An ultrasound-assisted deposition of NiO nanoparticles on TiO2 nanotube arrays for enhanced photocatalytic activity

Abstract

An ultrasound-assisted deposition technique was adopted to construct NiO nanoparticles on TiO₂ nanotube arrays (NiO–TiO₂ NTAs) which were prepared by three-step electrochemical anodization in an ethylene glycol system. The NiO nanoparticles were found to deposit on the surface of the highly oriented TiO₂ nanotubes. NiO–TiO₂ NTAs exhibited improved photochemical capability under UV irradiation. Compared with TiO₂ NTAs, a more than 2.56-fold enhancement in photocurrent response was achieved using the NiO–TiO₂ NTAs. The maximum incident photon to charge carrier generation efficiency (IPCE) values of NiO–TiO₂ NTAs and TiO₂ NTAs were 83.5% and 22.2%, respectively. The photocatalytic activities of NiO–TiO₂ NTAs were evaluated by the photodegradation of methylene blue (MB) aqueous solution. The kinetic constant of photocatalytic degradation of MB using NiO–TiO₂ NTAs prepared by ultrasonic deposition for 1.0 h was 1.9 times higher than that using TiO₂ NTAs. The enhanced photocurrent response and photocatalytic activity with NiO–TiO₂ NTAs were attributed to the formation of the NiO–TiO₂ p–n junctions.