Abstract
A hybrid structure gas sensor of reduced graphene oxide (RGO) decorated graphene (RGO-Gr) is designed for ultra-low concentration ammonia detection. The resistance value of the RGO-Gr hybrid is the indicator of the ammonia concentration and controlled by effective charge transport from RGO to graphene after ammonia molecule adsorption. In this hybrid material, RGO is the adsorbing layer to catch ammonia molecules and graphene is the conductive layer to effectively enhance charge/electron transport. Compared to a RGO gas sensor, the signal-to-noise ratio (SNR) of the RGO-Gr is increased from 22 to 1008. Meanwhile, the response of the RGO-Gr gas sensor is better than that of either a pristine graphene or RGO gas sensor. It is found that the RGO reduction time is related to the content of functional groups that directly reflect on the gas sensing properties of the sensor. The RGO-Gr gas sensor with 10 min reduction time has the best gas sensing properties in this type of sensor. The highest sensitivity is 2.88% towards 0.5 ppm, and the ammonia gas detection limit is calculated to be 36 ppb.
Highlights
Ammonia gas is widely present in the surrounding environment
This paper proposes a new reduced graphene oxide (RGO)-Gr hybrid structure based on pristine chemical vapor deposition (CVD) graphene decorated with RGO to combine the advantages of both graphene and RGO, in order to obtain good gas sensitivity and low noise characteristics
Graphene on the interdigital electrode (IDE) is used as the conductive layer, and RGO decorated on the graphene is used as gas adsorption layer, which used as the conductive layer, and RGO decorated on the graphene is used as gas adsorption layer, forms the hybrid structure of the sensor
Summary
Ammonia gas is widely present in the surrounding environment. It is a colorless, irritating odor and highly toxic gas, the detection of ammonia is very important due to the potential threat to people’s health posed by ammonia [1,2]. The concentration of ammonia in human exhaled breath is approximately in the range of 50 parts per billion (ppb) to 5 parts per million (ppm) [4]. In order to improve previous medical testing methods, there is an urgency to design an ultra-low concentration ammonia sensor. The gas sensor system technology is suitable for online and timely
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
