Vulcan-Supported Pt Electrocatalysts for PEMFCs Prepared using Supercritical Carbon Dioxide Deposition

Bayrakceken, Ayse
Smirnova, Alevtina
Kitkamthorn, Usanee
Aindow, Mark
Tuerker, Lemi
Eroğlu, İnci
In this study, supercritical carbon dioxide (scCO(2)) deposition was used to prepare vulcan-supported Pt (Pt/Vulcan) electrocatalysts for proton exchange membrane fuel cells (PEMFCs), and the effects of process variables on the properties of the electrocatalysts were investigated. The two different methods used to reduce the organometallic precursor were thermal reduction in nitrogen at atmospheric pressure and thermal reduction in scCO(2). In the former method, the maximum Pt loading achieved was 9%, and this was governed by the adsorption isotherm of the Pt precursor between the scCO(2) phase and the Vulcan phase. By using the latter method, higher Pt loadings of 15% and 35% could be achieved. The Pt/Vulcan catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and cyclic voltammetry (CV). The average particle sizes for Pt/Vulcan 9%, 15%, and 35% catalysts were 1.2, 1.3, and 2nm, respectively. Electrochemical surface areas obtained from CV data were found to vary with the Pt loading.


DOGU, G; CABBAR, C; Doğu, Timur (Informa UK Limited, 1991-01-01)
The single-pellet moment techniques previously developed for the evaluation of effective diffusion coefficient and effective thermal conductivity of a porous solid are combined and a procedure is proposed for the simultaneous evaluation of these constants from a single set of pulse response experiments. It is shown that both temperature and concentration response curves can be measured from a single pulse of oxygen injected into hydrogen carrier gas flowing past a catalyst pellet. It is shown that the zerot...
Corrosion behaviours of Ti6Al4V-Mg/Mg-Alloy composites
ESEN, ZİYA; Ocala, Ezgi Butev; Akkaya, Asli; Gurcay, Bensu; Ozcan, Ceren; Ozgumus, Burcu Asli; Duygulu, Ozgur; Dericioğlu, Arcan Fehmi (Elsevier BV, 2020-04-15)
The effect of coupling of unalloyed Mg and Mg-alloys (AZ91 and WE43) with Ti6Al4V alloy on corrosion and degradation behaviours of produced composites has been investigated in simulated body fluid (SBF) by hydrogen evolution, and surface and electrochemical characterization techniques. Combining of unalloyed Mg with Ti6Al4V intensified galvanic corrosion and catastrophic failure occurred by initiation of microcracks formed by sudden hydrogen gas evolution. In contrast to other composites, Ti6Al4V-AZ91 compo...
Microwave-assisted simultaneous synthesis of conducting, non-conducting and cross-linked polymers from sodium 2,4,6-tribromophenolate and LiOH
Celik, Gueler Bayrakli; Kisakuerek, Duygu (Informa UK Limited, 2007-01-01)
Poly(dibromophenylene oxide) (P) and conducting polymer (CP) and/or cross-linked polymer (CLP) were synthesized simultaneously from sodium 2,4,6-tribromophenol ate and LiOH by microwave energy in a very short time interval. Polymerizations were carried out (i) under constant microwave energy and constant amount of water with different time intervals ranging from I to 20 min, or (ii) at constant time intervals and constant amount of water with variation of microwave energy ranging from 90 to 900 W, or (iii) ...
Kinetic analysis of DSC and thermogravimetric data on combustion of lignite
Kök, Mustafa Verşan (Springer Science and Business Media LLC, 1996-06-01)
Thermal analysis increasingly being used to obtain kinetic data relating to sample decomposition. This work involves a comparative study of several methods used to analyse DSC and TG/DTG data obtained on the oxidation of Beypazari lignite. A general computer program was developed and the methods are compared with regard to their accuracy and the ease of interpretation of the kinetics of thermal decomposition. For this study, the ratio method was regarded as the preferred method, because it permits the estim...
Phase transition of chemically synthesized FePt nanoparticles under high pressure
ŞİMŞEK, TELEM; Karci, Ozgur; ÖZCAN, ŞADAN (The Scientific and Technological Research Council of Turkey, 2018-01-01)
We present the results of a study related to phase transformation of chemically synthesized FePt nanoparticles under high pressure from face-centered cubic into face-centered tetragonal structure. As-synthesized nanoparticles are around 4.5 nm and show superparamagnetic behavior at 300 K. After annealing under 60 bar pressure of hydrogen at 400 degrees C for 2 h, nanoparticles exhibit strong ferromagnetic behavior with 5391 Oe coercivity. Results show that high-pressure annealing lowers the decomposition te...
Citation Formats
A. Bayrakceken et al., “Vulcan-Supported Pt Electrocatalysts for PEMFCs Prepared using Supercritical Carbon Dioxide Deposition,” CHEMICAL ENGINEERING COMMUNICATIONS, pp. 194–203, 2009, Accessed: 00, 2020. [Online]. Available: