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Hydrogen activation and metal hydride formation trigger cluster formation from supported iridium complexes
Jing Lu1, Ceren Aydin, Nigel D Browning
1Department of Chemical Engineering and Materials Science, University of California, One Shields Avenue, Davis, California 95616, United States.
Journal of the American Chemical Society
|March 9, 2012
Summary
Researchers studied iridium cluster formation from supported iridium complexes using H(2). Key steps involve iridium hydride formation and bond breaking, controllable via ligand choice.
Area of Science:
- Heterogeneous catalysis
- Materials science
- Nanoparticle formation
Background:
- Supported metal complexes are crucial catalysts.
- Understanding cluster formation is key to catalyst design.
- Iridium complexes offer unique catalytic properties.
Purpose of the Study:
- To investigate the initial stages of iridium cluster formation.
- To elucidate the mechanism of cluster nucleation from supported mononuclear complexes.
- To explore the influence of ligands and support interactions on cluster growth.
Main Methods:
- Spectroscopy techniques were employed to monitor the reaction.
- Atomic-resolution scanning transmission electron microscopy (STEM) provided detailed structural insights.
- Controlled experiments under hydrogen (H(2)) atmosphere at specific temperature and pressure were conducted.
Main Results:
- The formation of iridium hydride was identified as a key intermediate.
- Activation of H(2) and breaking of iridium-support bonds initiate cluster formation.
- Ligand choice, including the support itself, was found to control reactivity.
Conclusions:
- The study reveals a detailed mechanism for iridium cluster nucleation.
- Catalyst ligand design is a critical factor in controlling nanoparticle formation.
- These findings contribute to the rational design of supported iridium catalysts.
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