Hierarchical WO₃-NiO microflower for high sensitivity detection of SF₆ decomposition byproduct H₂S

In this work, hierarchical WO₃-NiO microflowers have been designed and prepared through a controllable hydrothermal route for high sensitivity detection of H₂S produced by SF₆ decomposition. The hierarchical flower-like nanostructures assembled with numerous nanosheets were influenced by the introduction of WO₃, which is regarded as a significant strategy for improving the gas sensing properties. The synthesized nanostructures were tested by various characterization to investigate the different microstructures of the nanocomposites. The H₂S sensing performances of the sensors fabricated with these flower-like nanostructures were measured, which indicated that 3.0 at% WO₃-NiO microflower based sensor possessed excellent properties such as higher gas responses and more prominent repeatability compared with those of other fabricated sensors. The enhanced performances might be mainly ascribed to the creation of the heterojunction at n-type WO₃ and p-type NiO interface, which caused the improvement of the potential barrier and depletion layer. In addition, the larger specific surface area of flower-like nanostructures also possessed abundant sites for surface reaction.