High sensitivity of s-triazine based g-C3N4 surface to pollutant gases

Abstract

Rapid detection of harmful airborne substances caused by daily activities and industrial activity is vital. In the current study, the applicability of s-triazine based g-C3N4 nanosheet as a potential sensor for environmentally dangerous gases, NO, N2O, NO2, SO, SO2, and SO3, was investigated using the density functional theory and non-equilibrium Green's function (NEGF) method. Sulfur-containing gases exhibited stronger interactions with the surface. The obtained adsorption energies are in the range of −0.21 to −1.13 eV, which is associated with charge transfer in the range of −0.09 to −0.29 e. The molecules' overall structures are preserved during the adsorption process. The sensitivity of the surface to the adsorbed molecules was confirmed by analyzing the work function changes and calculating the transmission coefficients using the NEGF approach. All adsorbate species, except SO3, have short recovery times of up to 3.9 s at room temperature, proving the efficiency of this surface as a viable sensor material. Furthermore, by analyzing the humidity impact, the g-C3N4 ability as a sensor in more realistic conditions was also validated. The results indicate that the g-C3N4 surface can be an excellent candidate for toxic gas detection with high selectivity and sensitivity.