UV Light Assisted NO₂Sensing by SnO₂/Graphene Oxide Composite

• Main Authors: Hashitha M. M. Munasinghe Arachchige, Nanda Gunawardhana, Dario Zappa, Elisabetta Comini
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: Proceedings
• Subjects: SnO₂; reduced graphene oxide; metal oxide gas sensors; Low temperature gas sensors; NO₂ Sensing; SnO₂ /rGO heterojunction; UV light irradiation
• Online Access: https://www.mdpi.com/2504-3900/2/13/787

Nitric oxide (NO₂) is one of the air pollutants that pose serious environmental concerns over the years. In this study, SnO₂ nanowires were synthesized by evaporation-condensation method and graphene oxide were synthesized using modified Hummers method for low temperature NO₂ detection. Drop cast method was used to transfer graphene oxide (GO), to form composite GO-metal oxide p-n junctions. With integration of reduce graphene oxide (rGO), the UV light absorption was enhanced. This metal oxide composite has shown a reversible response in detecting low concentrations of NO₂ under UV irradiation, with a working temperature range of 50–150 °C. Pure SnO₂ shows 20% response to NO₂ (4 ppm) in dark conditions, while the response increasesupto60%usingUVirradiationat50°C.Furthermore, SnO₂/rGOshowsa40%ofresponse in dark, while the response increases to 160% under UV light illumination. This composite exhibits excellent recovery and maintains the baseline under UV light at low temperatures, which effectively overcome the drawbacks of low recovery typically shown by metal oxide gas sensors at low temperature.