CuO nanosheets for sensitive and selective determination of H₂S with high recovery ability

In this article, cupric oxide (CuO) leafletlike nanosheets have been synthesized by a facile, low-cost, and surfactant-free method, and they have further been successfully developed for sensitive and selective determination of hydrogen sulfide (H₂S) with high recovery ability. The experimental results have revealed that the sensitivity and recovery time of the present H₂S gas sensor are strongly dependent on the working temperature. The best H₂S sensing performance has been achieved with a low detection limit of 2 ppb and broad linear range from 30 ppb to 1.2 ppm. The gas sensor is reversible, with a quick response time of 4 s and a short recovery time of 9 s. In addition, negligible responses can be observed exposed to 100-fold concentrations of other gases which may exist in the atmosphere such as nitrogen (N₂), oxygen (O₂), nitric oxide (NO), cabon monoxide (CO), nitrogen dioxide (NO₂), hydrogen (H₂), and so on, indicating relatively high selectivity of the present H₂S sensor. The H₂S sensor based on the CuO nanosheets also shows strong recovery ability and long-term stability, probably due to the effective diffusion of gas toward the whole sensing surface, as well as the different mechanism of H ₂S gas sensor from those reported at CuO nanowires and CuO-SnO ₂ nanocomposites, where a layer of CuS or Cu₂S has formed on the CuO surface.