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International audience; The existence of asymmetry in X-ray photoelectron spectroscopy (XPS) photoemission lines is widely accepted, but line shapes designed to accommodate asymmetry are generally lacking in theoretical justification. In this work, we present a new line shape for describing asymmetry in XPS signals that is based on two facts. First, the most widely known line shape for fitting asymmetric XPS signals that has a theoretical basis, referred to as the Doniach-Sunjic (DS) line shape, suffers from a mathematical inconvenience, which is that for asymmetric shapes the area beneath the curve (above the x-axis) is infinite. Second, it is common practice in XPS to remove the inelastically scattered background response of a peak in question with the Shirley algorithm. The new line shape described herein attempts to retain the theoretical virtues of the DS line shape, while allowing the use of a Shirley background, with the consequence that the resulting line shape has a finite area. To illustrate the use of this Doniach-Sunjic-Shirley (DSS) line shape, a set of spectra obtained from varying amounts of graphene oxide (GO) and reduced GO on a patterned, heterogeneous surface are fit and discussed.

The glucose oxidation reaction (GOR) is strictly controlled by the surface structure of an electrode. Here, we report the effect of potentiostatic deposition (PSD), potentiocyclic deposition (PCD), and a combination of these two modes (PSD/PCD) for platinum deposition on a carbon-based substrate as an electrocatalyst for an alkaline GOR. An optimized electrode results in current density of 18 mA cm−2 at −0.3 V, open circuit potential of −0.85 V, exchange current density of 2.11 mA cm−2, charge transfer resistance of 89.01 Ω cm−2 and a low diffusive behavior toward GOR. The total Pt loadings for these electrodes are PCD > PSD > PSD/PCD, while the Pt quantity on top of the electrode surface is PSD/PCD > PCD > PSD. These results illustrate that applying PSD prior to PCD reduces Pt loading, helps the formation of Pt particles at the top surface, and thus leads to better electrocatalytic activity toward GOR.

There are several methods to prepare electro-catalysts for low temperature fuel cells. Platinum is used as a common electro-catalyst for this purpose. Electrodeposition method is applied for preparing platinum on modified carbon paper as electrode directly. Many parameters effect on performance of prepared electrodes. At this work, the effect of type of electrolyte in electrodeposition solution was investigated for making electro-catalyst that is be used as anode in Glucose Alkaline Air Fuel Cell (GAAFC). Cyclic voltammetry ((1.2-0.6) V vs. Ag/AgCl sat. KCl, 100 mV/S) is used as electrodeposition method. Number of CV cycles is varied 10 to 50. Electrodeposition was performed in two precursor solution (0.5 M) containing phosphate and sulfate anions. Platinum concentration in solution was 3 mM. The prepared electro-catalysts were studied for Glucose Oxidation Reaction (GOR) by CV analysis in 0.3 M glucose solution and 0.5 M KOH. Also, Electrochemical Impedance Spectroscopy (EIS) method was used. According our results, the type of anion in electrodeposition solution affects on properties of prepared platinum electro-catalyst for GOR. Optimized condition for number of CV cycles in phosphate and sulfate solutions is 10 and 40 respectively. Article DOI: https://dx.doi.org/10.20319/mijst.2016.s11.91102 This work is licensed under the Creative Commons Attribution-Non-commercial 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.