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Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics
Published on: April 12, 2019
A density functional theory study of sulfur poisoning
1School of Chemistry, The Queen's University of Belfast, Belfast BT9 5AG, N. Ireland, United Kingdom.
The Journal of Chemical Physics
|April 20, 2005
Summary
Sulfur strongly adsorbs and hinders reactions on Rhodium (Rh) surfaces, especially at step sites, explaining sulfur poisoning. Hydrogenation of sulfur is difficult compared to carbon, nitrogen, or oxygen on Rh(211).
Area of Science:
- Surface Science
- Computational Chemistry
- Materials Science
Background:
- Sulfur poisoning is a critical issue in catalysis, particularly on transition metal surfaces like Rhodium.
- Understanding the interaction of sulfur with metal surfaces is essential for designing more robust catalysts.
Purpose of the Study:
- To investigate the chemisorption and hydrogenation of sulfur-containing species on a stepped Rh(211) surface.
- To elucidate the mechanism of sulfur poisoning and compare it with other adsorbates like C, N, and O.
Main Methods:
- Density Functional Theory (DFT) calculations were employed to study adsorption energies and reaction pathways.
- Transition states for hydrogenation reactions were identified on the Rh(211) stepped surface.
Main Results:
- Chemisorption of H, S, SH, and H2S on Rh(211) was investigated.
- The hydrogenation of S to H2S involves two steps with distinct transition state configurations.
- Sulfur hydrogenation was found to have significantly higher energy barriers compared to C, N, and O hydrogenation on Rh(211).
Conclusions:
- Sulfur atoms and related species strongly adsorb and poison defect sites like steps on Rh surfaces.
- The high barriers for sulfur hydrogenation explain its persistent poisoning effect, unlike C, N, and O.
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