Ultra-fast and high sensitivity of NO₂ detection at room temperature and ultraviolet with a self-assembled ZnMnO/MXene-OH nanocomposite

Metal oxide semiconductor (MOS) gas sensor is an effective tool for NO₂ detection. In this work, a NO₂ sensor based on MXene-OH/ZnMnO was fabricated via a seed layer induced self-assembly method, exhibiting remarkable gas response value(280) to 100 ppm NO₂ under 25℃ and ultraviolet activation. Besides, the prepared sensor presents ultra-fast response and recovery speeds (8/40 s), low detection limit (250 ppb), and high selectivity. The enhanced sensing performance was explained by the first-principles calculations, showing that the increased electrical conductivity, more electron transfer numbers and higher adsorption energy promotes effective transport of charge carriers on the surface of sensing materials and NO₂ gas molecules.