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

Abstract

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 20min. 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.