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    Electrochemical Growth of Pd Doped ZnO Nanorods
    (ELECTROCHEMICAL SOC INC, 2015) Kosemen, Arif; Kosemen, Zuhal Alpaslan; Ozturk, Sadullah; Kilinc, Necmettin; San, Sait Eren; Tunc, Ali Veysel
    In this work, dense arrays of pure and Pd doped zinc oxide (ZnO) nanorods (NRs) were fabricated by an electrochemical growth. Pure and Pd doped ZnO NRs were characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and optic spectroscopy. Structural studies confirmed that pure and doped ZnO NRs present the hexagonal wurtzite crystal structures. The optical properties of pure and doped ZnO NRs were found to present redshift by increasing doping concentration. The diameters of the NRs increase with increasing Pd doping concentration under same condition. Compared with pure ZnO NRs, the Pd doped ZnO NRs presents improved optical properties in terms of bandgap energy from 3.24 eV to 1.97 eV. These bandgap values were obtained by optical absorption using a UV-Visible spectrophotometer. In addition, Pd doping concentration in ZnO affects the active species on the surface such as oxygen deficiencies and hydroxyls. The electrochemically growing mechanism is also discussed in detail in the scope of this work. (C) 2015 The Electrochemical Society. All rights reserved.
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    Electrochemically growth of Pd doped ZnO nanorods on QCM for room temperature VOC sensors
    (ELSEVIER SCIENCE SA, 2016) Ozturk, Sadullah; Kosemen, Arif; Kosemen, Zuhal Alpaslan; Kilinc, Necmettin; Ozturk, Zafer Ziya; Penza, Michele
    Pristine and various palladium (Pd) doped ZnO nanorods have been synthesized on the quartz crystal microbalance (QCM) for volatile organic compound (VOCs) sensors at room temperature. The doping concentrations were varied from 0 mol% to 2.5 mol% by using electrochemical deposition method. The diameters of the fabricated nanorods were in the range of 100-200nm, and were increased with Pd doping. The tested VOCs included alcohols (ethanol, methanol, isopropyl), ester (ethyl acetate), aromatic (toluene, xylene), ketone (acetone) and chloroform in the different concentrations. The results indicated that the sensitivity of the sensing materials was enhanced with the increasing Pd doping concentrations except for the acetone and chloroform. The undoped ZnO nanorod sensor showed higher sensor response against to acetone and chloroform while exposing high concentration of two analytes due to the absorbing/adsorbing mechanism. All undoped and Pd doped nanorods sensors showed the highest sensitivity to xylene. (C) 2015 Elsevier B.V. All rights reserved.