Designed construction of PdO@WO3 core–shell architecture as a high-performance acetone sensor

Abstract

In this study, a structurally well-designed PdO@WO3 core–shell, p–n heterojunction architecture was fabricated using a facile hydrothermal method. Its material characterization was performed via X-ray diffractometry, X-ray photoelectron spectroscopy, electron scanning microscopy, and transmission electron microscopy analyses. Besides, the gas sensing properties of pure WO3, PdO–WO3, and PdO@WO3 nanocomposites were investigated. By benefiting from the unique synergistic effect between catalytic sensing and p–n heterojunction structure, the PdO@WO3 core–shell nanostructure showed considerably enhanced acetone sensing performance compared with the other structures; especially, its response toward 50 ppm acetone gas was up to 40, four times higher than that of the pure WO3 sensor. Its response/recovery times were also significantly reduced and its optimal operating temperature decreased from 250 °C to 200 °C. Finally, the possible sensing mechanism for the proposed PdO@WO3 core–shell, p–n heterojunction architecture is discussed here; the considerable enhancement in the acetone sensing capability could be attributed to its well-designed fabrication.