Abstract:
A combination of long-term aging studies and molecular dynamics (MD) simulations
has been successfully used to explain the time-dependent hierarchical assembly
of ceria nanoparticles (CNPs). When the CNPs were aged in as-synthesized
condition at room temperature in water, it was observed that the individual 3−5
nm CNPs result in octahedral superstructures through a fractal assembly. This
hierarchical fractal self-assembly was observed despite the absence of any
surfactant, at room temperature, and under atmospheric pressure. High resolution
transmission electron microscopy (HRTEM) and fast Fourier transform (FFT)
analysis have been used to explore the assembly of the individual nanoparticles
into fractal superoctahedra. Both experimental work and theoretical analysis
showed that the initial octahedral and truncated octahedral seeds symmetrically
assemble and result in the superoctahedra with intermediate transformation step
