Synthesis, characterization, and gas-sensitive properties of SnO/SnO2 core–shell homojunction by vapor-oxidate-solid process

Along with the rapid development of modern industry and the continuous improvement of environmental protection standards, it was imperative to detect harmful gases. In this study, the SnO/SnO 2 core–shell homojunction was successfully prepared by the vapor-oxidate-solid (VOS) method and a simple heating experimental device with Sn-bearing e-waste as raw material. The gradient oxidation of SnO was researched by detecting the crystal structure, micro-morphology and surface chemical state at different temperatures. The SnO/SnO 2 -based sensor was used for the gas sensitivity test of NO 2 . At 150 °C, high response value, response time and recovery time of SnO/SnO 2 homojunction to 50 ppm NO 2 were 421, 39 s and 27 s, respectively, which had better sensing performance compared with commercial SnO 2 . Moreover, the mechanism analysis indicated that homojunction and oxygen vacancies were important reasons for improving the gas-sensing performance of SnO/SnO 2 homojunction. It provided an effective strategy for recycling Sn resources and promoted the application prospect of SnO/SnO 2 homojunction in the NO 2 sensing field.