Enhanced photoelectrochemical performance of NiO-doped TiO₂ nanotubes prepared by an impregnation–calcination method

Abstract

To improve the photocatalytic activity of TiO2, a series of NiO–TiO2 nanotubes (NTbs) is prepared by impregnating TiO2 nanotubes in a solution of NiCl2·6H2O at different concentrations. Self-organized TiO2 nanotubes are prepared by a two-step anodization process. Scanning electron microscopy images show that large particle agglomerates are formed for higher precursor concentrations, and X-ray energy-dispersive spectroscopy results indicate that the atomic percentages of Ni in the NiO–TiO2 NTbs prepared with precursor concentrations of 100 and 300 mM are 1.95% and 4.23%, respectively. Electronic lifetime measurements show that the recombination rate of photogenerated electron–hole pairs is lower for NiO–TiO2 NTbs compared to that of TiO2. Specifically, the recombination rate of the sample prepared at 50 mM is the lowest, which is associated with the longest electron lifetime. Compared to unmodified TiO2 nanotubes, NiO–TiO2 NTbs exhibit improved results for the photocatalytic degradation of rhodamine B.

Fabrication of Cu2O-loaded TiO2 nanotubes with heterojunctions via an electrochemical method: enhanced photocatalytic activity

“…5), which may due to the adsorption desorption reaction mechanism during the photodegradation process on the Cu 2 O–TiO 2 NT surface, which is consistent with our previous work. 1,27 Fig. 6(b) shows the incident photon-to-electron conversion efficiency (IPCE) under monochromatic illumination, which was calculated using the following formula:where j p is the photocurrent density, P is the incident light density per unit area, and λ is the incident light wavelength.…”

“…23–26 Wang et al deposited NiO nanoparticles (NPs) on TiO 2 NTs using a direct impregnation–calcination method and achieved improved photocatalytic performance. 27 Liu et al designed and prepared a novel TiO 2 /MoC–Mo 2 C@C heterostructure via a calcination method and realized enhanced photocatalytic activity in water splitting, thus achieving a high H 2 generation rate of 918 μmol h −1 g −1 . 28 Further, Li et al reported an improved H 2 production rate of 24.83 μmol h −1 g −1 for a TiO 2 catalyst doped with Cu 2 O.…”

TiO2 Nanotubes Decorated with Mo2C for Enhanced Photoelectrochemical Water-Splitting Properties

“…However, TiO 2 can only be stimulated by UV light, which accounts for only 3–5% of solar energy radiation, because of its large band gap, further causing quick recombination of photoinduced electron-hole pairs as well as inefficient charge carrier separation [ 11 ]. Therefore, various methods have been used to improve the PEC performance and photocatalytic activity of TiO 2 , including morphology modification [ 12 , 13 , 14 ], synthesis of composite heterojunctions with other materials [ 15 ], ion doping [ 16 , 17 ], facet engineering [ 18 ], and cocatalyst addition [ 19 ].…”