Activation energies for oxygen reduction on platinum alloys: theory and experiment.
A combined theoretical and experimental analysis of the electrode potential dependencies of activation energies is presented for the first step in oxygen reduction over platinum and platinum alloy catalysts in both polycrystalline and carbon supported form. Tafel data for several of the catalysts are used to predict potential-dependent activation energies for oxygen reduction over the 0.6-0.9 V range in strong and weak acid. Comparisons with the theoretical curve show good agreement above 0.8 V, suggesting a fairly constant preexponential factor. Arrhenius determinations of activation energies over the 0.7-0.9 V range yield little trend for weak acid, possibly because of the larger uncertainties in the Arrhenius fits, but the strong acid results have smaller uncertainties and for them the measured activation energies trend up with potential.
Anderson
Alfred B
AB
Chemistry Department, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106-7078, USA. aba@po.cwru.edu
Roques
Jérôme
J
Mukerjee
Sanjeev
S
Murthi
Vivek S
VS
Markovic
Nenad M
NM
Stamenkovic
Vojislav
V
D000497:Alloys / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D004566:Electrodes; D006860:Hydrogen Bonding; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D013499:Surface Properties
D000497:Alloys; D010984:Platinum; D002244:Carbon; D010100:Oxygen