HMDSO/ZnO-Graphene Heterostructure Coated Quartz Crystal Microbalance Transducer for VOCs Sensing

Accurate, reliable and fast, detection of different harmful volatile organic compounds (VOCs) is crucial criterion for medical, industrial, agricultural and environmental applications. To address the issue, in this study, porous HMDSO/ZnO-graphene heterostructure has been used as a sensitive layer. The thin HMDSO and ZnO-graphene nanocomposite layers have been elaborated on quartz crystal microbalance (QCM) transducer by plasma enhanced chemical vapor deposition (PECVD) and spray pyrolysis technique, respectively. The synthesized heterostructure was characterized by Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). The sensing performance of the coated QCM-based sensor was evaluated by expositing it to various concentrations of organic molecules. The coated QCM sensor demonstrated high sensitivity values of 1.26, 1.05, 1.58 and 0.90 Hz/ppm and low detection limit of 2.38, 2.58, 1.90 and 3.33 for toluene, ethanol, benzene and methanol, respectively. The sensing performance of the elaborated sensor correlates well its chemical and morphological properties. The observed results demonstrate the successful strategy of retaining the excellent property of graphene (high specific surface area) with plasma surface activation to improve the active sites for gas absorption.