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When Fluxionality Beats Size Selection: Acceleration of Ostwald Ripening of Sub‐Nano Clusters
Author(s) -
Zandkarimi Borna,
Poths Patricia,
Alexandrova Anastassia N.
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202100107
Subject(s) - ostwald ripening , sintering , metastability , materials science , chemical physics , cluster (spacecraft) , surface energy , dissociation (chemistry) , nanoparticle , nanotechnology , chemical engineering , chemistry , metallurgy , computer science , composite material , organic chemistry , engineering , programming language
Size selection was demonstrated to suppress Ostwald ripening of supported catalytic nanoparticles. When the supported clusters are subnanometer in size and highly fluxional, such as Pt clusters on the rutile TiO 2 (110) surface, this paradigm breaks down, and the established theory of sintering needs a revision. At temperatures characteristic of catalysis (i.e. 700 K), sub‐nano clusters thermally populate many low‐energy metastable isomers. As these isomers all have different geometric and electronic structures, and thus, formation and dissociation energies (in lieu of surface energy), Ostwald ripening is not suppressed, despite the size‐selection. However, some clusters arise as magic numbers in terms of sintering stability at the ensemble level. Acceleration of sintering by metastable species persists though weakens in polydisperse cluster systems. We propose a competing pathways theory for sintering, which at the atomistic level describes the found size‐specific sintering behavior.