Ultra-high sensitivity for isoamyl alcohol based on g-C3N4 nanosheets incorporated Ag nanoparticles loaded Er0.05La0.95FeO3 heterojunctions with enhanced moisture resistance

The volatile of isoamyl alcohol released from the stored wheat increased with the storage extending, making it one of the potential biomarkers for the early-stage of wheat mildew. Currently, there is a scarcity of chemiresistors for isoamyl alcohol detection, which suffer from low sensitivity. The team of material scientists led by Professor Chao Zhang reported that LaFeO₃-based sensing materials demonstrated remarkable sensitivity for isoamyl alcohol (DOI: 10.1039/D3TA05718F, 10.1007/s11666-024-01740-4). However, it’s essential to note that there is still potential for lowering the optimal operating temperature and enhancing moisture resistance. Loading noble metal particles (Pt, Au, and Ag) on the surface of metal oxide semiconductors (MOS) proves to be an effective strategy to reduce the optimal operating temperature. Polymers with nanostructures usually possess a relatively robust capacity for adsorption and desorption of water molecules, which may enhance the moisture resistance of MOS-based sensors.

Based on the forementioned background, a team of material scientists led by Prof. Chao Zhang from the Institute of Surface Engineering at Yangzhou University, China, recently reported the well-designed LaFeO₃-based heterojunction, which enhance the sensing performance at high relative humidity.

The team published their research in Journal of Advanced Ceramics on 07 April, 2024.

Ag/ELFO were prepared by one-step hydrothermal, and g-C₃N₄ nanosheets were incorporated on the surface of Ag/ELFO by electrostatic self-assembly method. Ag nanoparticles further improve the sensitivity of Er_0.05La_0.95FeO₃ for isoamyl alcohol gas and reduce the optimal operating temperature. After the combination of g-C₃N₄, although the response value of the sensor was slightly reduced, the moisture resistance was greatly improved.

g-C₃N₄/Ag/Er_0.05La_0.95FeO₃ sensor performed superior sensitivity for isoamyl alcohol at 20% RH and optimal operating temperature (225^oC) (443.3 to 25 ppm) with low limit of detection (75 ppb), excellent selectivity, repeatability, and long-term stability (434.3 ± 19.4 for 15 days). This sensor exhibited superior sensitivity for isoamyl alcohol than the reported gas sensors. The presence of Ag⁺ in the precursor impeded the growth of LaFeO₃ grains. Furthermore, the spillover effect and catalytic action of Ag particle sites and the reduced adsorption activation energy improve the isoamyl alcohol gas response behavior of Er_0.05La_0.95FeO₃. The improvement of moisture resistance after the combination of g-C₃N₄ improves the isoamyl alcohol sensing performance of the sensor at 20% RH.

The practical application potential of the sensor was investigated by detecting the volatile gases released from wheat in different storage periods. With the extension of storage time (1, 2, 3, 5, and 7 days), the response of g-C₃N₄/Ag/Er_0.05La_0.95FeO₃-based sensor to VOCs increased from 18.2 to 734.1, which is completely consistent with the sudden increase of isoamyl alcohol volatilization within 5-7 days. Herein, the as-fabricated sensor has a high potential for application as practical gas-sensing devices for wheat mildew detection.

This work is supported by the Outstanding Youth Foundation of Jiangsu Province of China under Grant No. BK20211548, Qinglan Project of Yangzhou University, and Yangzhou Science and Technology Plan Project (YZ2023246).

About Journal of Advanced Ceramics

Journal of Advanced Ceramics (JAC) is an international journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press on behalf of the State Key Laboratory of New Ceramics and Fine Processing (Tsinghua University) and the Advanced Ceramics Division of the Chinese Ceramic Society, and exclusively available via SciOpen. JAC has been indexed in SCIE (IF = 16.9, top 1/28, Q1), Scopus, and Ei Compendex.

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