Supported Core@Shell Electrocatalysts for Fuel Cells: Close Encounter with Reality

Abstract

Core@shell electrocatalysts for fuel cells have the advantages of a high utilization of Pt and the modification of its electronic structures toward enhancement of the activities. In this study, we suggest both a theoretical background for the design of highly active and stable core@shell/C and a novel facile synthetic strategy for their preparation. Using density functional theory calculations guided by the oxygen adsorption energy and vacancy formation energy, Pd3Cu1@Pt/C was selected as the most suitable candidate for the oxygen reduction reaction in terms of its activity and stability. These predictions were experimentally verified by the surfactant-free synthesis of Pd3Cu1/C cores and the selective Pt shell formation using a Hantzsch ester as a reducing agent. In a similar fashion, Pd@Pd4Ir6/C catalyst was also designed and synthesized for the hydrogen oxidation reaction. The developed catalysts exhibited high activity, high selectivity, and 4,000 h of long-term durability at the single-cell level.

Gold-promoted structurally ordered intermetallic palladium cobalt nanoparticles for the oxygen reduction reaction

“…9). Even though the HOR activity trend is not reliable when based on the data obtained using a rotating disc electrode due to the fast kinetics of HOR on Pt and Pd electrodes 44,45 , we are using these results to show that intermetallic structures of AuPdCo catalyst can be used in much broader applications in heterogeneous catalysis.…”

Pt-Based Core–Shell Catalyst Architectures for Oxygen Fuel Cell Electrodes

“…The different areas inside the ellipsoidal particle showing distinct intensity contrast features (Figure 6c) were denoted with numbers in the schematic representation ( Figure 6d). As shown in Figure 6e, the corresponding EELS line scan across the particle shows a high Co concentration at the center (1) and two additional pronounced off-center Co peaks at ~1.8 and ~5 nm (3). In particular, in the thin bright area (2), the Co signal showed minima, indicating a local depletion of the Co concentration several atomic layers below the particle surface.…”

“…[1][2][3] Over past years, the anode loading for the hydrogen oxidation reaction (HOR, 4 the catalytic activity of precious ORR electrocatalysts is to increase at least 4 -5 fold compared to that for state-of-the-art Pt nanocatalyst. [9][10][11][12] Improvements in activity and durability for electrocatalysts are only achieved by better understanding of the ORR kinetics and its mechanisms as well as catalyst degradation mechanisms under operating fuel cell conditions.…”

Morphological and compositional characteristics of bimetallic core@shell nanoparticles revealed by MEIS

“…Nowadays, bimetallic NPs still are of immense interest from both, the scientific and the technological points of view, since their physical properties can be controlled by tuning the NP characteristics such as size, shape, composition, crystallinity and surface properties. Bimetallic core@shell NPs form an important class of nanostructures whose applications are linked to catalysis, cancer immunotherapy, hydrogen fuel-cell devices and plasmonics among others [2][3][4][5][6][7][8][9][10]. In these systems, each NP has a multicomponent nature and its parameters can be individually tuned to manipulate the desired properties accordingly with a specific application.…”