GO/Cu2O nanocomposite based QCM gas sensor for trimethylamine detection under low concentrations

Graphene oxide and cuprous oxide (GO/Cu2O) nanocomposite based quartz crystal microbalance (QCM) gas sensor via layer-by-layer self-assembly (LBLSA) method was developed for trimethylamine (TMA) gas sensing under concentrations of 5 ppm. The sensor response increased linearly with the concentration of TMA, which was consistent with the Saurebrey equation. It also had good sensitivity, reversibility, selectivity and stability in 60 days. The detection limit of 230 ppb was achieved which was the lowest detection levels among recently reported QCM gas sensor towards TMA under room temperature. The sensing mechanism of GO/Cu2O nano composite based QCM gas sensor towards TMA under low concentrations was proposed as follows: (1) an adsorption-desorption process via hydrogen bonding between the GO surface carboxyl groups and TMA molecules; (2) enhanced physical adsorption of TMA gas molecules via LBLSA method due to enlarged surface area and p-n junction of GO/Cu2O nanocomposite. This GO/Cu2O nanocomposite based QCM gas sensor may provide a foundation for the TMA gas sensors development in areas of environmental protection and food safety.