摘要： Hierarchically assembled WO3·H2O spheres have been synthesized successfully by a facile sonochemical approach using oxalic acid as capping agent. The resultant WO3·H2O spheres with diameter of 1–3μm are actually assembled by many interlaced nanosheets with thickness of 10–20nm. The as-obtained orthorhombic WO3·H2O transforms into monoclinic WO3 without obvious change in morphology through annealing and dehydration. Furthermore, such 3D hierarchical spheres exhibit a strong structure-induced improvement in gas-sensing properties to ppm-level NO2, since the specific surface of sensing material and the gas diffusion are significantly enhanced due to its porous nano/microstructure. This work presents new insight towards the design of novel gas-sensing materials and improvement of sensor performance. •Hierarchically assembled WO3·H2O are synthesized by a facile sonochemical approach.•After annealing, orthorhombic WO3·H2O transforms into monoclinic WO3.•Such WO3 architecture exhibits structure-induced enhancement of NO2 response.•Gas diffusion and mass transfer in the WO3 architecture are significantly enhanced. 出版者： Elsevier B.V 出版日期： 2013-11-15 出處： Materials letters, 2013-11, Vol.111, p.32-34 資源來源： Elsevier ScienceDirect Journals Complete 版權： 2013 Elsevier B.V. 識別號： ISSN: 0167-577X 識別號： EISSN: 1873-4979 識別號： DOI: 10.1016/j.matlet.2013.08.041
