Enhanced Ethanol Gas Sensing Properties of SnO2-Core/ZnO-Shell Nanostructures

Sensors

T. Tharsika²  A. S. M. A. Haseeb²  Sheikh A. Akbar¹  Mohd Faizul Mohd Sabri² 

[1]Center for Industrial Sensors and Measurements (CISM), Department of Materials Science and Engineering, Ohio State University, 2041 College Road, Columbus, OH 43210, USA

[2] E-Mail:

[3]Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia

[4] E-Mails:

关键词: ethanol gas sensor;    ZnO;    SnO₂;    core-shell nanostructures;    hierarchical nanostructures;   

DOI  :  10.3390/s140814586

来源: mdpi

【 摘 要 】

An inexpensive single-step carbon-assisted thermal evaporation method for the growth of SnO₂-core/ZnO-shell nanostructures is described, and the ethanol sensing properties are presented. The structure and phases of the grown nanostructures are investigated by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. XRD analysis indicates that the core-shell nanostructures have good crystallinity. At a lower growth duration of 15 min, only SnO₂ nanowires with a rectangular cross-section are observed, while the ZnO shell is observed when the growth time is increased to 30 min. Core-shell hierarchical nanostructures are present for a growth time exceeding 60 min. The growth mechanism for SnO₂-core/ZnO-shell nanowires and hierarchical nanostructures are also discussed. The sensitivity of the synthesized SnO₂-core/ZnO-shell nanostructures towards ethanol sensing is investigated. Results show that the SnO₂-core/ZnO-shell nanostructures deposited at 90 min exhibit enhanced sensitivity to ethanol. The sensitivity of SnO₂-core/ZnO-shell nanostructures towards 20 ppm ethanol gas at 400 °C is about ∼5-times that of SnO₂ nanowires. This improvement in ethanol gas response is attributed to high active sensing sites and the synergistic effect of the encapsulation of SnO₂ by ZnO nanostructures.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.