MXene@ZnIn ₂ S ₄ Two-Dimensional Heterostructure with Enriched Sulfur Vacancies for Resonant-Gravimetric Detection of Triethylamine at ppb Level

Developing triethylamine gas sensors with high sensitivity, fast response, superior selectivity, and room-temperature operability has long been a challenge. By correlating the mass of the adsorbed molecules to the resonance frequency, the resonant microcantilevers show promising potential for room-temperature gas detection. In this work, we present a novel MXene@ZnIn₂S₄ two-dimensional heterostructure with abundant sulfur vacancies as a sensitive material for efficient triethylamine detection. Compared with gas sensors constructed from pure 2D MXene and 2D ZnIn₂S₄ nanosheets, the MXene@ZnIn₂S₄ gas sensor exhibits significantly improved sensitivity. The MXene@ZnIn₂S₄ sensor achieves a high sensitivity variation of 16.1 Hz for 500 ppb triethylamine and demonstrates high selectivity, a low detection limit (5 ppb), and effective moisture resistance. Multiple in situ characterizations and thermodynamic analyses reveal that this remarkable gas sensing capability arises from the distinctive heterojunction, the abundance of active sites induced by surface sulfur vacancies, and the outstanding adsorption thermodynamics of MXene@ZnIn₂S₄. The combination of a 2D@2D heterostructure and microcantilever sensor paves the way to develop high-performance room-temperature gas sensors.