Enhanced photoelectrochemical properties of NiO nanoparticles-decorated TiO2 nanotube arrays for water splitting

Vertically oriented titanium dioxide nanotube arrays (TNTAs) decorated with NiO nanoparticles (NPs) were successfully fabricated using two-step electrochemical anodization. An ultrasound-assisted deposition method was used to homogeneously loading the NiO NPs into the TNTAs, resulting in a NiO/TNTAs junction electrode. X-ray diffraction reveals that the TNTAs and NiO/TNTAs showed anatase structures. Also, SEM images confirm that the nanotubes have a nominal length of 3.57 µm and approximately equal wall thickness and diameters; 55.51 nm and 17.64 nm, respectively. The NiO/TNTAs junction electrode exhibited high visible light photo-response that enhances the photoelectrochemical activity. Accordingly, the incident photon-to-current conversion efficiency of NiO/TNTAs was estimated to be 86.89% in comparison to the pure TNTAs whose efficiency was equal to 29.62%. In conclusion, the NiO/TNTAs junction fabricated by a simple, cost-effective, and applicable cell is a promising clean renewable source for the water-splitting applications.