CuO Nanosheets for Sensitive and Selective Determination of H₂S with High Recovery Ability

Abstract

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 H2S gas sensor from those reported at CuO nanowires and CuO−SnO2 nanocomposites, where a layer of CuS or Cu2S has formed on the CuO surface.