Nitrogen-Doped Graphene Quantum Dots for Efficient Detection of Toxic Gas

Owing to their adjustable optoelectronic and adsorption characteristics, graphene quantum dots (GQDs) have become a potential material to manufacture effective gas sensors. Our present work deals with the study of interaction of a pristine graphene quantum dot (GQD) and a pyridinic nitrogen-doped defective graphene quantum dot (4N-GQD) with various toxic gases such as sulfur dioxide (SO₂), hydrogen fluoride (HF), hydrogen chloride (HCl), methane (CH₄), and carbon monoxide (CO). The 4N-GQD system has revealed strong interaction with these toxic gases in comparison to their pristine counterpart, which is because of the formation of an active region due to charge accumulation at the nitrogen-doped site. The adsorbate–adsorbent interaction in these systems has been studied at the molecular level employing density functional theory (DFT). Our findings suggest that the 4N-GQD system would be an effective adsorbent for a variety of toxic gases. These findings will help to steer the development of gas sensors with desirable features.