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<p>Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) and transition metal
carbides/nitrides (MXenes), have been recently receiving attention for gas sensing applications
due to their high specific area and rich surface functionalities. However, using pristine 2D
materials for gas-sensing applications presents some drawbacks, including high operation
temperatures, low gas response, and poor selectivity, limiting their practical sensing
applications. Moreover, one of the long-standing challenges of MXenes is their poor stability
against hydration and oxidation in a humid environment, which negatively influences their long-
term storage and applications. Many studies have reported that the sensitivity and selectivity of
2D materials can be improved by surface functionalization and hybridization with other
materials.</p><p>In this work, the effects of surface functionalization and/or hybridization of these two
materials classes (TMDCs and MXenes) on their gas sensing performance have been
investigated. In one of the lines of research, 2D MoS2 nanoflakes were functionalized with Au
nanoparticles as a sensing material, providing a performance enhancement towards sensing
of volatile organic compounds (VOCs) at room temperature. Next, a nanocomposite film
composed of exfoliated MoS2, single-walled carbon nanotubes, and
Cu(I)−tris(mercaptoimidazolyl)borate complexes was the sensing material used for the design
of a chemiresistive sensor for the selective detection of ethylene (C2H4). Moreover, the
hybridization of MXene (Ti3C2Tx) and TMDC (WSe2) as gas-sensing materials was also
proposed. The Ti3C2Tx/WSe2 hybrid sensor reveals high sensitivity, good selectivity, low noise
level, and ultrafast response/recovery times for the detection of various VOCs. Lastly, we
demonstrated a surface functionalization strategy for Ti3C2Tx with fluoroalkylsilane (FOTS)
molecules, providing a superhydrophobic surface, mechanical/environmental stability, and
excellent sensing performance. The strategies presented here can be an effective solution for
not only improving materials' stability, but also enhancing sensor performance, shedding light
on the development of next-generation field-deployable sensors.</p>
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| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/14866332 |
| Date | 01 September 2021 |
| Creators | Yen-yu Chen (11036556) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/2D_MATERIALS_FOR_GAS-SENSING_APPLICATIONS/14866332 |
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