Surface steps dominate the water formation on Pd(111) surfaces
Journal article, 2022

Water formation is relevant in many technological processes and is also an important model reaction. Although water formation over Pd surfaces is widely studied, questions regarding the active site and the main reaction path (OH* + OH*) or (OH* + H*) are still open. Combining first-principles density functional theory calculations and kinetic Monte Carlo simulations, we find that the reaction rate is dominated by surface steps and point defects over a wide range of conditions. The main reaction path is found to be temperature dependent where the OH* + OH* path dominates at low temperatures, whereas the OH* + H* path is the main path at high temperatures. Steps facilitate the OH* formation, which is the rate limiting step under all conditions. OH* is formed via O* + H* association or OOH* splitting at low temperatures, whereas OH* is exclusively formed via O* + H* association at high temperatures. The results of the first-principles-based kinetic model are in excellent agreement with experimental observations at high and low temperatures as well as different gas-phase compositions.

Author

Elisabeth Dietze

Chalmers, Physics, Chemical Physics

Lin Chen

Chalmers, Physics, Chemical Physics

Henrik Grönbeck

Chalmers, Physics, Chemical Physics

Journal of Chemical Physics

0021-9606 (ISSN) 1089-7690 (eISSN)

Vol. 156 6 064701

Subject Categories

Inorganic Chemistry

Other Chemical Engineering

DOI

10.1063/5.0078918

PubMed

35168342

More information

Latest update

2/24/2022