Atomic oxygen recombination on quartz at high temperature: experiments and molecular dynamics simulation

Area of Science:

• Surface Science
• Chemical Kinetics
• Materials Science

Background:

• Atomic oxygen recombination is crucial for atmospheric chemistry and catalysis.
• Understanding surface interactions is key to controlling chemical reactions.
• Beta-quartz is a relevant material in various industrial and scientific applications.

Purpose of the Study:

• To experimentally measure the atomic oxygen recombination coefficient on a beta-quartz surface.
• To theoretically investigate the surface catalytic activity and recombination mechanism.
• To compare experimental findings with theoretical predictions and understand surface effects.

Main Methods:

• Utilized the MESOX setup for direct measurement of the recombination coefficient (gamma) at 1000 K.
• Employed visible spectroscopy to determine atomic oxygen concentration profiles.
• Performed semiclassical collision dynamics calculations for theoretical analysis.

Main Results:

• Obtained an experimental recombination coefficient gamma = 0.008 for beta-quartz.
• Found the beta-quartz gamma value to be approximately three times lower than that for beta-cristobalite.
• Achieved qualitative and quantitative agreement between experimental and theoretical results.

Conclusions:

• The Eley-Rideal recombination mechanism is supported for oxygen atoms on beta-quartz.
• Surface crystallographic variations significantly impact catalytic activity.
• The study provides insights into the energetics and mechanisms of surface processes involving oxygen atoms.