MOF-Derived ZnO/Ti3C2Tx MXene Heterostructures for Ultrafast ppb-Level Detection of H2 and NO2 Gases

Metal-organic frameworks (MOFs) are regarded as potential candidate materials with great application prospects in the field of gas sensing. In this study, MOF derivatives were anchored onto MXene sheets through self-assembly technology to prepare a heterojunction material ZnO/Ti 3 C 2 T x MXene with high specific surface area, achieving ultrafast dual gas sensing behavior for H 2 /NO 2 . At a low temperature of 80°C, the ZnO/ Ti 3 C 2 T x MXene heterojunction sensor exhibited an ultrafast response (23.17%) to 500 ppb H 2 within 3.2   s. After a moderate temperature increase to 180°C, it also demonstrated significant sensing performance (46.3%) to 500 ppb NO 2 within 4   s. The electronic interaction mechanism of ZnO/ Ti 3 C 2 T x MXene heterostructures in H 2 and NO 2 detection was revealed through density functional theory calculations and in-situ Raman spectroscopy, clarifying the influence of interfacial charge transfer on sensing performance. Heterogeneous structures achieve the regulation of gas adsorption-induced electron rearrangement and carrier modulation by constructing interface charge-regulating channels, significantly enhancing the response rate, selectivity and reversibility in the detection of H 2 and NO 2 , thereby enabling highly sensitive and trace detection of the two gases.