| Attributs | Valeurs |
|---|
| type
| |
| Is Part Of
| |
| Subject
| |
| Title
| - Hydrogen Oxidation Reaction on Pt in Acidic Media: Adsorption Isotherm andActivation Free Energies
|
| has manifestation of work
| |
| related by
| |
| Author
| |
| Abstract
| - We present a method for quantifying the kinetic current of the hydrogen oxidation reaction (HOR) on Pt inacidic media using the adsorption and activation free energies as the intrinsic kinetic parameters. Our approachinvolves deriving the HOR intermediate's adsorption isotherm based on the same dual-pathway reaction modelas for the kinetic equation. Coupled with density functional theory calculations of the coverage- and site-dependent hydrogen dissociation free energies, we analyzed the adsorption isotherms for H on atop (HAtop)sites and in hollow/bridge (HH/B) sites obtained respectively from infrared spectroscopic and electrochemicalmeasurements. Although the hydrogen dissociative adsorption energy is not site-sensitive on Pt, HAtop has anorder of magnitude lower coverage and higher activity than HH/B. We attributed this distinction to their differententropies; HH/B is less accessible to water than HAtop, and the formation of a hydrogen bond is essential in theoxidative generation of H3O+. Using volcano plots, we illustrated possible ways that the exchange currentmay vary with the adsorption free energy and discussed the factors that contributed to the exceptionally highactivity of Pt for the HOR.
|
| article type
| |
| is part of this journal
| |
