Kinetics of NH₃ Desorption and Diffusion on Pt: Implications for the Ostwald Process.

ABSTRACT: We report accurate time-resolved measurements of NH₃ desorption from Pt(111) and Pt(332) and use these results to determine elementary rate constants for desorption from steps, from (111) terrace sites and for diffusion on (111) terraces. Modeling the extracted rate constants with transition state theory, we find that conventional models for partition functions, which rely on uncoupled degrees of freedom (DOFs), are not able to reproduce the experimental observations. The results can be reproduced using a more sophisticated partition function, which couples DOFs that are most sensitive to NH₃ translation parallel to the surface; this approach yields accurate values for the NH₃ binding energy to Pt(111) (1.13 ± 0.02 eV) and the diffusion barrier (0.71 ± 0.04

SUBMITTER: Borodin D 

PROVIDER: S-EPMC8569812 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature