In situ construction and sensing mechanism of TiO2–WO3 composite coatings based on the semiconductor heterojunctions

Publication date: Available online 4 June 2019Source: Journal of Materials Research and TechnologyAuthor(s): Yangguang Yao, Jianhui Yuan, Xiaoxiao Chen, Liming Tan, Qingshan Gu, Wenjie Zhao, Jieshi ChenAbstractTungsten oxide (WO3) is one of the most promising gas-sensitivity materials owing to its high decomposition temperature and stability of microstructure. The doping of oxides can significantly improve its gas-sensitivity properties. In this paper, WO3 based coatings doped with TiO2 were prepared via plasma spraying technology by using mixed feedstock suspensions containing a precursor as WCl6 and a certain ratio of nano-TiO2. The characterization of microstructures and properties of the TiO2–WO3 composite coatings were achieved and the gas sensitivity mechanism was researched. During the suspension plasma spraying, the solvent of the precursor droplets was evaporated and then the nucleation, crystallization and growth of WO3 occurred. The crystallinity and crystal grains of WO3 increased observably as the plasma spraying power improved. With the increase of TiO2 in coatings, the average grain size of the TiO2–WO3 composite coatings decreased at first and then increased. And the gas-sensitive properties of the composite coatings were significantly better than the pure WO3 coatings. The gas-sensitive properties improvement of TiO2–WO3 composite coatings doped with TiO2 was firstly caused by the decrease of grains size, which leaded to an increase of the gas adsorptio...
Source: Journal of Materials Research and Technology - Category: Materials Science Source Type: research