Self-Powered Wearable Gas Sensors Based on l-Ascorbate-Treated MXene Nanosheets and SnO2 Nanofibers

Self-powered sensing devices have aroused the regime of flexible, portable, and wearable gas sensors due to their economic and environmentally friendly nature. Highly active two-dimensional MXene with high metallic conductivity, large surface area, and surface chemistry has shown great potential for sensing applications except for their oxidation degradation. The present work reports the development of a humidity tolerant self-powered gas sensor comprising nanocomposite of sodium l-ascorbate-treated MXene and SnO2 nanofiber-based gas sensor and piezoelectric pressure sensor (PPs). The interfacial engineering of MXene with SnO2 was significantly found to enhance both the pressure sensitivity and room-temperature NO2 gas sensing performance. The SnO2/MXene nanocomposite-based gas sensor exhibits ∼8- and 34-fold response toward NO2 gas as compared to SnO2 nanofibers and MXene sheets, respectively, along with a lower detection limit of 0.03 ppb NO2 and power consumption as low as 1.2 μW. Moreover, the SnO2/MXene nanocomposite-based PPs exhibits a high sensitivity of 2.088 kPa–1 under the pressure range of 1.63–6.23 kPa with a fast response time (265 ms) and recovery time (75.5 ms). In addition, the PPs can produce a power density of 21.80 mW m–2, sufficient enough to drive the gas sensor and demonstrate its potential application for self-powered wearable gas sensors.