Review—Recent Advancements of ZnO/rGO Nanocomposites (NCs) for Electrochemical Gas Sensor Applications

Zinc oxide (ZnO)/rGO (reduced graphene oxide) composites have recently gained much interest in electrochemical gas sensor devices due to their fascinating electrochemical properties such as active surface sites, high surface area to volume ratios and high carrier large mobility. ZnO is a significant gas sensing material due to its excellent response towards oxidizing/reducing gases, easy preparation, and less toxicity. At the same time, graphene oxide and reduced graphene oxide-based sensors exhibited high surface area, and the presence of surface functional groups facilitated gas sensing properties. The synergistic effect of ZnO/rGO improved sensing properties and binding stability with macromolecules, thus making them potential candidates for the design of gas sensor devices. However, the fabrication and utilization of gas sensors operating at the low-temperature condition is still a significant hurdle. This review encompasses the recent advancements of ZnO/rGO nanostructures synthesis, studying nanocomposite interactions in various gas sensing applications. This study also proposes future outlooks on the ZnO-rGO gas sensors high selectivity and sensitivity for gas detection at low working temperature.