A highly sensitive room temperature liquefied petroleum gas (LPG) sensor with fast response based on a titanium dioxide (TiO2)–reduced graphene oxide (r-GO) composite

Abstract

Liquefied petroleum gas (LPG), although extremely important in terms of both domestic and industrial contexts, can be potentially hazardous due to accidental leakage caused by process failure or human error. Designing sensors for the efficient detection of LPG is thus extremely crucial. In this paper, we have demonstrated the LPG sensing properties of a reduced graphene oxide (r-GO)–TiO₂ based composite material. TiO₂ was synthesized via a simple co-precipitation method and the compositing process with r-GO was carried out in situ. The samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), etc. As an LPG sensor, the composite showed excellent response with its resistance changing almost 10 times under exposure to 2.5 vol% LPG. A fast response time of 23 s and recovery time of 20 s were observed. The sensor also showed excellent stability and selectivity. The entire sensing response was evaluated at room temperature, suggesting the commercial viability of the TiO₂–rGO LPG sensor.