Journal home page for Nano Today
https://doi.org/10.1016/j.nantod.2023.101916Get rights and content material

Highlights

  • Ageing mechanisms are recognized and are depending on temperature.

  • Collective floor diffusion occasions drive growing old of nanoparticles.

  • Metastable shapes transition to thermodynamically secure nanoobjects.

  • A “curved” Arrhenius plot is proposed to account for various growing old mechanisms.

  • It may be of nice curiosity for nanozymatic functions and biomimetic units.

Summary

Thermal growing old can modify the distinctive properties of a nanomaterial by way of structural change. Mechanistic understanding of the growing old course of, together with accelerated growing old below high-temperature working situations, is a primary step in the direction of property preservation by way of controlling, limiting, or suppressing aging-related processes. Right here, we use molecular dynamics to simulate thermal growing old of ceria nanocubes and nanorods, which rework into nanopolyhedra; comparisons with experimental TEM photos are introduced alongside. We discover that morphology modifications proceed by way of the turbulent mobility of CexOy floor clusters from one a part of the nanoceria to a different. For nanorods and nanocubes, catalytically necessary {100} and {110} surfaces are eroded, whereas the relative space of {111} surfaces improve. Detailed evaluation of the simulations reveals that atoms within the CexOy clusters don’t all transfer concurrently. Slightly, (-O-Ce-O-Ce-O-)n ‘chains’ (subsets of the bigger CexOy clusters) transfer with collective movement, whereas the atoms contained in the chains transfer in a ‘worm-like’ trend. This reduces the activation vitality barrier related to all of the atoms within the chain concurrently shifting into an activated (saddle level) configuration. We predict gadolinium-doped ceria nanocubes, charge-compensated by oxygen vacancies, age sooner than undoped and totally oxidised ceria nanocubes. Specifically, dopants that improve catalytic exercise, can also speed up growing old by introducing oxygen vacancies that break the (-O-Ce-O-Ce-O-)n chains into smaller chains with decreased activation energies. Accordingly, we advocate that when doping is used to confer catalytic exercise, experiment must also goal the collective movement of floor (-O-Ce-O-Ce-O-)n chains to maximise thermal stability.

Key phrases

Cerium oxide

Ageing nanorods

Ageing nanocubes

Ageing nanomaterials

Thermal growing old

Molecular modelling

Collective movement

Information Availability

Uncooked computational information associated to this text will be discovered at https://doi.org/10.17632/jdnkf84zj4.1

© 2023 The Creator(s). Revealed by Elsevier Ltd.