High Sintering Resistance of Size-Selected Platinum Cluster Catalysts by Suppressed Ostwald Ripening

Abstract

Employing rationally designed model systems with precise atom-by-atom particle size control, we demonstrate by means of combining noninvasive in situ indirect nanoplasmonic sensing and ex situ scanning transmission electron microscopy that monomodal size-selected platinum cluster catalysts on different supports exhibit remarkable intrinsic sintering resistance even under reaction conditions. The observed stability is related to suppression of Ostwald ripening by elimination of its main driving force via size-selection. This study thus constitutes a general blueprint for the rational design of sintering resistant catalyst systems and for efficient experimental strategies to determine sintering mechanisms. Moreover, this is the first systematic experimental investigation of sintering processes in nanoparticle systems with an initially perfectly monomodal size distribution under ambient conditions.

Low-temperature atomic layer deposition delivers more active and stable Pt-based catalysts

“…The tendency of an ensemble of NPs to sinter depends, in fact, not only on the temperature but also on the shape of the initial PSD, the reaction environment, and the presence of carbonaceous species adsorbed on the catalyst surface. 1,2,27,[44][45][46] The initially narrow PSD of the Pt NPs synthesized at low temperature can effectively suppress sintering due to Ostwald ripening, given that the driving force of such mechanism lies in the PSD span. 44 Furthermore, the PSD of the Pt/GNP/10L NPs was not only narrow but also symmetric, whereas the Pt/GNP/10H composite had a large number of small NPs coexisting next to large ones.…”

“…1,2,27,[44][45][46] The initially narrow PSD of the Pt NPs synthesized at low temperature can effectively suppress sintering due to Ostwald ripening, given that the driving force of such mechanism lies in the PSD span. 44 Furthermore, the PSD of the Pt/GNP/10L NPs was not only narrow but also symmetric, whereas the Pt/GNP/10H composite had a large number of small NPs coexisting next to large ones. Sintering simulations using the experimental PSDs of both the Pt/GNP/ 10L and the Pt/GNP/10H composites as the initial condition clearly show that the latter sinters much faster than the former (see Fig.…”

Oxygen reduction reaction activity and structural stability of Pt–Au nanoparticles prepared by arc-plasma deposition

“…it involves the growth of larger particles at the expense of the smaller ones. 4,45 Consequently, the particle-size distribution generally shifts to larger values, showing a tail toward larger particle sizes. The STM images of Pt 100 NPs (Fig.…”

Understanding and Controlling the Aggregative Growth of Platinum Nanoparticles in Atomic Layer Deposition: An Avenue to Size Selection

“…3,6−8 The latter, however, can only be understood and harnessed through the advent of synthesis routes that enable the deposition of NPs with narrow particle size distributions (PSDs), that is, size-selected NPs. 9,10 Despite its potential, the scalable synthesis of size-selected NPs on high-surface-area supports, which are relevant to most practical applications, has so far proved elusive. 10 Atomic layer deposition (ALD) is an established thin-film deposition technique that has recently seen use in the synthesis of supported NPs with very promising results in terms of control over the NP size.…”