Remarkable NO oxidation on single supported platinum atoms
Chaitanya K Narula1, Lawrence F Allard1, G M Stocks1
1Materials Science &Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6133.
Scientific Reports
|November 29, 2014
Summary
Single platinum atoms on oxidized alumina exhibit high NO oxidation activity, contrary to expectations for smaller particles. This finding reveals that isolated platinum atoms are as effective as larger particles for this reaction.
Area of Science:
- Heterogeneous catalysis
- Surface science
- Computational chemistry
Background:
- Supported platinum catalysts are crucial for NO oxidation.
- Catalytic activity often decreases with decreasing metal particle size due to oxidation.
- The behavior of single-atom catalysts (SACs) can differ significantly from nanoparticles.
Purpose of the Study:
- To investigate the NO oxidation mechanism on single θ-Al2O3 supported platinum atoms using theoretical modeling.
- To experimentally validate the theoretical predictions of NO oxidation activity on single Pt atoms.
- To compare the activity of single Pt atoms with platinum nanoparticles for NO oxidation.
Main Methods:
- First-principles density functional theoretical (DFT) modeling.
- Experimental evaluation of single θ-Al2O3 supported platinum atoms.
- Measurement and comparison of turnover frequencies (TOF) for single Pt atoms and Pt nanoparticles.
Main Results:
- Theoretical modeling indicates NO oxidation is feasible on single θ-Al2O3 supported Pt atoms via a modified Langmuir-Hinshelwood pathway.
- Experimentally, single θ-Al2O3 supported Pt atoms demonstrated remarkable NO oxidation activity.
- The turnover frequencies (TOF) for single supported Pt atoms were comparable to those of platinum nanoparticles.
Conclusions:
- Single θ-Al2O3 supported Pt atoms exhibit high NO oxidation activity, challenging the trend of decreasing activity with smaller particle sizes.
- The study elucidates that NO oxidation activity on supported Pt decreases with decreasing particle size but accelerates at the single-atom limit.
- This work highlights the unique catalytic properties of single-atom catalysts for NO oxidation reactions.
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