Design and fabrication of zinc oxide-graphene nanocomposite for gas sensing applications.

[Display omitted] • Design principles of ZnO-graphene based gas sensors were investigated using density functional theory (DFT) calculations. • ZnO/graphene nanocomposites with varying graphene contents were synthesized by chemical method. • The hybrid structure exhibited the high gas response to ethanol gas, which was two-fold of the pristine graphene at the operating temperature. • • Enhanced response and selectivity to ethanol gas were explained. Gas sensing devices are essential in many applications and are widely developed to detect exhaust gases and air quality rapidly and accurately. However, there is still an urgent demand to achieve the sensing material and state-of-the-art sensor device. This work combines the theoretical and experimental studies to design and fabricate a hybrid zinc oxide (ZnO)/graphene to further tailor the materials for better performance than the individual materials. The first-principles calculations were performed to gain fundamental understandings of the gas response of the different hybrid structures. Then, we constructed the different nanocomposite models to include the graphene decorated with ZnO nanoclusters (Zn 12 O 12 /graphene), a hybrid ZnO/graphene layers, compared with bare ZnO and graphene layers. The best candidate matrix, Zn 12 O 12 /graphene, exhibiting excellent gas sensing properties, was selected for chemical synthesis using the reliable and straightforward technique. Hybrid nanocomposites were formed, varying the graphene concentrations in ZnO from 1 to 10 wt%, confirmed by SEM and XRD. The nanohybrid with 5 wt% graphene mixture showed a high gas response of 54.30 upon the ethanol gas of 2,000 ppm, which was more responsive than the graphene or ZnO alone. The proposed study can lead to the design and fabrication of highly sensitive ethanol gas sensors. [ABSTRACT FROM AUTHOR]