CuO/WO3 hollow microsphere P-N heterojunction sensor for continuous cycle detection of H2S gas

Hydrogen sulfide (H2S) is an extremely flammable and toxic gas. In this work, we have synthesized WO3 and CuO/WO3 composites for H2S detection using a simple hydrothermal method. The morphology, structure, chemical composition, and gas-sensitive properties of the samples are comprehensively characterized. The results show that the WO3 structure comprises of hierarchical hollow microspheres self-assembled by nanoparticles, and the CuO/WO3 composite retains the hollow microspherical structure of the pure WO3. Furthermore, the gas sensing performance of the CuO/WO3 sensor is significantly improved compared with that of WO3, with a response value of 1297 for 10 ppm H2S at an optimum operating temperature of 70 celcius, which is nearly 103 times that of WO3 (12.5). It also exhibits a rapid response capability (13 s), lower detection limit (100 ppb), and excellent selectivity. In addition, the sensing mechanism of CuO/WO3 composites for H2S gas detection is analyzed in detail. The improved performance may be related to the morphological structure of the CuO/WO3 material and the formation of p-n heterojunction and CuS intermediates.