Synthesis and enhanced NO₂ gas sensing properties of ZnO nanorods/TiO₂ nanoparticles heterojunction composites

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• 作者：C.W. Zou ; ^{qingyihaiyanas@163.com" class="auth_mail" title="E-mail the corresponding author} ; J. Wang ; W. Xie
• 关键词：ZnO nanorods ; TiO2 nanoparticles ; NO2 gas sensing ; Heterojunction
• 刊名：Journal of Colloid and Interface Science
• 出版年：2016
• 出版时间：15 September 2016
• 年：2016
• 卷：478
• 期：Complete
• 页码：22-28
• 全文大小：2172 K

文摘

ZnO nanorods/TiO₂ nanoparticles composites were synthesized and the effects of TiO₂ concentrations on the NO₂ sensing properties were studied in detail. The as-prepared composites were characterized by XRD, SEM, TEM, PL, I-V and gas sensing measurements. The gas sensing results demonstrated that all the sensors based on ZnO/TiO₂ nanocomposites exhibited much higher response than that of sensors based on pure ZnO nanorods. At the optimum operating temperature of 180 °C, the response values of the sensors based on ZnO/TiO₂ nanocomposites decorated with TiO₂ concentrations of 0, 3, 5, 8 and 10 wt% were 50, 140, 310, 350 and 258, respectively. The PL and I-V results indicated that the increased charge transfer between the ZnO nanorods mediated by TiO₂ nanoparticles enhanced the conductivity of the ZnO/TiO₂ nanocomposites. The gas sensing mechanism was also carefully analyzed. The attachment of TiO₂ nanoparticles onto ZnO nanorods induced more active sites for the adsorption of oxygen molecules (O²) and O² which can be more easily adsorbed on the surface of ZnO nanorods. Furthermore, the conduction channel of ZnO/TiO₂ was much narrower as a result of the formation of heterojunction which may further contribute to the enhanced NO₂ sensing properties.