Battery-operated resistive sensor based on electrochemically exfoliated pencil graphite core for room temperature detection of LPG

Abstract

The present paper illustrates a description on material synthesis, sensor fabrication and electronic prototyping of a cost effective, reusable, stable and highly sensitive and selective device for the sensing and quantification of trace concentrations of liquefied petroleum gas (LPG) in ambient conditions. Conductive colloidal solution of graphene synthesized via electrochemical exfoliation of 9B pencil graphite core was used for sensing LPG at ppm levels in air. In comparison to other metal oxide semiconducting (MOS) materials, electrochemically exfoliated graphene is very well recognized owing to its very economic prices and abundant availability of its raw material i.e. graphite, ease of fabrication and simple modification techniques. A self-assembled network of exfoliated graphene successfully fabricated on flexible polymer substrate exhibited appreciably high sensitivity to inflammable LPG. The principal of operation of the present resistive LPG sensor relies on the variation in the electrical resistance of the self-embedded exfoliated graphene network on its exposure to the gaseous analyte i.e. LPG in a two-pole format. The degree of variation in electrical resistance of the sensitive film depends on the concentration of the LPG to which it is exposed. On the basis of this fact qualitative as well as quantitative detection of the LPG with sensor response of 24.5 % and response time of 18 s at sensing limit as low as 50 parts-per-million (ppm) is achieved. Experimental investigations unveiled a competent LPG sensor which can sense and compute LPG leakage with prolonged high constancy and reproducibility.