A magnetic nanosensor for flammable VOCs detection: unveiling Mn2SO2 monolayer performance through ab initio modelling

Abstract

Effective victim detection during fire disasters requires reliable identification of flammable VOCs under high-temperature conditions. Magnetic VOC sensors based on two-dimensional nanomaterials offer a promising solution. In this work, a Mn2SO2 monolayer is investigated as a magnetic VOC sensor for eleven fire-related VOCs using density functional theory (DFT). Mn2SO2 exhibits intrinsic spin polarization and ferromagnetism that support magnetic sensing. Adsorption results show strong chemisorption for Benzaldehyde, Butanol, Heptane, Hexanal, Methylamine, Dimethyl disulfide, Dimethyl trisulfide, Pyridine, and Toluene, with adsorption energies from −1.53 to −0.46 eV, whereas Butanone (−0.34 eV) and Octane (−0.12 eV) show weak physisorption. Charge transfer, electron density difference, and ELF analyses reveal predominantly ionic interactions, with Mn2SO2 acting as an electron acceptor. Sensor responsiveness assessed via work-function modulation and magnetic-moment variation indicates high sensitivity, particularly for Pyridine (42.81%), Dimethyl disulfide (33.07%), Butanol (15.57%), and Toluene (15.84%). Ab initio molecular dynamics at 400 K confirm thermal stability and structural integrity on the picosecond timescale. Pyridine and Dimethyl disulfide emerge as the most promising detection targets due to high sensitivity and fast recovery times. These results highlight Mn2SO2 as a promising candidate for the future generation of magnetic VOC sensors in fire-disaster victim detection.