Interactions between co-adsorbed CO and H on a Rh(100) single crystal surface

Area of Science:

• Surface Science
• Materials Chemistry
• Catalysis

Background:

• Understanding co-adsorption is crucial for catalytic processes.
• Rh(100) is a model catalyst surface for reactions involving CO and H2.

Purpose of the Study:

• To investigate the co-adsorption behavior of CO and H2 on Rh(100).
• To determine the resulting surface structure and its effect on desorption temperatures.

Main Methods:

• Temperature Programmed Desorption (TPD)
• Reflection Absorption Infrared Spectroscopy (RAIRS)
• Low Energy Electron Diffraction (LEED)
• Density Functional Theory (DFT) calculations

Main Results:

• Co-exposure formed a c(3√2×√2)R45° structure with 0.67 ML CO and 0.67 ML H.
• CO occupied bridge sites; H occupied surface bridge and subsurface octahedral sites.
• Hydrogen desorbed around 230 K due to CO co-adsorption.

Conclusions:

• CO co-adsorption induces displacement of H and formation of specific surface/subsurface sites.
• The observed H desorption behavior is directly linked to the co-adsorbed CO structure.