Hydrothermal Synthesis of SnO(2) Nanoneedle-Anchored NiO Microsphere and its Gas Sensing Performances

In this study, we reported a successful synthesis of a nanocomposite based on SnO(2) nanoneedles anchored to NiO microsphere by a simple two-step hydrothermal route. The results show that the SnO(2)/NiO nanocomposite-based sensor exhibits more prominent performances than the pristine NiO microsphere to NO(2) such as larger responses and more outstanding repeatability. The improved properties are mainly attributed to the p–n heterojunctions formed at the SnO(2)–NiO interface, leading to the change of potential barrier height and the enlargement of the depletion layer. Besides, the novel and unique nanostructure provides large and effective areas for the surface reaction. In addition, a plausible growth mechanism and the enhanced sensing mechanism were proposed to further discuss the special nanostructure which will benefit the exploration of high-performance sensors.