Facile synthesis of metal-organic framework-derived ZnO/CuO nanocomposites for highly sensitive and selective H2S gas sensing

ZnO/CuO nanocomposites were derived from a metal-organic framework (MOF) using a simple precipitation method. The mesoporous nature, crystallinity, and fine particle size of the synthesized ZnO/CuO nanocomposites varied with CuO amounts, affecting the gas sensing ability of different gases (H2S, CO, C6H6, and C7H8 gases). It was found that the ZnO/CuO (40 mol%) gas sensor showed the highest sensing capacity in terms of response, selectivity, and repeatability on low concentrations of H2S gas (10 ppm). The strong sensing performance, short response time (58 s) and recovery time (273 s) were explained in terms of the texture coefficients (phase percentage, crystal size, and crystallinity) of the ZnO and CuO phase compositions, resulting in the formation of a high number of p-n junctions and quantum confinement effects in the nanocomposite, as well as the lower binding energy of H2S. The fast sensing ability of a low H2S concentration highlights the practical importance of these MOF-derived ZnO/CuO nanocomposites.