Propose of high performance resistive type H₂S and CO₂ gas sensing response of reduced graphene oxide/titanium oxide (rGO/TiO₂) hybrid sensors

Few studies have investigated the electrical and gas sensing properties of reduced graphene oxide/titanium dioxide (rGO/TiO₂) composite thin films by spray pyrolysis technique. In this work, we report the synthesis and systematic investigation of structural, morphological and gas sensing properties of rGO-loaded TiO₂ nanocomposite thin films. The XRD and AFM results suggest that both pure and rGO/TiO₂ nanocomposite showed crystalline with tetragonal anatase phase and individual spherical shaped nanoparticles with average diameter of around 20–30 nm was observed. rGO/TiO₂ nanocomposite showed high surface area (112 m²/g) and larger pores (11.2 nm) than bare TiO₂ (89 m²/g; 32.3 nm). This huge surface area can beneficial for enhancing the gas sensing performance. Resistive type gas sensor set up was constructed and studied the sensing responses towards H₂S and CO₂ gases. The results suggest that the rGO/TiO₂ nanocomposite sensor showed high sensitivity (92%), stability (only loss 3.5%), fast response (30 s) and recovery time (25 s) towards CO₂ gas. The improved gas sensing mechanism of the proposed sensor was discussed in detail.