Porous ZnO Polygonal Nanoflakes: Synthesis, Use in High-Sensitivity NO2 Gas Sensor, and Proposed Mechanism of Gas Sensing

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• 作者：Mei Chen ; Zhihua Wang ; Dongmei Han ; Fubo Gu ; Guangsheng Guo
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：July 7, 2011
• 年：2011
• 卷：115
• 期：26
• 页码：12763-12773
• 全文大小：1396K
• 年卷期：v.115,no.26(July 7, 2011)
• ISSN：1932-7455

文摘

Unique porous ZnO polygonal nanoflakes were synthesized by the microwave hydrothermal method. The structural properties of the products were investigated by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), and high-resolution TEM techniques. In situ diffuse reflectance infrared Fourier transform spectroscopy technique was employed to investigate the mechanism of NO₂ sensing. Free nitrate ions, nitrate ions, and nitrite anions were the main adsorbed species. N₂O was formed via NO^{鈥?/sup> and N₂O₂鈥?/sup> that were stemmed from NO. Comparative tests for gas sensing between gas sensors based on the as-prepared porous ZnO nanoflakes and purchased ZnO nanoparticles clearly showed that the former exhibited more excellent NO₂ sensing performances. Photoluminescence and X-ray photoelectron spectroscopy spectra further proved that the intensities of donors (oxygen vacancy (V_O) and/or zinc interstitial (Zn_i)) and surface oxygen species (O₂鈥?/sup> and O₂), which were involved in the mechanism of gas sensing led to the different gas-sensing properties.}