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

Abstract

A matter of size: The particle size effect on the activity of the oxygen reduction reaction of size‐selected platinum clusters was studied. The ORR activity decreased with decreasing Pt nanoparticle size, corresponding to a decrease in the fraction of terraces on the surfaces of the Pt nanoparticles (jk=kinetic current density, see picture).

Key Factors Affecting the Performance and Durability of Cathode Electrocatalysts in Polymer Electrolyte Fuel Cells Characterized by In Situ Real Time and Spatially Resolved XAFS Techniques

“…Figure 3 (bottom A) shows the variation of the Pt L IIIedge XANES white line peak heights at 0.4 V with the specific power density [51], which is in agreement with the linear relationship between ORR activity and d-band center shift for Pt 3 Co, Pt 3 Ni, and Pt [70][71][72]. Although we did not investigate the particle size effect on the structural kinetics, the ORR kinetics may not be affected by the particle size of Pt cathode electrocatalysts (below 5 nm size) [73,74]. The enhancements of the rate constants by the Co and Ni addition to Pt/C are shown in Fig.…”

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“…Most, albeit not all, theoretical and experimental studies seem to suggest that the surface specific activity for oxygen reduction should decrease with a decrease in particle size. 12,[22][23][24][25][26][27][28] However, this notion is in conflict with the experimental observation that extended single crystal stepped Pt surfaces sometimes exhibit higher oxygen reduction activity than unstepped surfaces. [29][30][31] One strategy to improve the activity of Pt is to alloy it with other metals.…”

Probing the surface oxidation of chemically synthesised gold nanospheres and nanorods

“…Central to this is the use of capping agents to ensure that nanoparticles do not agglomerate in solution. The effect of size and shape on electrocatalytic performance of metal nanoparticles has been well documented [9][10][11][12]. However, there are other factors that need to be considered when assessing the applicability of an electrocatalyst and that is the presence of defect sites and capping agents.…”