Ammonia Gas Detection by Tannic Acid Functionalized and Reduced Graphene Oxide at Room Temperature

Reduced graphene oxide (rGO) based chemiresistor gas sensor has received much attention in gas sensing for high sensitivity, room temperature operation, and reversible. Here, for the first time, we present a promising chemiresistor for ammonia gas detection based on tannic acid (TA) functionalized and reduced graphene oxide (rGO(TA functionalized)). Green reductant of TA plays a major role in both reducing process and enhancing the gas sensing properties of rGO(TA functionalized). Our results show rGO(TA functionalized) only selective to ammonia with excellent respond, recovery, respond time, and recovery times. rGO(TA) (functionalized) electrical resistance decreases upon exposure to NH3 where we postulated that it is due to n-doping by TA and charge transfer between rGO(TA functionalized) and NH3 through hydrogen bonding. Furthermore, rGO(TA functionalized) hinders the needs for stimulus for both recovery and respond. The combination of greener sensing material and simplicity in overall sensor design provides a new sight for green reductant approach of rGO based chemiresistor gas sensor.