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

Abstract

The oxygen reduction reaction (ORR) activity and durability of various Au(x)/Pt100 nanoparticles (where x is the atomic ratio of Au against Pt) are evaluated herein. The samples were fabricated on a highly-oriented pyrolytic graphite substrate at 773 K through sequential arc-plasma depositions of Pt and Au. The electrochemical hydrogen adsorption charges (electrochemical surface area), particularly the characteristic currents caused by the corner and edge sites of the Pt nanoparticles, decrease with increasing Au atomic ratio (x). In contrast, the specific ORR activities of the Au(x)/Pt100 samples were dependent on the atomic ratios of Pt and Au: the Au28/Pt100 sample showed the highest specific activity among all the investigated samples (x = 0-42). As for ORR durability evaluated by applying potential cycles between 0.6 and 1.0 V in oxygen-saturated 0.1 M HClO4, Au28/Pt100 was the most durable sample against the electrochemical potential cycles. The results clearly showed that the Au atoms located at coordinatively-unsaturated sites, e.g. at the corners or edges of the Pt nanoparticles, can improve the ORR durability by suppressing unsaturated-site-induced degradation of the Pt nanoparticles.

A Demonstration of Pt L3-Edge EXAFS Free from Au L3-Edge Using Log–Spiral Bent Crystal Laue Analyzers

“…A practical approach, combining different metals with Pt have widely been adopted to reduce the amount of Pt and improve its activity and durability. Among those, Au is one of the interesting metals due to its superior oxygen-reduction-reaction activity and durability reported in Pt-Au nanostructures, where the Pt (shell)-Au (core) structures and the effect of Au decoration on the edges of Pt surfaces are used as a fuel cell catalyst [1][2][3][4][5]. Hence, it is essential to understand the local structures of both Pt and Au in an atomic scale to elucidate the mechanism of the catalytic reactions in Pt-Au nanostructures.…”

Gold Doping in PtCu3/HSAC Nanoparticles and Their Morphological, Structural, and Compositional Changes during Oxygen Reduction Reaction Electrochemical Cycling

“…By blocking these sites with Au (an inert metal), a reduction in degradation can be achieved, and, hence, a better electrochemical durability. Studies were conducted on the theoretical calculations of Au segregation on low‐coordination sites and on the consequences on the stabilization of Pt nanoparticles . Additionally, there are observations of Au clusters decorating small Pt nanoparticles with an improved durability .…”

“…For the PtCu 3 /HSAC system, after 10 000 cycling processes, the number of smaller nanoparticles diminished, in contrast to the PtCu 3 :Au/HSAC system, for which the number of smaller nanoparticles was not modified that much (Figure S9). The latter observation is explained by a suppression of the Ostwald ripening process thanks to the stabilization of the nanoparticles by Au, a behavior also reported in smaller Pt–Au nanoparticles after degradation …”

Cathodic Arc-plasma Deposition of Platinum Nanoparticles on Fluorine-doped Tin Oxide for Electrocatalytic Nitrate Reduction Reaction

“…Pt nanoparticles were produced by cathodic arc plasma deposition (APD) under high vacuum conditions. The APD is a physical vapor deposition technique and provides pure metal [15][16][17] and metal alloy nanoparticles [18][19][20] without neither surfactants nor surface modifiers, which are usually used for solution-based methods and suppress the (electro)catalytic activity. The APD also provides strong adhesion of the deposited metal nanoparticles to substrates because of the generation of metal ion species with high kinetic energies, 21 which can give ideal Pt/Sn interfaces for electrocatalytic reactions.…”