Mo-doped SnO2 nanotubes sensor with abundant oxygen vacancies for ethanol detection

This work describes a synthesizing method for Mo-doped SnO2 nanotubes (NTs) with uniform morphology by combining electrostatic spinning and air sintering. The method uses Mo ions to do substitutional doping of Sn ions in SnO2 to construct new lattice defects (such as oxygen vacancies), which provides more active sites for gas adsorption. Ethanol was taken as an example to study gas sensitivity characteristics of synthesized products. The analysis showed that 5 mol% of Mo-doped SnO2 nanotubes sensor exhibited the highest response (46.8) to 100 ppm ethanol at a lower optimum temperature (220 °C) and reduced the response/recovery time to 7/103 s. Also, it manifested excellent selectivity and long-term stability. The functionalized nanotubes structure and optimized parameters (oxygen vacancies concentration, metal vacancies defects, carrier concentration, catalytic sites, and base resistance increased) are the reasons for enhancing gas-sensing performance. This work provides direction that the optimal doping concentration of transition metal elements for metal-oxide NTs gas sensors can achieve the best sensing response.