Heterojunction and exposed facet engineering of ZnO/ WO3 flower structure for fast and sensitive low-concentration NO2 sensing. (July 2023)

• Record Type: Journal Article
• Authors: Wei, Shaohong; Chang, Gaofeng; Liu, Yang; Wu, Yongdong; Zhang, Yan; Hu, Yueli; Zhang, Wei
• Is Part Of: Materials research bulletin. Volume 163(2023)
• Publication Date: 2023-07
• Subjects: ZnO/h-WO3 -- NO2 sensing -- Heterostructure -- Exposed facet; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2023.112218
• Languages: English
• ISSNs: 0025-5408

Abstract

Highlights: Unique silybum flower-like ZnO/ hexagonal WO3 heterostructure was synthesized. Novel synergy of heterojunction and exposed (001) facet with more oxygen vacancies. Heterojunction and exposed facet engineering for fast/low concentration NO2 sensing. High response (5.9) and quick response (7 s)/recovery time (9 s) to 100 ppb NO2 . Abstract: A novel silybum flower-like ZnO/ hexagonal WO3 heterostructure is synthesized via hydrothermal method and applied in gas sensors for NO2 detection. The morphology, composition, and possible growth mechanism are systematically investigated by a series of characterizations. In comparison with the pure WO3 and other ZnO/WO3 samples, the silybum flower-like ZnO/ hexagonal WO3 sensor presents superior NO2 sensing performance at 190 °C, particularly at low concentrations, consisting of high response (5.9), quick response (7–12 s)/recovery time (9–13 s), strong selectivity and stability toward 100 ppb NO2 . The excellent sensing characteristics are attributed to the synergy of heterojunction and exposed (001) facet with more oxygen vacancies. Furthermore, the well-defined open flower structure provides unique opportunities to form n-n heterostructures, inducing the adequate sensing reactions and ultrafast the response/recovery kinetics. The findings in this study open a new route for WO3 -based hierarchical materials to detect NO2 efficiently and accurately. Graphical abstract: Image, graphical abstract