Hierarchical flower-like WO3-based sensor with high sensitivity and low detection limit for indoor xylene rapid detection

Tunable WO₃ microstructures are achieved via solvothermal synthesis. • Ultra-fast response (1 s) and low detection limit (52 ppb) toward xylene. • Synergistic mechanism of size effect, active facets and oxygen vacancies. • Low-power indoor xylene real-time monitoring prototype. As a common indoor aromatic volatile organic pollutant, accurate and sensitive monitoring of xylene is essential for residential health protection. In this work, monoclinic WO 3 materials with tunable microstructures were synthesized via a solvothermal synthesis by adjusting the water/ethanol solvent ratio. The regulation effect of solvent composition on crystal facet exposure, defect content and morphology of the materials was systematically analyzed. The gas sensing measurements reveal that the hierarchical flower-like WO 3 microsphere sensor (synthesized at water/ethanol = 2:1) exhibits a response of 25.9 toward 100 ppm xylene at 220 °C, which is 3-fold higher than that of the sensor fabricated with pure water as the solvent. It also features 1 s ultrafast response, excellent selectivity, 30-day long-term stability, and a 52 ppb detection limit. The superior performance originates from the combined contributions of the nanosheet size effect, efficient gas diffusion pathways of the hierarchical architecture, and abundant surface active sites. The portable early warning system developed with this material enables real-time indoor xylene monitoring, providing a new strategy for high-performance gas sensing material design. The WO 3 -2 sensor exhibits an ultrafast response of 1 s and a recovery time of 47 s toward xylene, with a response of 4.5 at 1 ppm and a calculated limit of detection (LOD) as low as 52 ppb. The xylene detection prototype developed based on this sensor enables real-time concentration monitoring and multi-gradient alarm of target gas in indoor scenarios, providing a practical solution for on-site xylene detection in confined spaces such as homes. Download: Download high-res image (99KB) Download: Download full-size image