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Platinum nanoparticle shape effects on benzene hydrogenation selectivity
Kaitlin M Bratlie1, Hyunjoo Lee, Kyriakos Komvopoulos
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Nano Letters
|September 20, 2007
Summary
Platinum nanoparticle shape dictates benzene hydrogenation selectivity. Cubic nanoparticles yield only cyclohexane, while cuboctahedral ones produce both cyclohexane and cyclohexene, offering insights into catalytic processes.
Area of Science:
- Heterogeneous catalysis
- Surface science
- Nanoparticle engineering
Background:
- Benzene hydrogenation is a key industrial process.
- Platinum (Pt) is a crucial catalyst for this reaction.
- Understanding the role of catalyst morphology and surface modifiers is essential for optimizing selectivity and activity.
Purpose of the Study:
- To investigate the effect of platinum nanoparticle shape on benzene hydrogenation.
- To elucidate the role of tetradecyltrimethylammonium bromide (TTAB) as a surface modifier.
- To compare catalytic performance of shaped nanoparticles with single-crystal surfaces.
Main Methods:
- Synthesis of cubic and cuboctahedral platinum nanoparticles.
- Adsorption studies using infrared (IR) spectroscopy to characterize TTAB binding.
- Benzene hydrogenation reaction kinetics and product selectivity analysis.
- Determination of apparent activation energies for product formation.
Main Results:
- Tetradecyltrimethylammonium bromide (TTAB) weakly binds to the Pt surface via C-H...Pt interactions.
- Nanoparticle shape significantly influences catalytic selectivity: cubic Pt yields only cyclohexane, while cuboctahedral Pt produces both cyclohexane and cyclohexene.
- Lower apparent activation energies and higher turnover rates were observed for nanoparticles compared to single-crystal Pt surfaces.
Conclusions:
- Platinum nanoparticle shape is a critical factor controlling selectivity in benzene hydrogenation.
- The observed selectivity trends align with those previously reported for Pt(111) and Pt(100) single crystals.
- Shaped platinum nanoparticles offer enhanced catalytic performance over traditional single-crystal surfaces.
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