Unexpected Bi-functional Co-g-GaN monolayer for detecting and scavenging toxic gases

Abstract

Exploring effective detection strategies for toxic gases is important for environmental protection. Herein, based on first principles study, we investigated the adsorption configuration, electron localization function (ELF), charge transfer (QT), charge density difference (CDD), band structures, density of state (DOS), work function (Φ), recovery time (τ) and potential applications of toxic gases molecule (CO, NO, NO2, H2S and NH3) adsorption on cobalt modified graphene-like gallium nitride (Co-g-GaN) monolayer. It is found that Co atom prefer to locate on the top of N atom of GaN. Their adsorption on Co-g-GaN monolayer is an exothermic reaction and chemisorption. CO, NO and NO2 molecules are electron-acceptors, while H2S and NH3 molecules are electron-donors. The results of DOS indicate that Co-g-GaN monolayer had strong interactions with CO, NO and NO2 molecules. Except for NO2 molecules, the Φ of Co-g-GaN was reduced after the adsorption of other gas molecules. More importantly, Co-g-GaN monolayer can be used not only as a detector for H2S (1.2 ×10−6 s) and NH3 (0.30 s) molecules, but also as a gas scavenger to remove of CO, NO and NO2 molecules. This work provides important guidance for the designing g-GaN-based gas detectors and scavenger.