On-chip growth of patterned ZnO nanorod sensors with PdO decoration for enhancement of hydrogen-sensing performance
On-chip growth of patterned ZnO nanorod sensors with PdO decoration for enhancement of hydrogen-sensing performance
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DOI：
10.1016/j.ijhydene.2017.05.135
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发表时间：
2017-06-22
影响因子：
7.2
通讯作者：
Hugo Nguyen
中科院分区：
文献类型：
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作者：
Jiao, Mingzhi;Nguyen Van Duy;Hugo Nguyen
在这项研究中，我们使用了低温水热技术与ZnO纳米棒生长在芯片上的传感器阵列。然后用厚度为2、4和8 nm的Pd溅射装饰玻璃基板上的传感器，并在650 ℃下在空气中退火1小时。扫描电子显微镜、高分辨率透射显微镜、X射线衍射和X射线光电子能谱表征表明，ZnO纳米棒表面修饰了均匀的PdO纳米颗粒。传感器在350、400和450摄氏度下针对三种还原气体（即氢气、乙醇和氨气）进行了测试。用来自2和4 nm层的PdO颗粒装饰的ZnO纳米棒分别在450和350 ℃下对H-2表现出最高的响应。在相同浓度和所有测试温度下，这些样品通常对氢的选择性也比对乙醇和氨的选择性好。然而，ZnO纳米棒装饰与PdO颗粒从8 nm层显示出相反的传感行为相比，前两个。这些现象背后的传感机制进行了讨论，在光与PdO颗粒接触的氢的溢出效应，以及在溅射装饰，Pd-Zn异质结，在高温下形成的传感器电极之间形成的PdO薄膜的负竞争，从而影响ZnO纳米棒的导电性。(C)2017年氢能出版有限责任公司。由爱思唯尔有限公司出版。保留所有权利。
In this study, we used a low-temperature hydrothermal technique to fabricate arrays of sensors with ZnO nanorods grown on-chip. The sensors on the glass substrate then were sputter decorated with Pd at thicknesses of 2, 4, and 8 nm and annealed at 650 degrees C in air for an hour. Scanning electron microscopy, high resolution transmission microscopy, X-ray diffraction, and surface analysis by X-ray photoelectron spectroscopy characterization demonstrated that decoration of homogenous PdO nanoparticles on the surface of ZnO nanorods had been achieved. The sensors were tested against three reducing gases, namely hydrogen, ethanol, and ammonia, at 350, 400, and 450 degrees C. The ZnO nanorods decorated with PdO particles from the 2 and 4 nm layers showed the highest responses to H-2 at 450 and 350 degrees C, respectively. These samples also generally exhibited better selectivity for hydrogen than for ethanol and ammonia at the same concentrations and at all tested temperatures. However, the ZnO nanorods decorated with PdO particles from the 8 nm layer showed a reverse sensing behaviour compared with the first two. The sensing mechanism behind these phenomena is discussed in the light of the spillover effect of hydrogen in contact with the PdO particles as well as the negative competition of the PdO thin film formed between the sensor electrodes during sputter decoration, Pd-Zn heterojunction that forms at high temperature and thus influences the conductivity of the ZnO nanorods. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.