Atom-by-Atom Resolution of Structure-Function Relations over Low-Nuclearity Metal Catalysts

Area of Science:

• Heterogeneous catalysis
• Surface science
• Materials chemistry

Background:

• Controlling structure sensitivity in metal catalysis is key for atom-efficient processes.
• At the nanoscale, individual atoms significantly impact catalytic properties, presenting synthetic and analytical challenges.
• Current understanding often relies on surface science model systems.

Purpose of the Study:

• To investigate the interplay between geometry, electronic structure, and reactivity of palladium ensembles (atoms, dimers, trimers).
• To exploit the coordination chemistry of carbon nitride for precise catalyst design.
• To understand application-dependent requirements for active catalytic sites.

Main Methods:

• Utilizing carbon nitride's coordination chemistry to create well-defined palladium ensembles.
• Employing a combination of experimental catalytic tests and computational simulations.
• Analyzing palladium atoms, dimers, and trimers to study their properties.

Main Results:

• Demonstrated that palladium nuclearity (number of atoms) critically affects catalytic performance.
• Observed that in alkyne semi-hydrogenation, nuclearity mainly impacts activity.
• Found that in Suzuki coupling, selectivity and stability are more sensitive to nuclearity.

Conclusions:

• The number of atoms in a catalytic ensemble is a crucial design parameter.
• Different catalytic reactions have distinct requirements for the active site's atomic composition.
• This approach offers practical insights for designing heterogeneous catalysts with controlled atomic ensembles.