Cooperative adsorbate binding catalyzes high-temperature hydrogen oxidation on palladium
Michael Schwarzer1,2, Dmitriy Borodin1,2, Yingqi Wang3
1Institute for Physical Chemistry, University of Göttingen, 37077 Göttingen, Germany.
Science (New York, N.Y.)
|October 31, 2024
Summary
Heterogeneous catalysts accelerate reactions via atomic structures formed at high temperatures. On palladium, three oxygen atoms at steps cooperatively form a highly reactive configuration for hydrogen oxidation.
Area of Science:
- Surface science
- Chemical kinetics
- Catalysis
Background:
- Atomic-scale structures crucial for heterogeneous catalysis are often unstable under ambient conditions.
- Observing these active sites requires specialized techniques beyond low-temperature, ultra-high-vacuum methods.
Purpose of the Study:
- To investigate the atomic-scale mechanisms of catalytic hydrogen oxidation on palladium at high temperatures.
- To correlate reaction rates with specific surface configurations and densities.
Main Methods:
- Velocity-resolved kinetics measurements at high temperatures and pressures.
- Development of a kinetic model integrating density functional theory and transition-state theory.
Main Results:
- Reaction rates showed complex dependencies on oxygen coverage and step density.
- A cooperatively stabilized configuration of three oxygen atoms at steps was identified as the key active site.
- This multi-atom configuration significantly enhances reactivity compared to isolated atoms.
Conclusions:
- The study reveals a novel mechanism for reactivity enhancement in heterogeneous catalysis.
- Cooperative stabilization of active sites is critical for efficient catalytic processes.
- Palladium-catalyzed hydrogen oxidation serves as a prime example of dynamic, high-reactivity site formation.
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