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Rh-promoted methanol decomposition on cerium oxide thin films
1Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6201, USA.
The Journal of Physical Chemistry. B
|August 11, 2006
Summary
Rhodium nanoparticles on cerium oxide promote methanol decomposition to CO and H. The metal-oxide interface is key for methoxy intermediate breakdown, with reduced ceria enhancing total decomposition.
Area of Science:
- Surface science
- Heterogeneous catalysis
- Materials science
Background:
- Methanol is a key chemical feedstock.
- Understanding its surface reactions is crucial for catalysis.
- Cerium oxide (ceria) and rhodium are important catalytic materials.
Purpose of the Study:
- Investigate methanol adsorption and reaction on Rh-loaded ceria.
- Determine the role of ceria oxidation state and Rh properties.
- Elucidate reaction pathways and intermediates.
Main Methods:
- Ultra-high vacuum (UHV) studies.
- Temperature-programmed desorption (TPD).
- Synchrotron soft X-ray photoelectron spectroscopy (SXPS).
Main Results:
- Methanol decomposes to CO and H on Rh below 200 K.
- CO evolves from Rh on oxidized ceria (400–500 K).
- Reduced ceria leads to CO decomposition to atomic C on Rh.
- Methoxy is the primary intermediate on ceria, decomposing to CO and H2.
- Rhodium suppresses formaldehyde formation and promotes methoxy decomposition at interfaces.
- Reduced ceria enhances overall methanol decomposition.
Conclusions:
- Rhodium significantly alters methanol reaction pathways on ceria.
- Metal-oxide interfaces are critical for methoxy decomposition.
- Ceria's oxidation state modulates the extent of methanol decomposition.
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