Hydrothermal synthesis of hierarchical WO3/NiO porous microsphere with enhanced gas sensing performances.

• The hierarchical WO 3 /NiO porous microsphere and rough microsphere were synthesized via hydrothermal process. • The gas sensor based on the porous microsphere shows more excellent performances to ethanol. • The possible mechanism involved in enhancing the gas sensing performances was discussed in detail. Two novel hierarchical WO 3 /NiO microspheres with porous and rough surface have been prepared through a simple one-stop hydrothermal method. Interestingly, it is a surprise that the introduction of different amounts of WO 3 plays a critical role in the growth and self-assembly of nanosheets and then the morphology of microsphere. Further gas sensing experiment demonstrates that the sensor based on porous microsphere possesses prominent performance towards 100 ppm ethanol at the optimal working temperature of 300 °C compared with that of rough microsphere. It is believed that the enhanced gas sensing properties benefit from the porous structure on the surface with abundant active sites and gas passages for sufficient gas adsorption and diffusion. [ABSTRACT FROM AUTHOR]