Synthesis and Enhanced H₂S Sensing Properties of V₂O₃-NiO Nanoflower Assembled by Porous Nanosheets

Constructing porous structure has proved to be an effective strategy to improve the gas sensing properties of metal oxide semiconducting materials. In this work, high-performance hydrogen sulfide (H2S) gas sensing material with porous structure were synthesized by growing nickel oxide (NiO) on vanadium trioxide (V2O3) seeds. Morphology and structure characterizations reveal that the novel three-dimensional (3D) nanoflowers are formed by self-assembling two-dimensional (2D) porous nanosheets with high surface area and abundant active sites. Compared with pristine NiO, the sensing performance of V2O3-NiO (VN8, VN7, VN6) with different ratios of V3+: Ni2+ is enhanced due to their porous structure. Among them, VN7 sensor shows excellent sensing properties at 200 °C. The response to 500 ppb H2S can reach 65, which increases as high as 2.2 times compared with the pristine NiO sensor. The response time to 500 ppb H2S is further decreased from 13 s of the pristine NiO sensors to 8 s of VN7 sensor. The VN7 sensor also shows a wide linear range from 20 ppb to 500 ppb, high selectivity, good repeatability, long-term stability, moisture resistance and low detection limit (20 ppb), indicating its potential candidate for ppb-level H2S detection in complex environment of industrial mine.