Nano-Micro Letters, Volume. 16, Issue 1, 084(2024)
Tailoring MXene Thickness and Functionalization for Enhanced Room-Temperature Trace NO2 Sensing
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.
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Muhammad Hilal, Woochul Yang, Yongha Hwang, Wanfeng Xie. Tailoring MXene Thickness and Functionalization for Enhanced Room-Temperature Trace NO2 Sensing[J]. Nano-Micro Letters, 2024, 16(1): 084
Category: Research Articles
Received: Aug. 30, 2023
Accepted: Dec. 5, 2023
Published Online: Jan. 23, 2025
The Author Email: Yang Woochul (wyang@dongguk.edu), Hwang Yongha (hwangyongha@korea.ac.kr), Xie Wanfeng (wfxie@qdu.edu.cn)