Browsing by Author "Yurtcan, Ayse Bayrakceken"

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A Novel Central Composite Design Based Response Surface Methodology Optimization Study for the Synthesis of Pd/Cnt Direct Formic Acid Fuel Cell Anode Catalyst
(Pergamon-elsevier Science Ltd, 2018) Caglar, Aykut; Sahan, Tekin; Cogenli, M. Selim; Yurtcan, Ayse Bayrakceken; Aktas, Nahit; Kivrak, Hilal
At present, carbon nanotube supported Pd catalysts are synthesized via NaBH4 reduction method to investigate their electro catalytic activity thorough formic acid electro oxidation. In order to optimize the synthesis conditions such as %Pd amount (X-1), NaBH4 amount (times, X-2), water amount (ml, X-3), and time (min., X-4), Central Composite Design (CCD) experiments are designed and determined by the Design-Expert program to determine the maximum observed current (mA/mgPd). Formic acid electro oxidation current density of the catalyst is computed by the model as 974.80 mA/mg Pd for the catalyst prepared at optimum operating conditions (41.14 for %Pd amount, 280.23 NaBH4 amount, 26.80 ml water amount, and 167.14 min time) obtained with numerical optimization method in CCD. This computed value is very close to the experimentally measured value as 920 mA/mg Pd. Finally, formic acid fuel cell measurements were performed on the Pd/CNT catalyst prepared at optimum operating conditions and compared with the commercial Pd black and Pt black catalysts. As a result, Pd/CNT exhibits better performance compared to Pd black, revealing that Pd/CNT is a promising catalyst for the direct formic acid fuel cell measurements. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Remarkable Activity of a Znpdpt Anode Catalyst: Synthesis, Characterization, and Formic Acid Fuel Cell Performance
(Pergamon-elsevier Science Ltd, 2021) Caglar, Aykut; Cogenli, Mehmet Selim; Yurtcan, Ayse Bayrakceken; Alal, Orhan; Kivrak, Hilal
Herein, multi-walled carbon nanotube (MWCNT) supported Zn-Pd and Zn-Pd-Pt catalysts have been prepared utilizing a sequential sodium borohydride (SBH) reduction method. The resulting Zn/MWCNT, Zn-Pd/MWCNT, and Zn-Pd-Pt/MWCNT catalysts were characterized using advanced surface analytical techniques such as X-ray diffraction (XRD), high contrast transmission electron microscopy (C-TEM), and X-ray photoelectron spectroscopy (XPS). The characterization results indicate that the Zn/MWCNT, Zn-Pd/MWCNT, and Zn-Pd-Pt/MWCNT catalysts were successfully prepared. It was observed that Pd and Pt incorporation into Zn alters the electronic structure of Zn. Cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) were used to examine the electrochemical activity of the catalysts toward the electrooxidation of formic acid (FA). The results reveal that ZnPdPt/MWCNT has a specific activity of 12.6 mA/cm(2) and an electrochemical active surface area (ECSA) of 41.1 m(2)/g. This catalyst shows high activity, stability, and resistance when compared to Pd/MWCNT and ZnPd/MWCNT. Direct FA fuel cell (DFAFC) measurements were performed at 18-60 degrees C for the ZnPd/MWCNT and ZnPdPt/MWCNT catalysts. The specific activity of ZnPdPt/MWCNT was 1.45 times greater than that measured for ZnPd/MWCNT. ZnPdPt/MWCNT is a promising catalyst according to our CV, CA, EIS, and DFAFC measurements.