Enhancing low-temperature H₂S sensing performance of SnO₂ quantum wires <i>via</i> transition metal doping and oxygen vacancy engineering

Doping impurity atoms into metal oxide semiconductors plays a crucial role in modulating both their electronic and chemical properties at active sites. Tin oxide (SnO₂) quantum wires (QWs), with their large surface area and numerous exposed active sites, have shown significant potential as sensing materials for gas sensors. However, challenges such as unsatisfactory selectivity and detection limits (LODs) still hinder their performance. In this study, we explore the electronic interactions between transition metal atoms (V, Nb, or Ta) and sub-nm ultrathin SnO₂ QWs, while also introducing oxygen vacancies to enhance H₂S sensing performance. The resulting tailored electronic structures lower the energy barrier for gas molecule adsorption and electron transport, promoting the activation of oxygen and accelerating surface reaction kinetics with H₂S molecules. Notably, the Ta-doped SnO₂ QWs demonstrate significantly improved low-temperature H₂S sensing, with a real LOD reaching sub-ppb level, surpassing most reported metal oxide-based sensors. This work provides new insights into the development of high-performance gas sensors through the rational manipulation of electronic structures.