Modulating MoS2 Substrate via d-p Orbital Hybridization Driven by π-Electron Feedback Effect for Dual-Site Adsorption Enhancement of Formaldehyde.

Abstract

Two-dimensional transition metal chalcogenides (TMCs), such as MoS2 (MS), exhibit chemically inert basal planes due to saturated intralayer coordination. This inherent inertness limits their specific recognition and adsorption of target gas molecules as gas-sensitive materials. Based on density functional theory (DFT) calculations, we report a strategy to achieve efficient formaldehyde adsorption by enhancing d-p orbital hybridization within the MS lattice to establish a π-electron feedback mechanism. Specifically, codoping the lattice with transition metal Zr atoms and nonmetallic N atoms strengthens the matrix's d-p orbital hybridization, thereby inducing a π-back-donation effect at the MS-Zr-N/formaldehyde (CH2O) interface. Notably, this π-electron feedback mechanism facilitates the formation of dual adsorption sites between the MS-Zr-N substrate and formaldehyde molecules, significantly enhancing specific adsorption capacity. Consequently, the MS-Zr-N substrate demonstrates high adsorption stability (adsorption energy: - 3.023 eV), superior sensitivity (38.47), and excellent selectivity toward formaldehyde. This work provides theoretical guidance for designing gas-sensitive materials from the perspective of orbital hybridization and interfacial electron feedback in adsorption systems.