Metal-organic framework-derived ZnO decorated with CuO for ultra-high response and selectivity H2S gas sensor

Abstract

Fast response recovery time and high response value are very necessary indicators for H2S sensors in the past few years. As H2S is a toxic gas that has great threat to human life, research on H2S gas sensors has received widespread attention. In this work, H2S gas sensors with high response value, excellent selectivity and fast response/recovery time were prepared by liquid phase synthesis method. Firstly, ZIF-8 (zeolite imidazolate framework-8) metal-organic framework derived ZnO was synthesized. Then high performance CuO/ZnO sensing materials modified with different amounts of CuO were synthesized using ZnO as the pristine material and CuO as the sensitizing material. Furthermore, the gas sensing test was conducted and the results show that the synthesized CuO/ZnO has significantly enhanced sensing performance to H2S. The highest response to 10 ppm H2S is 941 at a relatively low working temperature of 175 °C, which is 80 times higher than that of ZIF-8 derived ZnO. Moreover, the sensor based on CuO sensitized ZnO also showed excellent selectivity, fast response/recovery property and good moisture resistance. The enhanced gas sensing performance is mainly attributed to the formation of p-n heterojunction and the strong chemical affinity and catalytic performance of CuO for H2S.