Direct confirmation of confinement effects by NiO confined in helical SnO2 nanocoils and its application in sensors

Confinement effects in space-confined catalysts are attracting attention due to their advantages, like size control, unique nanoscale chemical environments and designable nature of the active sites. There are rarely works on the direct confirmation of confinement effects because of restrictions of n...

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Bibliographic Details
Published in:Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2022-02, Vol.10 (6), p.2786-2794
Main Authors: Hu, Qingmin, Wu, Cuixia, Dong, Zhe, Zhang, Gaixia, Ma, Zhiheng, Wang, Xiaohong, Sun, Shuhui, Xu, Jiaqiang
Format: Article
Language:English
Subjects:
Atomic layer epitaxy
Catalysts
Confined spaces
Confinement
Enrichment
Fabrication
Gas sensors
Nanoparticles
Nickel oxides
Recovery time
Response time
Sensors
Synergistic effect
Tin dioxide
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Summary:Confinement effects in space-confined catalysts are attracting attention due to their advantages, like size control, unique nanoscale chemical environments and designable nature of the active sites. There are rarely works on the direct confirmation of confinement effects because of restrictions of nanoscale confined space. Herein, we report the fabrication of a novel structure that is composed of NiO nanoparticles confined in SnO2 nanocoils (I-NiSnNCs) via atomic layer deposition (ALD). The I-NiSnNCs displayed higher sensing performance towards hydrogen than the NiO–SnO2 film, NiO outside NiSnNC and NiO both outside and inside NiSnNC sensors. The I-NiSnNC sensor shows a response to about 7 to 50 ppm H2 with a 2.4 s response time and 4.2 s recovery time at 260 °C and excellent repeatability. The synergistic effect of interfacial sites is attributed to the reaction between adsorbed H on NiO and adsorbed O at interfacial active sites. The “funneling effect” formed because the enrichment effect of hydrogen on the NiO surface is higher than that of the gas state as the adsorbed H quickly reacts at interfacial active sites. The enrichment effects of H2 lead to high sensing performance to H2, and the high reactivity of H2 at interfacial active sites leading to rapid transfer of electrons is responsible for the high response/recovery performance. The gas sensor offers a new way to directly confirm the confinement effect. And the confinement effects in return give a novel way to design sensing materials.
ISSN:2050-7488
2050-7496
DOI:10.1039/d1ta08630h