Novel recirculating loop reactor for studies on model catalysts: CO oxidation on Pt/TiO2(110)

Area of Science:

• Surface Science
• Chemical Kinetics
• Catalysis

Background:

• Evaluating kinetics of model catalysts with few active sites is challenging.
• Ultrahigh vacuum (UHV) surface science techniques require high sensitivity for kinetic measurements.
• Conventional methods struggle with low active site densities on model single-crystal surfaces.

Purpose of the Study:

• To develop and validate a novel recirculating loop microreactor coupled to a UHV chamber.
• To achieve sensitive kinetic evaluation of model catalysts.
• To enable detailed characterization using UHV surface science techniques.

Main Methods:

• Construction of a microreactor with minimized dead volume (32 cm³).
• Operation in recirculation mode with computer-controlled automated switching valves.
• Gas chromatography for product analysis and kinetic parameter determination.

Main Results:

• Successful proof-of-principle study of CO oxidation on Pt clusters/TiO2(110) single crystal.
• Kinetic parameters comparable to literature values for similar catalytic systems.
• Calculated activation energy: 16.4 ± 0.7 kcal/mol; Turnover frequency: 0.03-0.06 molecules/(site·s); Reaction orders (O2, CO): 0.9 ± 0.2, -0.82 ± 0.03.

Conclusions:

• The novel microreactor system provides sufficient sensitivity for kinetic studies on model catalysts.
• The system allows for extended kinetic measurements (up to 24 hours) with high precision.
• This approach facilitates the integration of surface science characterization with kinetic analysis.