University of Oulu

ACS Appl. Mater. Interfaces 2023, 15, 5, 7063–7073

Highly selective H₂S gas sensor based on Ti₃C₂Tₓ MXene–organic composites

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Author: Hosseini Shokouh, Seyed Hossein1; Zhou, Jin1; Berger, Ethan1;
Organizations: 1Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, P.O. Box 4500, FIN-90014 Oulu, Finland
2Department of Applied Physics, Aalto University, FIN-00076 Aalto, Finland
3Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Aapistie 5A, 90220 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 8.3 MB)
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Language: English
Published: American Chemical Society, 2023
Publish Date: 2023-08-11


Cost-effective and high-performance H₂S sensors are required for human health and environmental monitoring. 2D transition-metal carbides and nitrides (MXenes) are appealing candidates for gas sensing due to good conductivity and abundant surface functional groups but have been studied primarily for detecting NH₃ and VOCs, with generally positive responses that are not highly selective to the target gases. Here, we report on a negative response of pristine Ti₃C₂Tₓ thin films for H₂S gas sensing (in contrast to the other tested gases) and further optimization of the sensor performance using a composite of Ti₃C₂Tₓ flakes and conjugated polymers (poly[3,6-diamino-10-methylacridinium chloride-co-3,6-diaminoacridine-squaraine], PDS-Cl) with polar charged nitrogen. The composite, preserving the high selectivity of pristine Ti₃C₂Tₓ, exhibits an H₂S sensing response of 2% at 5 ppm (a thirtyfold sensing enhancement) and a low limit of detection of 500 ppb. In addition, our density functional theory calculations indicate that the mixture of MXene surface functional groups needs to be taken into account to describe the sensing mechanism and the selectivity of the sensor in agreement with the experimental results. Thus, this report extends the application range of MXene-based composites to H₂S sensors and deepens the understanding of their gas sensing mechanisms.

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Series: ACS applied materials & interfaces
ISSN: 1944-8244
ISSN-E: 1944-8252
ISSN-L: 1944-8244
Volume: 15
Issue: 5
Pages: 7063 - 7073
DOI: 10.1021/acsami.2c19883
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
222 Other engineering and technologies
Funding: This work was financially supported in part by the University of Oulu (projects: Entity, ROAR, and Memristors and neuromorphic sensors from vertically aligned layered materials). We acknowledge funding from the EU Erasmus + programme (project: TACMEE), and the Academy of Finland (Center of Excellence Program in Life-inspired Hybrid Materials (LIBER), and projects: 311058, 325185, and 330214). We thank the personnel of the Centre for Material Analysis at the University of Oulu for providing us with technical assistance. We also thank CSC Finland for the generous grants of computer time.
Academy of Finland Grant Number: 311058
Detailed Information: 311058 (Academy of Finland Funding decision)
325185 (Academy of Finland Funding decision)
330214 (Academy of Finland Funding decision)
Copyright information: © 2023 The Authors. Published by American Chemical Society.