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The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Is the methanation reaction over Ru single crystals structure dependent?
Søren B Vendelbo1, Martin Johansson, Jane H Nielsen
1Center for Individual Nanoparticle Functionality, Department of Physics, Technical University of Denmark, Building 312, 2800 Kgs. Lyngby, Denmark.
Physical Chemistry Chemical Physics : PCCP
|January 25, 2011
Summary
Methanation on ruthenium is highly structure-dependent. Undercoordinated sites like steps and kinks are crucial for this reaction, as demonstrated by sulfur poisoning and sputtering experiments.
Area of Science:
- Catalysis
- Surface Science
- Chemical Engineering
Background:
- The methanation reaction is vital for producing methane, a key energy source.
- Understanding the role of surface structure in catalytic reactions is essential for catalyst design.
- Ruthenium is a known catalyst for methanation, but structure-activity relationships require further elucidation.
Purpose of the Study:
- To investigate the influence of monoatomic steps and defects on the methanation reaction over ruthenium.
- To correlate local surface reactivity with global reactivity on a single crystal catalyst.
- To determine the specific active sites for methanation on ruthenium surfaces.
Main Methods:
- Experiments were conducted on a Ru(0154) ruthenium single crystal with defined monoatomic steps.
- Methanation activity was measured at one bar of hydrogen and CO in a high-pressure cell.
- Local and global reactivity were measured simultaneously, with and without sulfur poisoning and sputtering.
Main Results:
- Sulfur poisoning affected the stepped surface faster than the entire crystal, indicating steps are more reactive.
- Increased sputtering of the stepped surface enhanced its reactivity.
- The methanation reaction rate was significantly influenced by surface structure, particularly undercoordinated sites.
Conclusions:
- The methanation reaction over ruthenium predominantly occurs on undercoordinated sites, such as steps and kinks.
- The reaction is extremely structure-dependent, highlighting the importance of surface topography.
- Catalyst design for methanation should focus on creating or preserving specific undercoordinated sites.
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