Adsorption chemistry of co-doped graphene nanoribbon and its derivatives towards carbon based gases for gas sensing applications: Quantum DFT investigation

Sensing of the toxic gases plays a vital role in the human life to improve their health aspects and the quality of life. Using the first-principles calculations combined with density functional theory (DFT), the authors in this research work have explored the adsorption energy and electronic features of co-doped armchair graphene nanoribbon (ArGNR) and its derivatives, such as the co-doped armchair graphene oxide nanoribbon (ArGONR) and co-doped armchair reduced graphene oxide nanoribbon (ArRGONR) with boron and phosphorus (BP) atoms. A comparative study of detection of toxic carbon based gases (CO, CO2, CH4) on co-doped graphene nanoribbon (BP-ArGNR), and its derivatives such as BP-ArGONR (addition of more oxygen atoms in pristine ArGNR) and BP-ArRGONR (addition of less oxygen atoms in pristine ArGNR) has been performed. To evaluate the sensing of carbon based gases, their adsorption energies, binding distances, charge transfer, band structures and density of states have been studied for different variants. Before modification, adsorption energies for BP-ArGNR have been found to be smaller than the BP-ArGONR for CO, CO2 and CH4 molecules, thereby showing physisorption mechanism. Our computational results also revealed that after modification with oxygen atoms, BP-ArGONR shows relatively more negative value of adsorption energy in comparison to the pristine ArGNR (PR-ArGNR) for CO, CO2 and CH4 molecules, thereby showing chemisorption phenomenon. Band structure analysis predicts large band gap variations for BP-ArGONR as compared to PR-ArGNR. Thus, the authors concluded that after modification of graphene surface, enormous changes are observed in adsorption energies and band gap for BP-ArGONR towards all carbon based gases under study and hence significantly enhance the sensing performance of pristine graphene.