Abstract
Surface modification is a reliable method to enhance the sensing properties of pristine graphene by increasing active sites on its surface. Herein, we investigate the interactions of the gas molecules such as NH3, NO, NO2, H2O, and H2S with a zinc oxide (ZnO)–graphene hybrid nanostructure. Using first-principles density functional theory (DFT), the effects of gas adsorption on the electronic and transport properties of the sensor are examined. The computations show that the sensitivity of the pristine graphene to the above gas molecules is considerably improved after hybridization with zinc oxide. The sensor shows low sensitivity to the NH3 and H2O because of the hydrogen-bonding interactions between the gas molecules and the sensor. Owing to observable alterations in the conductance, large charge transfer, and high adsorption energy; the sensor possesses extraordinary potential for NO and NO2 detection. Interestingly, the H2S gas is totally dissociated through the adsorption process, and a large number of electrons are transferred from the molecule to the sensor, resulting in a substantial change in the conductance of the sensor. As a result, the ZnO–graphene nanosensor might be an auspicious catalyst for H2S dissociation. Our findings open new doors for environment and energy research applications at the nanoscale.
Highlights
There are presently great efforts being made in developing novel gas sensors centered around new nanomaterials for the detection of toxic gases since they offer higher sensitivity, selectivity, and reliability; as well as immediate response and recovery at low cost
This paper presents first-principles calculations based on density functional theory (DFT) in combination with the non-equilibrium Green’s Function (NEGF) method performed in the Atomistix ToolKit (ATK)
Our DFT calculations show that zinc oxide (ZnO) prefers to place itself perpendicular with respect to the graphene plane, while the Zn atom heading to the C atoms and the O atom way around
Summary
There are presently great efforts being made in developing novel gas sensors centered around new nanomaterials for the detection of toxic gases since they offer higher sensitivity, selectivity, and reliability; as well as immediate response and recovery at low cost. One of the most significant advantages that nanostructure-based sensors have over conventional microsensors is the high surface-to-volume ratio. This is a crucial parameter since it defines the sensitivity of the gas sensors. Graphene’s amazing properties have attracted considerable interest in the area of gas sensing since they enable the improvement of miniaturized sensors at low cost and power consumption [3,4,5]. Because of the weak interactions between π electrons of graphene’s surface and the gas molecules, pristine graphene has shown limitations for the recognition of individual gas particles [9,10], exhibiting low sensitivity to common
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