Ultra-sensitive IDE-based ammonia sensor fabricated using green synthesized graphene nanoplatelets and a TiO2 based composite

Abstract

The development of a reliable, sensitive, and economical gas sensor is crucial for effective environmental monitoring. In this study, we present the development of an interdigitated electrode (IDE) based graphene nanoplatelet (GnP) and GnP-TiO₂ composite NH₃ gas sensor operated at room temperature. Firstly, for the synthesis of GnPs, tea extract was used as a green alternative without the use of organic solvents using a kitchen mixer, whereas TiO₂ and GnP-TiO₂ were prepared via a simple hydrothermal process. An IDE-based chemiresistive sensor of GnPs and GnP-TiO₂ was tested for NH₃ detection over a wide concentration range of 100 ppb to 100 ppm at room temperature. The GnP-TiO₂ composite exhibited a response nearly eight times higher than that of the GnP sensor at 100 ppm NH₃. Additionally, the GnP sensor exhibited response and recovery times of 249 and 107 s, respectively, whereas the GnP-TiO₂ composite achieved 15 and 30 s, corresponding to an ∼17 fold faster response time and ∼3.5 fold quicker recovery at 100 ppb NH₃. Overall, this study advocates the applicability of a grown GnP-TiO₂ based composite for NH₃ sensing application in ppb level concentration.