Looping metal-support interaction in heterogeneous catalysts during redox reactions

Area of Science:

• Heterogeneous catalysis
• Materials science
• Surface chemistry

Background:

• Metal-support interfaces are crucial for heterogeneous catalyst performance.
• Understanding dynamic interactions at the atomic level is key to catalyst design.

Purpose of the Study:

• To investigate the metal-support interactions in NiFe-Fe3O4 catalysts during the hydrogen oxidation reaction.
• To elucidate the atomic-scale dynamics governing catalytic activity.

Main Methods:

• Operando transmission electron microscopy (TEM) was employed to observe catalyst behavior under reaction conditions.
• In-situ analysis allowed for the visualization of dynamic interface changes.

Main Results:

• A looping metal-support interaction was identified at the NiFe-Fe3O4 interfaces.
• Lattice oxygens reacted with hydrogen, leading to dynamically migrating interfaces.
• Reduced iron atoms migrated and reacted with oxygen molecules, coupling reactions.
• Hydrogen oxidation and support redox reactions were intrinsically coupled via interface migration.

Conclusions:

• The study provides novel mechanistic insights into metal-support interactions.
• Dynamic interface migration plays a critical role in the catalytic cycle.
• Operando TEM is a powerful tool for studying atomic-scale dynamics in catalysis.