV-light to load different impurity. Electrochemical tests including cyclic voltammetry (CV), potentiostatic reduction and electrochemical impedance spectroscopy (EIS) were conducted to estimate the catalytic activity of the films. The catalytic activity is higher for the films after compared with the as-anodized films. The catalytic activity of the porous film was enhanced with loading different impurities. The activity increases in the order: load-free < Ag-loaded < Cu-loaded < Fe-loaded films.