Kinetically Controlled Autocatalytic Chemical Process for Bulk Production of Bimetallic Core–Shell Structured Nanoparticles

Abstract

Although bimetallic core@shell structured nanoparticles (NPs) are achieving prominence due to their multifunctionalities and exceptional catalytic, magnetic, thermal, and optical properties, the rationale underlying their design remains unclear. Here we report a kinetically controlled autocatalytic chemical process, adaptable for use as a general protocol for the fabrication of bimetallic core@shell structured NPs, in which a sacrificial Cu ultrathin layer is autocatalytically deposited on a dimensionally stable noble-metal core under kinetically controlled conditions, which is then displaced to form an active ultrathin metal-layered shell by redox-transmetalation. Unlike thermodynamically controlled under-potential deposition processes, this general strategy allows for the scaling-up of production of high-quality core-shell structured NPs, without the need for any additional reducing agents and/or electrochemical treatments, some examples being Pd@Pt, Pt@Pd, Ir@Pt, and Ir@Pd. Having immediate and obvious commercial potential, Pd@Pt NPs have been systematically characterized by in situ X-ray absorption, electrochemical-FTIR, transmission electron microscopy, and electrochemical techniques, both during synthesis and subsequently during testing in one particularly important catalytic reaction, namely, the oxygen reduction reaction, which is pivotal in fuel cell operation. It was found that the bimetallic Pd@Pt NPs exhibited a significantly enhanced electrocatalytic activity, with respect to this reaction, in comparison with their monometallic counterparts.

Sn@Pt and Rh@Pt core–shell nanoparticles synthesis for glycerol oxidation

“…According with TEM results reported by Taufany et al for Pd@Pt/C core-shell structure [33], it is possible to suggest that the formation of a core-shell structure with a dense concentration of Sn or Rh in the core and a distribution of Pt on the surface was obtained. However, the core and shell components on Rh/Sn@Pt nanoparticles are not easily differentiable due to the fact that Rh, Sn, and Pt exhibit the same imaging contrast.…”

Synthesis and catalytic properties of bimetallic nanomaterials with various architectures

“…In general, bimetallic core-shell nanoparticles are prepared by seed-mediated growth or one-pot co-reduction of metallic precursors [77][78][79][80]. Actually, the one-pot coreduction process is similar to seed-mediated growth in nature.…”

“…The pre-formed metal will serve as in situ seeds for the successive reduction and growth of another metal. So far, bimetallic core-shell nanocrystals with well-defined shapes have been synthesized by many groups [77][78][79][80][81][82]. For example, Zheng and co-workers reported the synthesis of Pd@Ag core-shell nanoplates via epitaxial growth of Ag on uniform hexagonal Pd nanoplates [77].…”

Frontiers of Nanoelectrochemistry and Application of Nanotechnology: A Vision for the Future

“…Taufany et al [10] dealt in a phenomenal work on the kinetically controlled autocatalytic chemical process for bulk production of bimetallic core-shell structured nanoparticles. Although bimetallic core-shell structured nanoparticles (NP) are achieving prominence due to their multifunctionalities and exceptional catalytic, magnetic, thermal, and optical properties, the rationale underlying their design remains unclear, and the vision of this domain is immature.…”

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