Enhanced Gas-Sensing Properties of the Hierarchical TiO₂ Hollow Microspheres with Exposed High-Energy {001} Crystal Facets.
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.
Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, School of Physics, Communication and Electronics, Jiangxi Normal University , Nanchang 330022, Jiangxi, P.R. China.
Yong
Y
Yang
Department of Science Education, Jiangxi University of Technology , Nanchang 330098, Jiangxi, P.R. China.
Yan
Y
Liang
Key Laboratory of Materials Physics, Centre for Environmental and Energy Nanomaterials, Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences , Hefei 230031, P.R. China.
Guozhong
G
Wang
School of Physics and Technology, Wuhan University , Wuhan 430072, P.R. China.
Liangliang
L
Liu
Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, School of Physics, Communication and Electronics, Jiangxi Normal University , Nanchang 330022, Jiangxi, P.R. China.
Cailei
C
Yuan
Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, School of Physics, Communication and Electronics, Jiangxi Normal University , Nanchang 330022, Jiangxi, P.R. China.
Ting
T
Yu
Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, School of Physics, Communication and Electronics, Jiangxi Normal University , Nanchang 330022, Jiangxi, P.R. China.
Qinliang
Q
Li
Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, School of Physics, Communication and Electronics, Jiangxi Normal University , Nanchang 330022, Jiangxi, P.R. China.
Fanyan
F
Zeng
Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, School of Physics, Communication and Electronics, Jiangxi Normal University , Nanchang 330022, Jiangxi, P.R. China.
Gang
G
Gu
TiO2; crystal facet; gas sensing; hierarchical; hollow microspheres