Tailoring Au-core Pd-shell Pt-cluster nanoparticles for enhanced electrocatalytic activity

Abstract

We have rationally synthesized and optimized catalytic nanoparticles consisting of a gold core, covered by a palladium shell, onto which platinum clusters are deposited (Au@Pd@Pt NPs). The amount of Pt and Pd used is extremely small, yet they show unusually high activity for electrooxidation of formic acid. The optimized structure has only 2 atomic layers of Pd and a half-monolayer equivalent of Pt (theta(Pt) approximate to 0.5) but a further increase in the loading of Pd or Pt will actually reduce catalytic activity, inferring that a synergistic effect exists between the three different nanostructure components (sphere, shell and islands). A combined electrochemical, surface-enhanced Raman scattering (SERS) and density functional theory (DFT) study of formic acid and CO oxidation reveals that our core-shell-cluster trimetallic nanostructure has some unique electronic and morphological properties, and that it could be the first in a new family of nanocatalysts possessing unusually high chemical reactivity. Our results are immediately applicable to the design of catalysts for direct formic acid fuel cells (DFAFCs).NSFC[20620130427]; MOST[2007DFC40440]; 973 Program[2009CB930703, 2007CB815303]; ENS; CNRS (UMR, LIA XiamENS)[8640

Recent Development of Pd-Based Electrocatalysts for Proton Exchange Membrane Fuel Cells

“…On Pt catalyst, formic acid oxidation also took place via the third pathway with bridge bonded adsorbed formate intermediate being in equilibrium with the solution formats [36][37][38].…”

“…The core-shell structure is effective to reduce cost by reducing the amount of Pd used in the catalyst. Fang et al [37] prepared the Au@Pd@Pt structure with a gold core, a Pd shell and Pt clusters on the shell as shown in Figure 4. The optimized structure had only two atomic layers of Pd and a half-monolayer equivalent of Pt.…”

Au@Pt dendrimer encapsulated nanoparticles as model electrocatalysts for comparison of experiment and theory

“…[12][13][14][15][16] This phenomenon has been applied to electrocatalytic 14,15,17 and spectroscopic applications. 16 Early examples demonstrating the importance of Pt-shell nanoparticles as active electrocatalysts for the ORR were reported by Adzic and coworkers.…”

“…14,15,18 The relationship between bimetallic nanoparticle structure and catalytic activity has been correlated to DFT calculations by a number of groups. 17,[19][20][21] Notably, Nørskov and coworkers have demonstrated trends in oxygen reduction electrocatalyst activity based on the binding energy of oxygen and other reaction intermediates to the metal surface.…”

Rapid Green Synthetic Protocol for Novel Trimetallic Nanoparticles

“…However, there have been only few reports of trimetallic nanoparticles in the literature. The reported trimetallic nanoparticles were synthesized by only thermal heating method [10][11][12][13][14].…”