Coverage dependence of CO surface diffusion on Pt nanoparticles: An EC-NMR study

P. K. Babu, T. Kobayashi, H. Chung, Eric Oldfield, Andrzej Wieckowski

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have studied the effects of CO coverage on surface diffusion rates of CO adsorbed on nanoparticle Pt catalysts in sulfuric acid media by using 13C EC-NMR at 253 - 293 K. For CO coverage from 1.0 to 0.36, the diffusion coefficients follow Arrhenius behavior and both activation energy (Ed) and pre-exponential factor (DCO) show CO coverage dependence. When the coverage is increased from 0.36 to 1.0, Ed increases from 6.0 to 8.4 kcal/mol and DCO from 1.1 × 10-8 to 3.7 × 10-6 cm2/s. At partial CO coverage, our data support the free site hopping model of adsorbed CO as the major surface diffusion mechanism. When the diffusion coefficient was estimated from CO stripping measurements by using an electrochemical modeling protocol, the diffusion coefficients were a few orders of magnitude larger than those obtained from the EC-NMR experiments. Overall these results are important for improving our understanding of electrochemical surface dynamics that play a crucial role in controlling fuel cell reaction rates.

Original languageEnglish (US)
Title of host publication233rd ACS National Meeting, Abstracts of Scientific Papers
StatePublished - Dec 28 2007
Event233rd ACS National Meeting - Chicago, IL, United States
Duration: Mar 25 2007Mar 29 2007

Publication series

NameACS National Meeting Book of Abstracts
ISSN (Print)0065-7727

Other

Other233rd ACS National Meeting
CountryUnited States
CityChicago, IL
Period3/25/073/29/07

    Fingerprint

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

Cite this

Babu, P. K., Kobayashi, T., Chung, H., Oldfield, E., & Wieckowski, A. (2007). Coverage dependence of CO surface diffusion on Pt nanoparticles: An EC-NMR study. In 233rd ACS National Meeting, Abstracts of Scientific Papers (ACS National Meeting Book of Abstracts).