Ammonia Gas Sensing Behavior of Hybridization between Reduced Graphene Oxide and Gold Nanoparticles

Abstract

Stack and composite are the two ways of hybridization between gold nanoparticles (AuNPs) and reduced graphene oxide (rGO) which have been fabricated and tested the ability to detect NH3 gas at room temperature. The device based on the rGO-AuNP composite structure exhibited the highest response and the fastest response and recovery time compared to stack and bare rGO. The red shift of a resonant peak in the absorption spectra and the negative shift in the binding energy of 4f5/2 peak indicated that the remarkable NH3 gas-sensing properties of this composite are mainly attributed to a chemical bonding formed between AuNPs and rGO at the defective sites. This type of interaction facilitates the electron transfer from the defect states to the AuNP surface wherein it easily reacts with the oxygen molecules in the atmosphere to create oxygen absorbents. Consequently, NH3 not only reacts with sp3-hybridized atoms but also reacts primarily with oxygen absorbents on the surface of AuNPs, resulting in a better sensing behavior of composite samples.

Tunning the Gas Sensing Properties of rGO with In2O3 Nanoparticles

“…Consequently, the gas-sensing properties of rGO should be strongly dependent on the reduction process and the remaining oxygenated groups on its surface. Some recent strategies to tailor and improve these materials' performance as gassensitive layers are based on combining rGO with other nanostructured materials such as metal nanoparticles [29,30], quantum dots [31,32], transition metal dichalcogenides [33][34][35][36], and semiconducting metal oxides (SMOx) nanoparticles [37]. Recent work on nanocomposites based on rGO-SMOx demonstrated that these materials should achieve highperformance at a low-temperature range (<150 • C).…”