Green Synthesis of Reduced Graphene Oxide for Gas Sensors: Real-Time Monitoring of Volatile Organic Compounds

Graphene oxide (GO) has gained significant attention in recent years due to its exceptional properties and wide range of applications. This study investigates the development of gas sensors based on reduced graphene oxide (rGO) for effective real-time monitoring of gas concentrations. The GO was produced using a modified Hummers’ method and then reduced using tea leaf extracts at different concentrations. The structure of rGO was confirmed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Raman spectroscopy. Ultraviolet (UV)–visible (Vis) spectroscopy analysis revealed a decrease in the bandgap of rGO with increasing concentrations of tea leaf extract. The gas sensors fabricated with the synthesized rGO were tested with methanol and ethanol, two common volatile organic compounds, demonstrating a fast response and recovery time. In addition, an analog front-end circuit was developed for the sensor exhibiting the highest sensitivity, enabling real-time monitoring of gas concentrations. These results suggest that rGO, reduced using green synthesis methods, holds significant promise for high-performance gas-sensing applications.