Resolving multifrequential oscillations and nanoscale interfacet communication in single-particle catalysis.

Area of Science:

• Heterogeneous catalysis
• Surface science
• Nanomaterials characterization

Background:

• Understanding nanofacet reactivity is crucial for heterogeneous catalysis.
• Previous methods lacked spatial and temporal resolution to study individual facets.
• Rhodium is a key catalyst for reactions like hydrogen oxidation.

Purpose of the Study:

• To resolve the reactivity of individual nanofacets on a single catalyst particle.
• To investigate the coupling and interaction between different nanofacets during catalysis.
• To provide high-resolution insights into oscillatory catalytic reactions.

Main Methods:

• In situ field electron microscopy and field ion microscopy on a curved rhodium crystal.
• High spatial (~2 nm) and temporal (~2 ms) resolution imaging.
• Utilized ionized water as the imaging species to visualize adsorbed species and active sites.
• Microkinetic modeling to support experimental observations.

Main Results:

• Direct imaging of adsorbed species and reaction fronts on individual nanofacets.
• Observed limited interfacet coupling, entrainment, and frequency locking.
• Demonstrated reconstruction-induced collapse of spatial coupling between facets.
• Experimental findings were consistent with microkinetic modeling of oxygen species coverages and oscillation frequencies.

Conclusions:

• Individual nanofacets exhibit distinct catalytic behaviors and limited coupling.
• Facet coupling dynamics are influenced by surface reconstruction and reaction conditions.
• This high-resolution approach advances the understanding of structure-reactivity relationships in heterogeneous catalysis.