Enhancing the Vibrational Sensitivity of Graphene via Substitutional Doping for Multimodal Gas Sensing Applications – A DFT Study

Graphene’s exceptional properties make it a leading candidate for gas sensing, but enhancing selectivity and multimodal detection remains a challenge. Using density functional theory (DFT), we systematically investigated vibrational frequency shifts in graphene doped with Au, Ag, Cu, Ni, and Pt upon adsorption of CO, CO₂, NO, and NO₂. Our results reveal that Au-doped graphene is most sensitive to CO and CO₂, while Cu-doped graphene shows the strongest response to NO₂. Both Au- and Cu-doped systems exhibit pronounced sensitivity to NO. Importantly, distinct mode-dependent responses enable discrimination among gases, establishing substitutionally doped graphene as a promising platform for multimodal sensing. These findings provide a predictive framework for designing advanced, selective, and vibration-based gas sensors.