Enhanced Photoelectrochemical Performance of Co/TiO₂Nanotubes Prepared by Electrodeposition

Abstract

TiO2 nanotube arrays (NTbs) have been widely used in the field of photocatalysis due to their large surface area, good controllability and superior electron transport properties. However, due to its wide bandgap (3.2[Formula: see text]eV), pure TiO2 can only be excited by ultraviolet light ([Formula: see text][Formula: see text]nm), leading to low utilization of solar energy. Second, the high recombination rate of the photogenerated electrons and holes ([Formula: see text]/[Formula: see text] pair also reduces the quantum efficiency of TiO2. In order to realize the efficient photocatalytic activity of TiO2 nanomaterials, it is necessary to design the TiO2 nanomaterials to optimize the utilization of the solar spectrum. In this study, TiO2 NTbs were obtained by the anodizing method using titanium foil, and a series of Co/TiO2 NTbs were prepared by electrochemical deposition. The effects of the deposition voltage on the physical and photocatalytic properties of the Co/TiO2 NTbs were investigated. Results found that the Co/TiO2 NTbs had the highest photocurrent density 0.7[Formula: see text]mA/cm2 at an electrodeposition time of 60[Formula: see text]s and a voltage of 1[Formula: see text]V, and the photoelectric conversion efficiency was 15.85%, which was approximately 2.8 times that of the pure TiO2 NTbs. The degradation rate of Rhodamine B of the Co/TiO2 NTbs in 120[Formula: see text]min was 76.3%, whereas that of the pure TiO2 NTbs was only 48.7%. The forbidden bandwidth of the Co/TiO2 NTbs was reduced to 3.02[Formula: see text]eV, whereas that of the pure TiO2 NTbs was 3.2[Formula: see text]eV.