Ab-initio characterization of iron-embedded nitrogen-doped graphene as a toxic gas sensor

Abstract

Special binding sites in graphene are beneficial for near-surface interaction. These binding sites, which are supplied by single-atom catalysts, change the electronic characteristics of graphene and its derivatives, greatly expanding its potential use as gas sensors. Iron–nitrogen–carbon is reflected as one of the most effective substitutes for platinum in oxygen reduction reactions. The selection for carbon-enclosed FeN4 moieties, which serve as catalytically active centers, is among the top priorities. Current research focuses heavily on carbon-enclosed FeN4 moieties from a gas sensing perspective. In the present work, transition metal atom iron supported on nitrogen-doped graphene (FeN/G) was analyzed by density functional theory. The effect of gas adsorption on the structural and electronic properties was investigated with adsorption energy, charge transfer, work function, and band structure. The results indicate the chemisorption nature of carbon monoxide (CO), nitrogen oxide (NO), and nitrogen dioxide (NO2) with strong adsorption energies of − 1.641 eV, − 2.081 eV, and − 1.345 eV. They induced spin polarization when adsorbed on the graphene support, which drastically modulated the electronic characteristics of the substrate. While other gas molecules of carbon dioxide, hydrogen disulfide, and ammonia (CO2, H2S, and NH3) with adsorption energies of − 0.154 eV, − 0.371 eV, and − 0.460 eV were physisorbed and served as electron donors, sulfur dioxide (SO2) exhibited weak chemisorption at a value of − 0.620 eV. Nitrogen-containing gas molecules of NO, NO2, and NH3 showed band gap shortening with increasing conductivity as compared to bare iron embedded graphene supported structure. Based on the investigation, the structure has potential application for the detection of NO and NO2 and other gases.