Engineering Hierarchical CuO/WO<sub>3</sub> Hollow Spheres with Flower-like Morphology for Ultra-Sensitive H<sub>2</sub>S Detection at ppb Level
Highly sensitive real-time detection of hydrogen sulfide (H<sub>2</sub>S) is important for human health and environmental protection due to its highly toxic properties. The development of high-performance H<sub>2</sub>S sensors remains challenging for poor selectivity, high l...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
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| Series: | Chemosensors |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2227-9040/13/7/250 |
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| Summary: | Highly sensitive real-time detection of hydrogen sulfide (H<sub>2</sub>S) is important for human health and environmental protection due to its highly toxic properties. The development of high-performance H<sub>2</sub>S sensors remains challenging for poor selectivity, high limit detection and slow recovery from irreversible sulfidation. To solve these problems, we strategically prepared a layered structure of CuO-sensitized WO<sub>3</sub> flower-like hollow spheres with CuO as the sensitizing component. A 15 wt% CuO/WO<sub>3</sub> exhibits an ultra-high response (R<sub>a</sub>/R<sub>g</sub> = 571) to 10 ppm H<sub>2</sub>S (131-times of pure WO<sub>3</sub>), excellent selectivity (97-times higher than 100 ppm interference gas), and a low detection limit (100 ppb). Notably, its fast response (4 s) is accompanied by full recovery within 236 s. After 30 days of continuous testing, the response of 15 wt% CuO/WO<sub>3</sub> decreased slightly but maintained the initial response of 90.5%. The improved performance is attributed to (1) the p-n heterojunction formed between CuO and WO<sub>3</sub> optimizes the energy band structure and enriches the chemisorption sites for H<sub>2</sub>S; (2) the reaction of H<sub>2</sub>S with CuO generates highly conductive CuS, which significantly reduces the interfacial resistance; and (3) the hierarchical flowery hollow microsphere structure, heterojunction, and oxygen vacancy synergistically promote the desorption. This work provides a high-performance H<sub>2</sub>S gas sensor that balances response, selectivity, and response/recovery kinetics. |
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| ISSN: | 2227-9040 |