Metal-Organic frameworks-derived bamboo-like CuO/In2O3 Heterostructure for high-performance H2S gas sensor with Low operating temperature

Abstract

Hydrogen sulfide (H2S) sensors with excellent response and selectivity are in great demand to monitor its concentration changes in the real environment, especially at an ultra-trace level. This work presents a metal-organic framework (MOF)-derived metal oxide prepared via the solvothermal method and the developed sensors based on such materials exhibits enhanced gas-sensing performance. The bamboo-like CuO/In2O3 derived from Cu2+-impregnated CPP-3 were investigated through structural analyses, and it confirms that the n-type In2O3 and p-type CuO were successfully combined and heterojunctions were formed at CuO/In2O3 interfaces. The gas-sensing properties of CuO/In2O3 towards H2S were evaluated, and the sensor based on CuO/In2O3 with 3.5 wt% of Cu to CPP-3(In) is found to exhibit excellent H2S response (Rair/Rgas = 229.3–5 ppm), which are 8.5 times higher than that of with pristine In2O3. It also discloses low detection limits (200 ppb), low operating temperature (70 °C) and superior selectivity against other interfering gases. The gas sensing mechanism is thoroughly discussed and CuO/In2O3 could be considered as a novel and promising material for the practical application to selectively detect H2S at low operating temperature.