Adsorption probability of CH4, H2O and H2 in two-dimensional zinc oxide matrix: A prediction by DFT analysis

The aim of the paper is to investigate the physisorption probability of CH
4
, H
2
O and H
2
in graphene like two-dimensional (2D) Zinc oxide monolayer (g-ZnO) using density functional theory (DFT) incorporated with Quantumwise Atomistix Toolkit (ATK) (v.2016.4). For all the species, the adsorption distance, adsorption energy and charge transfer were calculated for three different adsorption sites on g-ZnO viz., atop Zn atom, atop oxygen atom and atop hollow position. It was found that H
2
O and CH
4
show considerable adsorption probability in g-ZnO whereas H2 shows weak physisorption. Considerably high adsorption energy and charge transfer of H
2
O indicate that g-ZnO is suitable for designing humidity sensor.