NiO nanosheet/TiO2 nanorod-constructed p-n heterostructures for improved photocatalytic activity

NiO nanosheet/acid-corroded TiO2 nanorod (A-TiO2 nanorod) heterostructures with high photocatalytic activity were successfully fabricated via a facile and low-cost hydrothermal route. The as-prepared heterostructures featured NiO nanosheets with uniformly assembled A-TiO2 nanorods and a rough surface. The morphology, structure, and photoelectric properties of the pristine NiO nanosheets and TiO2-based nanomaterials were characterized in detail, and results revealed that secondary NiO nanosheets were successfully grown on TiO2 nanorod substrates to achieve a p-n heterostructure between the cubic structure NiO and the TiO2 anatase phase. In comparison with P25, NiO nanosheets, TiO2 nanorods, and A-TiO2 nanorods, the proposed heterostructures exhibited markedly enhanced photocatalytic activity for the degradation of methyl orange under UV light irradiation. Specifically, the NiO nanosheet/A-TiO2 nanorod heterostructures exhibited the best photocatalytic activity, achieving 100% photocatalytic efficiency within 20 min. The observed enhancement in photocatalytic activity was attributed to the synergetic contributions of p-n heterostructures and the large specific surface area of the catalyst, which may improve the separation of photogenerated electron-hole pairs and prolong the lifetime of charge carriers. The heterostructures could be easily recycled without observable decreases in photocatalytic activity because of their one-dimensional nanostructural property. (C) 2015 Elsevier B.V. All rights reserved.