5 - Max-Planck-Institut für Kohlenforschung

40
PtCl 4 + Vulcan (carbon black)
Synthetic Organic Chemistry - M. T. Reetz
H 2O
HO
PtO x on Vulcan
(1.8 nm)
reduction
We then made the surprising discovery that the type of carbon black has a profound
influence on the electrocatalytic activity of the solid catalyst (following electrochemical
reduction). Upon substituting the conventional Vulcan XC72 by another carbon black
usually used in ink jet technology, Printex XE2, a 34% enhancement of electrocatalytic
activity (oxygen reduction) was observed! Moreover, upon performing multiple
potential scans between 0.05 and 1.2 V (NHE) in cyclic voltammograms, the
electrochemically accessible Pt area was determined from the hydrogen adsorption QH.
It is much larger in the case of the Printex-based electrocatalyst. The particle size d was
also determined by CV: 3.9 nm for Printex and 9.5 nm for Vulcan. In agreement with
this analysis, HRTEM studies revealed that Pt-particles agglomerate in the case of the
traditional Vulcan material, whereas little undesired Pt-particle growth occurs on the
Printex support (see report by B. Tesche).
Current / mA
0,2
0,1
0,0
-0,1
-0,2
-0,3
Pt/Printex XE2
Pt/Vulcan XC72 (ETEK)
0,0 0,2 0,4 0,6 0,8 1,0 1,2
Potential (NHE) / V
Publications resulting from this research area: 94, 97, 108, 264, 284, 397, 409
External funding: Katalyseverbund Nordrhein-Westfalen; NaKaB (Network of five
research groups in NRW and one in Saarland dedicated to research in the area of fuel
cells)
Cooperations: B. Tesche (Mülheim/Ruhr, DE); R. Kirchheim (Göttingen, DE);
W. Grünert (Bochum, DE); W. Vogel (Berlin, DE); members of NaKaB: J. W. Schultze
(Düsseldorf, DE), F. Mahlendorf (Duisburg, DE), J. Divisek, D. Stolten (FZ Jülich,
DE), H. Baltruschat (Bonn, DE), R. Hempelmann (Saarbrücken, DE)
Pt/C