Paper Title
OPTIMIZING MXENE FLAKE THICKNESS AND FUNCTIONALIZATION FOR ENHANCED ROOM-TEMPERATURE NO2 SENSING

Abstract
This study focuses on optimizing Ti3C2TXMXene flakes for improved room-temperature trace NO2 sensing. Through a hybrid approach involving high-pressure processing and controlled functionalization techniques, precise control over MXene flake thickness and termination is achieved. Defunctionalization followed by refunctionalization with iodine vaporization significantly enhances MXene's surface area (36.2 cm2 g−1), oxidation stability (21 days/80 days in aqueous/ambient environments), and film conductivity (749 S m−1). Consequently, notable enhancements in gas-sensing performance, including sensitivity (0.1119 Ω ppm−1), response time (90/100 s for response/recovery), and selectivity towards NO2, are observed. Furthermore, utilizing highly hydrophobic and trace gas-sensitive I-MXene for exhaled breath analysis is currently being explored as an extension of this study. These findings underscore the potential of MXene-based materials for high-performance gas-sensing applications and breath analysis applications. Keywords - 2D MXene, Few-Layer MXene, Functionalization of MXene, Gas Sensor, Trace NO2 Detection.