The adsorption and sensor properties of NH3 and H2S on the C3N3 sheet by DFT and NCI analysis

The surge in the development of sensors that can precisely and selectively detect dangerous compounds, especially cyanides and fluorides, is growing steadily. In present study, sensing capability of a carbon nitride (C₃N₃) sheet was examined for accurately detecting NH₃ and H₂S applying a density functional theory (DFT) technique. Analysis of interaction energy indicates that H₂S forms a strong bond with the C₃N₃ sheet, likely due to chemical bonding. On the other hand, NH₃ is adsorbed onto surface through poor van der Waals (vdW) forces. To fully comprehend bonding interactions of NH₃ and H₂S with the C₃N₃ layer, non-covalent interaction (NCI), natural bond orbital charge transfer (Q_NBO), and frontier molecular orbitals (FMO) have been employed. The ΔE_ints for the NH₃@C₃N₃ and H₂S@C₃N₃ complexes were determined to be −44.16 and −58.19 kJ mol⁻¹, respectively. The NH₃ and H₂S analytes, when interacting with the C₃N₃ sheet, show notable differences in their band gap energy (E_g) during the FMO measurement, ranging from 3.59 to 2.42 eV. This indicates existence of robust NCIs. Furthermore, presence of NCIs among complexes has been verified by NCI-RDG analysis. The NH₃@C₃N₃ compound has a brief recovery time of 2.428 × 10⁻⁶ s, which simplifies the desorption process. The significant selectivity of a monolayer towards analytes, together with the potential findings, will offer practical recommendations to experimentalists for constructing extremely sensitive sensors for NH₃ and H₂S utilizing a C₃N₃ sheet.