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

Abstract

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.