Platinum Monolayer on Nonnoble Metal−Noble Metal Core−Shell Nanoparticle Electrocatalysts for O₂ Reduction

Abstract

We synthesized a new class of O2 electrocatalysts with a high activity and very low noble metal content. They consist of Pt monolayers deposited on the surfaces of carbon-supported nonnoble metal-noble metal core-shell nanoparticles. These core-shell nanoparticles were formed by segregating the atoms of the noble metal on to the nanoparticles' surfaces at elevated temperatures. A Pt monolayer was deposited by galvanic displacement of a Cu monolayer deposited at underpotentials. The mass activity of all the three Pt monolayer electrocatalysts investigated, viz., Pt/Au/Ni, Pt/Pd/Co, and Pt/Pt/Co, is more than order of magnitude higher than that of a state-of-the-art commercial Pt/C electrocatalyst. Geometric effects in the Pt monolayer and the effects of PtOH coverage, revealed by electrochemical data, X-ray diffraction, and X-ray absorption spectroscopy data, appear to be the source of the enhanced catalytic activity. Our results demonstrated that high-activity electrocatalysts can be devised that contain only a fractional amount of Pt and a very small amount of another noble metal.

Nanostructured Pt-alloy electrocatalysts for PEM fuel cell oxygen reduction reaction

“…Zhang et al 10,23,96,98 synthesized core-shell structured PtM nanoparticles using galvanic displacement underpotential deposition (UPD), as shown in Fig. 5.…”

“…15 Using preformed nanostructures as seeds, well-defined core-shell structures, nanowires and nanotubes were synthesized. 16,96,98 Mahmoud et al 47 employed tetrahedral Pt as seeds to fabricate star-like Pt nanostructures with up to thirty arms, as shown in Fig. 16.…”

“…7 presents a comparison of ORR activity on such core-shell electrocatalysts. 96 The polarization curves (left side of Fig. 7) were obtained using a rotating disk electrode (RDE) technique.…”

RhCu 3D Nanoframe as a Highly Active Electrocatalyst for Oxygen Evolution Reaction under Alkaline Condition

“…A great improvement in this area has been feasible with facet‐controlled nanoparticles and core–shell nanoparticles with lattice mismatch, which enables surface‐energy modulations 10, 11, 12, 13, 14, 15, 16, 17. Most notably, phenomenal enhancement in catalytic performance has been accomplished by framework nanostructures with dramatically increased surface area per volume, and a great deal of current interest resides on the design and synthesis of novel nanoframework structures 18, 19, 20, 21, 22, 23.…”

First-principles modeling of magnetic misfit interfaces

“…Exciting properties (e.g., optical, electrical, and catalytic) of systems built of magnetic and nonmagnetic materials are well known from nanoparticles. [4][5][6][7] Despite their potential for applications, the physical properties of magnetic/nonmagnetic interfaces, such as the origin of the perpendicular magnetic anisotropy, are not well understood, mainly because they depend on external factors such as the interface quality and the film thickness in thin-film geometries. A change of structural details can strongly alter the electronic states, which in turn influences the magnetic properties.…”