Ostwald ripening of charged supported metal nanoparticles: Schottky model

• Sintering of supported metal nanoparticles is discussed.
• The focus is on bimodal particle size distributions.
• This feature may be related to charge of particles.
• The Schottky model does not, however, support this hypothesis.

Due to high surface area, supported metal nanoparticles are thermodynamically prone to sintering. The experimental studies of this process exhibit sometimes transient bimodal particle size distributions. Such observations may result from the support heterogeneity. Looking retrospectively, one can also find the prediction that in the case of Ostwald ripening this feature can be related to charge of metal nanoparticles. In real systems, this charge is often associated with the metal–support interaction and can be interpreted in the framework of the Schottky model. Using this model, the author shows that the charge redistribution cannot be behind bimodal particle size distributions. Moreover, the corresponding contribution to the driving force for Ostwald ripening is typically much smaller than the conventional one.

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