Enhanced Gas-Sensing Properties of the Hierarchical TiO2 Hollow Microspheres with Exposed High-Energy {001} Crystal Facets

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• 作者：Yong Yang ; Yan Liang ; Guozhong Wang ; Liangliang Liu ; Cailei Yuan ; Ting Yu ; Qinliang Li ; Fanyan Zeng ; Gang Gu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：November 11, 2015
• 年：2015
• 卷：7
• 期：44
• 页码：24902-24908
• 全文大小：440K
• ISSN：1944-8252

文摘

Anatase hierarchical TiO₂ with innovative designs (hollow microspheres with exposed high-energy {001} crystal facets, hollow microspheres without {001} crystal facets, and solid microspheres without {001} crystal facets) were synthesized via a one-pot hydrothermal method and characterized. Based on these materials, gas sensors were fabricated and used for gas-sensing tests. It was found that the sensor based on hierarchical TiO₂ hollow microspheres with exposed high-energy {001} crystal facets exhibited enhanced acetone sensing properties compared to the sensors based on the other two materials due to the exposing of high-energy {001} crystal facets and special hierarchical hollow structure. First-principle calculations were performed to illustrate the sensing mechanism, which suggested that the adsorption process of acetone molecule on TiO₂ surface was spontaneous, and the adsorption on high-energy {001} crystal facets would be more stable than that on the normally exposed {101} crystal facets. Further characterization indicated that the {001} surface was highly reactive for the adsorption of active oxygen species, which was also responsible for the enhanced sensing performance. The present studies revealed the crystal-facets-dependent gas-sensing properties of TiO₂ and provided a new insight into improving the gas sensing performance by designing hierarchical hollow structure with special-crystal-facets exposure.