The Effect of Size on the Oxygen Electroreduction Activity of Mass‐Selected Platinum Nanoparticles

Abstract

Eine Frage der Größe: Der Einfluss der Partikelgröße auf die Aktivität größenselektierter Platin‐Cluster in der Sauerstoffreduktionsreaktion (ORR) wurde untersucht. Die Aktivität der Pt‐Nanopartikel sank mit kleiner werdender Größe der Nanopartikel, entsprechend einer Abnahme des Anteils an Terrassen auf der Oberfläche der Pt‐Nanopartikel (jk=kinetische Stromdichte, siehe Bild).

Structural parameters of supported fuel cell catalysts: The effect of particle size, inter-particle distance and metal loading on catalytic activity and fuel cell performance

“…As these works [22,34,35] were carried out in H 2 SO 4 , considering that sulphate anions can diffuse from aqueous electrolyte across the active layer, the origin of the size effect could be partially due to their adsorption on Pt nanoparticles.Based on structure-activity correlation described by Markovic et al [33,34], different activity trends would be predicted in different electrolytes. Conversely, the same activity trend found in H 2 SO 4 , that is, a decrease of SA with decreasing Pt particle size,was also observed in non-adsorbing HClO 4 [21,[26][27][28][37][38][39][40][41][42][43][44].The independence of the activity trend of the electrolyte has to be ascribed to other effects than the type of terraces ({100} or {111}), such as Pt electronic state [26,27],the edge sites [38] and the potential of zero total charge [28,40], resulting in a stronger interaction of oxygenated species with smaller Pt particles. Takasu et al [27]attributed the particle size effects on the ORR to stronger interaction of oxygen with smaller Pt particles, due to the dependence of Pt electronic state on particle size.…”

“…Efforts to mitigate the poisoning of Pt have been concentrated on both the addition of cocatalysts, particularly ruthenium and tin, to platinum [5,6] and the use of Pt-free catalysts [7,8].On the other hand,kinetic limitations of the oxygen reduction reaction (ORR) on pure Pt are a serious drawback, reducing PEMFC performance [9].To decrease the cathodic cell voltage losses,extensive studies were addressed to the development of ORR catalysts more active than pure Pt.The alloys of transition corner) atoms, simple geometric considerations indicate that the relative concentration of surface atoms on facets or in edge and corner positions changes dramatically as the crystallite size decreases in the 5-1 nm particle range, influencing CO oxidation potential [20]. Perez-Alonso et al [21] reported that the activity for oxygen reduction decreased with decreasing Pt nanoparticle size, corresponding to a decrease in the fraction of terraces on the surfaces of the Pt nanoparticles. Park et al [22] reported that the availability of contiguous Pt terrace sites progressively decreases with decreasing particle.…”

Catalysis by clusters with precise numbers of atoms

“…Utilizing size-selected clusters in electrochemical reactions is a novel application 38,39,96,97 that presents significant difficulty for in situ investigation due to the experimental conditions. Pt n nanoclusters soft-landed on amorphous carbon supports were treated in a standard electrochemical three-electrode set-up to investigate structural changes that occur under electrochemical conditions 98 .…”

Fast Prediction of Adsorption Properties for Platinum Nanocatalysts with Generalized Coordination Numbers

“…Experimentally, this requires facile synthesis methods that permit the preferential formation of active sites with the highest turnover frequencies. [3] From a theoretical standpoint, simple and robust models are required with sound physical-chemical foundations and predictive power, that is, they must be able to univocally locate new information within existing trends. The most successful example of such models is arguably that of Hammer and Nørskov.…”