Fabrication and H2S gas sensitive performance of NiO ultrathin film encapsulated VO2(A) nanowire core-shell heterojunction structure

Abstract High performance hydrogen sulfide (H 2 S) gas sensor is highly desired to develop for the harmfulness of H 2 S to human’s health. In this work, a NiO/VO 2 (A) nanowire core-shell heterojunction is constructed through chemical precipitation and annealing to improve the sensitivity to H 2 S. The influence of precursor molar ratios on the composition, morphology, and gas-sensing performance of the core-shell heterojunction structure was investigated. The NiO/VO 2 (A) nanowire core-shell heterojunction based sensor exhibits high sensitivity when the precursor molar ratio is 1:0.5. The gas response value is reached up to 11.57 to 1 ppm H 2 S gas at 100°C. And the gas sensor also shows excellent response and recovery characteristics. The high sensing performance is related to the heterojunction between VO 2 (A) and ultrathin NiO film and the catalytic activity of NiO, which can enhance the chemical adsorption of oxygen on the surface of the heterojunction structure. The results suggest that VO 2 (A) nanowires core-shell nanostructure have great potential for H 2 S gas detection.