Cathodic Corrosion of a Bulk Wire to Nonaggregated Functional Nanocrystals and Nanoalloys

Abstract

A key enabling step in leveraging the properties of nanoparticles (NPs) is to explore new, simple, controllable, and scalable nanotechnologies for their syntheses. Among “wet” methods, cathodic corrosion has been used to synthesize catalytic aggregates with some control over their size and preferential faceting. Here, we report on a modification of the cathodic corrosion method for producing a range of nonaggregated nanocrystals (Pt, Pd, Au, Ag, Cu, Rh, Ir, and Ni) and nanoalloys (Pt50Au50, Pd50Au50, and AgxAu100–x) with potential for scaling up the production rate. The method employs poly(vinylpyrrolidone) (PVP) as a stabilizer in an electrolyte solution containing nonreducible cations (Na+, Ca2+), and cathodic corrosion of the corresponding wires takes place in the electrolyte under ultrasonication. The ultrasonication not only promotes particle–PVP interactions (enhancing NP dispersion and diluting locally high NP concentration) but also increases the production rate by a factor of ca. 5. Further increase in the production rate can be achieved through parallelization of electrodes to construct comb electrodes. With respect to applications, carbon-supported Pt NPs prepared by the new method exhibit catalytic activity and durability for methanol oxidation comparable or better than the commercial benchmark catalyst. A variety of AgxAu100–x nanoalloys are characterized by ultraviolet–visible absorption spectroscopy and high-resolution transmission electron microscopy. The protocol for NP synthesis by cathodic corrosion should be a step toward its further use in academic research as well as in its practical upscaling.

Nanoscale morphological evolution of monocrystalline Pt surfaces during cathodic corrosion

“…However, the atomistic aspects of the structural transformation and the surface evolution during cathodic corrosion are still poorly understood. So far, experiments using polycrystalline wires ( 10 – 17 ) have shown that the corrosion is anisotropic, and the surface roughening generated by cathodic corrosion is more pronounced around grain boundaries ( 14 ). The extent of roughness may, therefore, vary depending on the crystallographic distribution ( 11 – 13 ), electrolyte properties ( 14 , 15 ), and the pretreatment of the electrode ( 13 ).…”

Thermally regenerative copper nanoslurry flow batteries for heat-to-power conversion with low-grade thermal energy

“…The production of the Cu particles for the slurry electrode is carried out via the cathodic corrosion method, which is inspired from Koper et al 39,40 An automatized set-up for Cu corrosion is developed for a constant production. The motorized equipment drives a thin Cu wire (dia.…”

New Electrochemical Approach for the Synthesis of Pd‐PdO/C Electrocatalyst and Application to Formic Acid Electrooxidation

“…The such developed catalysts exhibit not only good activity in various catalytic and electrocatalytic processes, but also the ability to form platinum upon the application of the alternating pulse current to the Pt foil electrodes . Moreover, the information on the electrochemical methods of synthesis of Pd‐based catalysts, using electrochemical reduction of Pd ions from its salt solutions or decomposition of a Pd electrode in Pd nanoparticles at a high cathodic potential is scarce.…”