Reduced Graphene Oxide@Bimodal TiO2 Nanocomposites as an Efficacious Console for Room Temperature n-Butanol Gas Sensing

Abstract

Metal oxide nanomaterials possess an exceptional physical and chemical behavior apposite for gas-sensing applications. Among them, titanium dioxide (TiO₂) is a promising, robust, and economical material, and when paired with two-dimensional (2D) materials such as reduced graphene oxide (rGO), the resultant composite system is promoted to an interesting gas-sensing candidate. Properties of rGO- and TiO₂-based nanocomposites depend on the size and shape of TiO₂ nanoparticles and the weight percentage (wt %) ratio of rGO/TiO₂. Herein, the preparation of rGO@bimodal TiO₂ nanocomposites (hereafter referred to as G@TiO₂) by the conventional hydrothermal method having different wt % (1, 2.5, 5, and 10) of rGO with bimodal TiO₂ nanoparticles is reported. Structural, optical, morphological, and microstructural characterizations of the prepared nanocomposites revealed the generation of elongated submicron particles and nanorods of bimodal TiO₂ in the G@TiO₂ samples. The gas sensors based on the prepared materials were fabricated to evaluate their gas-sensing properties. The comparative analysis illustrated that the sensor based on 2.5%G@TiO₂ presented the highest sensitivity and selectivity to n-butanol at room temperature (25 °C). Furthermore, supplemental investigation on n-butanol adsorption properties of all sensors was carried out using a scanning Kelvin probe (SKP) technique, which further corroborated the exceptional n-butanol adsorption (>2 times) for the 2.5%G@TiO₂ surface at room temperature.