Selective H₂S sensing without external heat by a synergy effect in self-heated CuO-functionalized SnO₂-ZnO core-shell nanowires

Future gas sensors require minimal power consumption to enable their integration into portable electronics such as smart mobile phones. We developed H₂S gas sensors based on a self-heating effect using metal oxide nanowires (NWs). We fabricated bare SnO₂ NWs, CuO functionalized SnO₂ NWs, and a CuO functionalized SnO₂-ZnO core-shell (C–S) NW sensor, and tested their sensor response towards H₂S gas by applying different external voltages at room temperature. It was found that the CuO functionalized SnO₂-ZnO C-S NW gas sensor had higher response to H₂S gas relative to other tested sensors due to higher self-heating effect, formation of heterojunctions, phase transformation, and spillover effects of CuO nanoparticles. Without external heat, the selective H₂S detection obtained in this work demonstrates the possibility of embedding low power consumption gas sensors in portable devices for detection of H₂S as a biomarker for early diagnosis of diseases.