High sensitivity room temperature sulfur dioxide sensor based on conductive poly(p-phenylene)/ZSM-5 nanocomposite

Recently, there has been growing interests in the development of composite materials as the new alternative gas sensing materials for replacing metal oxide based sensors which require the elevated operating temperature. Herein, we reported the fabrication and testing of new sensing composite materials based on the conductive poly(p-phenylene) (PPP) nanoparticle and zeolites for sulfur dioxide (SO2) detection at room temperature under the effects of doping, zeolite type, zeolite content, SO2 concentration as well as interferences and humidity. The relative electrical conductivity response depended critically on the doping agent type, doping ratio, and doping temperature. The addition of porous zeolites into the doped-PPP (dPPP) matrix induced the improvement in selectivity and sensing performances towards SO2 as it promoted more surface area for SO2 adsorption and its new synergistic effect with the conductive dPPP, related to the additional conductive polymer doping from the dissolution of the SO2 in intrazeolitic water as identified and reported here. Among all materials, the dPPP/ZSM-5 composite with perchloric acid (HClO4) as the doping agent, the doping ratio of 50:1, the doping temperature of 70 degrees C, and the zeolite content of 30% exhibited the highest relative response of 25.42 towards 500 mg L-1 SO2 with good repeatability. This composite provided the SO 2 sensitivity of 0.0483 L mg(-1) with R-2 of 0.9927 and the limit of detection (LOD) of 5 mg L-1 as determined from the electrical conductivity signal to noise ratio. The present sensing material is a potential candidate in the practical detection of SO2 at room temperature. (C) 2020 Elsevier B.V. All rights reserved.