Nickel-enhanced electrochemical activities of shape-tailored TiO2{001} nanocrystals for water treatment: A combined experimental and DFT studies

Abstract

Understanding the reaction mechanism at the solid/liquid interface is necessary to improve the catalytic activity of electrode materials for water treatment. In this study, the photoelectrocatalytic degradation of rhodamine B (RhB) and phenol in water was studied using undoped and Ni-doped TiO2 with {001} facets (TiO2{001}). Under visible light irradiation, Ni-doped TiO2 electrodes exhibited higher contamination removal efficiency than undoped ones. Photoluminescence detection and density functional theory calculations revealed that the Ni-doped TiO2 provides a better hydroxyl radical yield and adsorption capacity than the undoped TiO2, which could be a major reason for the improvement of the catalytic activity of Ni-doped TiO2. The diffuse reflectance spectroscopy data showed that introducing the Ni2+ ions into TiO2 can shift the absorption edge towards the visible light region, which also contributes to the excellent photoelectrocatalytic performance. This work provides a strategy for improving the electrochemical performance of TiO2 and an in-depth understanding of the doping and catalytic mechanism of Ni2+ ions.