Enhanced toluene gas-sensing properties of MEMS sensor based on Pt-loaded SnO2 nanoparticles

Rapid detection of low concentration toluene is highly desirable in environment monitoring, industrial processes, medical diagnosis, etc. In this study, we prepared Pt-loaded SnO2 monodispersed nanoparticles through hydrothermal method and assembled a sensor based on micro-electro-mechanical system (MEMS) to detect toluene. Compared with the pure SnO2, the 2.92 wt% Pt-loaded SnO2 sensor exhibits a 2.75 times higher gas sensitivity to toluene at about 330 & DEG;C. Meanwhile, the 2.92 wt% Pt-loaded SnO2 sensor also has a stable and good response to 100 ppb of toluene. Its theoretical detection limit is calculated as low as 12.6 ppb. Also, the sensor has a short response time of & SIM;10 s to different gas concentrations, as well as the excellent dynamic response-recovery characteristics, selectivity, and stability. The improved performance of Pt-loaded SnO2 sensor can be explained by the increase of oxygen vacancies and chemisorbed oxygen species. The electronic and chemical sensitization of Pt to SnO2-based sensor, together with small size and fast gas diffusion of the MEMS design ensured fast response and ultra-low toluene detection. This provides new ideas and decent prospect for developing miniaturized, low-power-consumption, and portable application of gas sensing devices.

Automated summary

In this study, Pt-loaded SnO2 monodispersed nanoparticles were prepared and a sensor based on micro-electro-mechanical system (MEMS) was assembled to detect toluene. The Pt-loaded SnO2 sensor showed significantly higher gas sensitivity to toluene and stable response to 100 ppb of toluene. It also demonstrated fast response time, excellent dynamic response-recovery characteristics, selectivity, and stability. The improved performance of the sensor can be attributed to the increase of oxygen vacancies and chemisorbed oxygen species, as well as the electronic and chemical sensitization of Pt.