Controlling the {111}/{110} Surface Ratio of Cuboidal Ceria Nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Controlling nanoparticle size and morphology is critical for optimizing catalytic activity.
• Nanoceria (cerium oxide nanoparticles) exhibit tunable properties based on their surface structure.

Purpose of the Study:

• To synthesize cuboidal cerium oxide nanoparticles using microwave-assisted hydrothermal methods.
• To investigate the relationship between synthesis conditions, particle morphology, and surface structure.
• To understand the atomistic origins of nanoceria surface stability and reactivity.

Main Methods:

• Microwave-assisted hydrothermal synthesis in highly alkaline media.
• High-resolution transmission electron microscopy (HRTEM) for structural analysis.
• Molecular dynamics (MD) simulations to rationalize experimental observations.

Main Results:

• Cuboidal cerium oxide nanoparticles were successfully synthesized, with edges truncated by CeO₂{110} and corners by CeO₂{111} surfaces.
• Increasing NaOH concentration increased particle size, while {110} and {111} facets remained constant.
• MD simulations confirmed energetic stabilization of nanocubes by {111} and {110} surface truncation, with a minimum size of ~1.6 nm.
• {100} surfaces exhibited "liquid-like" behavior with high oxygen mobility, contrasting with stable {111} surfaces.

Conclusions:

• The study elucidates the role of specific crystallographic facets in stabilizing nanoceria morphology.
• Surface energy and oxygen mobility vary significantly across different nanoceria facets ({100}, {110}, {111}).
• Findings provide insights for designing advanced, catalytically active nanoceria materials.