TY - JOUR
T1 - Tailoring MXene Thickness and Functionalization for Enhanced Room-Temperature Trace NO2 Sensing
AU - Hilal, Muhammad
AU - Yang, Woochul
AU - Hwang, Yongha
AU - Xie, Wanfeng
N1 - Publisher Copyright:
© 2024, The Author(s).
PY - 2024/12
Y1 - 2024/12
N2 - In this study, precise control over the thickness and termination of Ti3C2TX MXene flakes is achieved to enhance their electrical properties, environmental stability, and gas-sensing performance. Utilizing a hybrid method involving high-pressure processing, stirring, and immiscible solutions, sub-100 nm MXene flake thickness is achieved within the MXene film on the Si-wafer. Functionalization control is achieved by defunctionalizing MXene at 650 °C under vacuum and H2 gas in a CVD furnace, followed by refunctionalization with iodine and bromine vaporization from a bubbler attached to the CVD. Notably, the introduction of iodine, which has a larger atomic size, lower electronegativity, reduce shielding effect, and lower hydrophilicity (contact angle: 99°), profoundly affecting MXene. It improves the surface area (36.2 cm2 g−1), oxidation stability in aqueous/ambient environments (21 days/80 days), and film conductivity (749 S m−1). Additionally, it significantly enhances the gas-sensing performance, including the sensitivity (0.1119 Ω ppm−1), response (0.2% and 23% to 50 ppb and 200 ppm NO2), and response/recovery times (90/100 s). The reduced shielding effect of the –I-terminals and the metallic characteristics of MXene enhance the selectivity of I-MXene toward NO2. This approach paves the way for the development of stable and high-performance gas-sensing two-dimensional materials with promising prospects for future studies. [Figure not available: see fulltext.].
AB - In this study, precise control over the thickness and termination of Ti3C2TX MXene flakes is achieved to enhance their electrical properties, environmental stability, and gas-sensing performance. Utilizing a hybrid method involving high-pressure processing, stirring, and immiscible solutions, sub-100 nm MXene flake thickness is achieved within the MXene film on the Si-wafer. Functionalization control is achieved by defunctionalizing MXene at 650 °C under vacuum and H2 gas in a CVD furnace, followed by refunctionalization with iodine and bromine vaporization from a bubbler attached to the CVD. Notably, the introduction of iodine, which has a larger atomic size, lower electronegativity, reduce shielding effect, and lower hydrophilicity (contact angle: 99°), profoundly affecting MXene. It improves the surface area (36.2 cm2 g−1), oxidation stability in aqueous/ambient environments (21 days/80 days), and film conductivity (749 S m−1). Additionally, it significantly enhances the gas-sensing performance, including the sensitivity (0.1119 Ω ppm−1), response (0.2% and 23% to 50 ppb and 200 ppm NO2), and response/recovery times (90/100 s). The reduced shielding effect of the –I-terminals and the metallic characteristics of MXene enhance the selectivity of I-MXene toward NO2. This approach paves the way for the development of stable and high-performance gas-sensing two-dimensional materials with promising prospects for future studies. [Figure not available: see fulltext.].
KW - Controlled MXene thickness
KW - Enhanced MXene stability
KW - Gaseous functionalization approach
KW - Lower electronegativity functional groups
KW - Trace NO sensing
UR - http://www.scopus.com/inward/record.url?scp=85182157717&partnerID=8YFLogxK
U2 - 10.1007/s40820-023-01316-x
DO - 10.1007/s40820-023-01316-x
M3 - Article
AN - SCOPUS:85182157717
SN - 2311-6706
VL - 16
JO - Nano-Micro Letters
JF - Nano-Micro Letters
IS - 1
M1 - 84
ER -