Pathways for H2 Activation on (Ni)-MoS2 Catalysts.
Eva Schachtl1, Elena Kondratieva1, Oliver Y Gutiérrez1
1Department of Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
The Journal of Physical Chemistry Letters
|August 13, 2015
Summary
Nickel-promoted molybdenum disulfide (NiMoS2/Al2O3) enhances surface hydrogen concentration by activating hydrogen (H2) and hydrogen sulfide (H2S) chemisorption sites, increasing active surface hydrogen by 30%.
Area of Science:
- Catalysis
- Surface Chemistry
- Materials Science
Background:
- Molybdenum disulfide (MoS2) is a key catalyst in hydrodesulfurization.
- Understanding the role of promoters like Nickel (Ni) is crucial for optimizing catalyst performance.
Purpose of the Study:
- To investigate the activation mechanism of H2 and H2S on NiMoS2/Al2O3.
- To quantify the effect of Ni loading on active surface hydrogen concentration.
Main Methods:
- Adsorption studies of H2 and H2S on NiMoS2/Al2O3.
- Titration of surface acid sites using 2,6-dimethylpyridine.
- H2-D2 isotopic exchange experiments.
Main Results:
- Activation of H2 and H2S forms acidic SH groups on NiMoS2/Al2O3.
- Both H2 and H2S dissociate on coordinatively unsaturated cations and neighboring S(2-) sites.
- Optimal Ni loading increases active surface hydrogen concentration by up to 30%.
Conclusions:
- Nickel promotes the formation of active surface hydrogen by enhancing H2 and H2S chemisorption.
- The study elucidates the role of sulfur vacancies and SH groups in the catalytic mechanism.
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