An ultra-sensitive NH3 gas sensor enabled by an ion-in-conjugated polycroconaine/Ti3C2Tx core–shell composite

MXenes are emerging sensing materials due to their metallic conductivity and rich surface chemistry for analytes; they, however, suffer from poor stability. Incorporation with functional polymers can largely prevent the performance decay and enhance the sensing performance. Herein, we demonstrate a...

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Bibliographic Details
Published in:Nanoscale horizons 2023-05, Vol.8 (6), p.794-802
Main Authors: Zhou, Jin, Seyed Hossein Hosseini Shokouh, Cui, Linfan, Järvinen, Topias, Pitkänen, Olli, Zhong-Peng Lv, Kordas, Krisztian
Format: Article
Language:English
Subjects:
Adsorption
Ammonia
Density functional theory
Gas sensors
Polymer matrix composites
Sensitivity enhancement
Sensors
Stability analysis
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Summary:MXenes are emerging sensing materials due to their metallic conductivity and rich surface chemistry for analytes; they, however, suffer from poor stability. Incorporation with functional polymers can largely prevent the performance decay and enhance the sensing performance. Herein, we demonstrate a core–shell composite, Ti3C2Tx@croconaine (poly(1,5-diaminonaphthalene-croconaine), PDAC) prepared by a facile in situ polymerization reaction, suitable for NH3 detection. Compared to pristine Ti3C2Tx, the sensor made of a Ti3C2Tx–polycroconaine composite exhibits a significantly enhanced sensitivity of 2.8% ppm−1 and an estimated achievable limit of detection of 50 ppb. The improved sensing performance could be attributed to the presence of PDAC facilitating the adsorption of NH3 and changing the tunneling conductivity between Ti3C2Tx domains. Density functional theory (DFT) calculations reveal that the adsorption energy of NH3 on PDAC is the highest among the tested gases, which supports the selectivity of the sensor to this analyte. Benefiting from the protection conferred by the PDAC shell, the composite has a reliable operation period of at least 40 days. In addition, we demonstrated a flexible paper-based sensor of the Ti3C2Tx@PDAC composite, without attenuated performance upon mechanical deformation. This work proposed a novel mechanism and a feasible methodology to synthesize MXene–polymer composites with improved sensitivity and stability for chemical sensing.
ISSN:2055-6764
2055-6764
DOI:10.1039/d2nh00591c