Patched bimetallic surfaces are active catalysts for ammonia decomposition
Wei Guo1,2,3, Dionisios G Vlachos1
1Department of Chemical and Biomolecular Engineering, Catalysis Center for Energy Innovation, University of Delaware, Newark, Delaware 19716, USA.
Nature Communications
|October 8, 2015
Summary
Core-shell nanoparticles boost ammonia decomposition by creating dual active sites. Nickel terraces break N-H bonds, while edge sites link nitrogen atoms, enhancing catalytic activity.
Area of Science:
- Heterogeneous catalysis
- Materials science
- Surface chemistry
Background:
- Ammonia decomposition is a model reaction for catalyst development.
- Bimetallic nanoparticles show high activity, but active sites are poorly understood.
- Experimental characterization of active sites in nanoparticles is challenging.
Purpose of the Study:
- To elucidate the role of nickel-Pt(111) core-shell structures in ammonia decomposition.
- To identify and characterize the dual active sites responsible for high catalytic activity.
- To understand structure sensitivity and reaction condition effects on catalysis.
Main Methods:
- Multiscale simulations were employed.
- Ammonia decomposition was studied on various nickel loadings on platinum (111).
- Active site characterization and reaction mechanisms were investigated.
Main Results:
- Core-shell structures require guest metal (nickel) patches for dual active sites.
- Nickel terraces facilitate N-H bond breaking.
- Nickel edge sites promote atomic nitrogen association.
- Structure sensitivity is highly dependent on reaction conditions.
- Significant differences observed between transient and steady-state active sites.
Conclusions:
- Dual active sites, comprising nickel terraces and edge sites, are crucial for high ammonia decomposition activity.
- Understanding these sites provides insights into optimal catalyst design for ammonia decomposition.
- Reaction conditions profoundly influence catalyst performance due to competing elementary steps.
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