Studies on NH3 gas sensing by zinc oxide nanowire-reduced graphene oxide nanocomposites

ZnO nanowire-reduced graphene oxide nanocomposites have been prepared and used to detect ammonia at room temperature successfully. The nanocomposites are synthesized through hybridization of ZnO nanowires and graphene oxide sheets, which have been produced in large scale through mechanical mixing and low-temperature thermal reduction process. The micro ammonia sensors based on the as prepared nanocomposites are subsequently constructed by dip-dropping method. The resultant device exhibits excellent response (19.2%) to NH3 at room temperature, which is much better than pure reduced graphene oxide based gas sensors. It is revealed that ZnO nanowires can provide pathways for electron transfer on reduced graphene oxide sheets, thus the ZnO nanowire-reduced graphene oxide nanocomposites based sensors show excellent overall sensing performance with high response, short response and recovery time, good stability and excellent selectivity. Moreover, the sensor has a very small size and low power consumption, which are critical for system integration and portable equipment. Our work can hold a great potential for realistic applications in ammonia detection fields. (C) 2017 Elsevier B.V. All rights reserved.