Passivation of MXene via atomic layer deposition of SnO2 to achieve improved NO2 sensing

Abstract

MXene is a promising candidate for low power electronic devices, such as gas sensor at room temperature. However, achieving rapid response and complete recovery and simultaneously addressing the issue of baseline drift due to the oxidation of MXene are challenging for MXene sensors. Herein, we demonstrate a general strategy by using atomic layer deposition (ALD) to passivate Ti3C2Tx MXene. The abundant hydroxyl groups on MXene, which could lead to the oxidation of MXene, facilitate efficient deposition of SnO2. Gas sensor tests reveal that the passivated MXene@SnO2 exhibits a response of 35.2% to 20 ppm NO2, which is approximately three times higher than that of pure MXene. Importantly, the response time to NO2 was as fast as 18 s, with full and complete recovery to baseline within 27 s. Our strategy highlights the prospects of utilizing ALD technique for the development of MXene-based gas sensors.