Self-assembling and complex, nanoscale mesocrystals can be tuned for a
variety of uses

Date:
February 8, 2022
Source:
KTH, Royal Institute of Technology
Summary:
A research team has found the key to controlled fabrication of
cerium oxide mesocrystals, according to a recent report. The
research is a step forward in tuning nanomaterials that can serve
a wide range of uses -- including solar cells, fuel catalysts and
even medicine.



FULL STORY ==========================================================================
A research team from KTH Royal Institute of Technology and Max Planck
Institute of Colloids and Interfaces reports to have found the key to controlled fabrication of cerium oxide mesocrystals. The research is
a step forward in tuning nanomaterials that can serve a wide range of
uses -- including solar cells, fuel catalysts and even medicine.


========================================================================== Mesocrystals are nanoparticles with identical size, shape and
crystallographic orientation, and they can be used as building
blocks to create artificial nanostructures with customized optical,
magnetic or electronic properties. In nature, these three-dimensional structures are found in coral, sea urchins and calcite desert rose,
for example. Artificially-produced cerium oxide (CeO2) mesocrystals --
or nanoceria -- are well-known as catalysts, with antioxidant properties
that could be useful in pharmaceutical development.

"To be able to fabricate CeO2 mesocrystals in a controlled way, one
needs to understand the formation mechanism of these materials," says
Inna Soroka, a researcher in applied physical chemistry at KTH. She says
the team used radiation chemistry to reveal for the first time the ceria mesocrystal formation mechanism.

Because of their complexity, mesocrystal formation doesn't follow the
same path as ordinary crystals -- a process called Ostwald Ripening, where smaller particles in solution dissolve and deposit on larger particles.

The researchers found that a gel-like, amorphous phase forms a matrix
in which primary particles, about 3nm in size, align with each other, self-assembling into mesocrystals with a diameter of 30nm.

"If the mesocrystal was a house, this amorphous phase plays the role of
the cement that connects the aligned bricks in the walls, Dr. Soroka says.

They also found that the mesocrystals can further self-organize and form supracrystals, visible to the naked eye. "Just as an architect may design
not a single house but a whole neighborhood with the houses oriented in
a certain way to serve the needs of their inhabitants," she says.

This multi-level hierarchical architecture of supracrystals
is an interesting concept for future materials design, she
says. "People are fascinated by the variety of structures and
complex forms that are found in nature, such as sea urchins and
corals. And scientists are interested in how the crystallation
processes work. Our work is a contribution to this understanding." ========================================================================== Story Source: Materials provided by
KTH,_Royal_Institute_of_Technology. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Zhuofeng Li, Diana Piankova, Yi Yang, Yuta Kumagai, Hannes
Zschiesche,
Mats Jonsson, Nadezda V. Tarakina, Inna L. Soroka. Radiation
Chemistry Provides Nanoscopic Insights into the Role of Intermediate
Phases in CeO 2 Mesocrystal Formation. Angewandte Chemie
International Edition, 2021; 61 (6) DOI: 10.1002/anie.202112204 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220208104647.htm
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