Formation of nanoporous Cu-Ag by dealloying Mg-Cu-Y-Ag amorphous alloys and its electrocatalyst oxidation property

• Published in: Intermetallics Vol. 110; p. 106488
• Main Authors: Hyun, J.I., Kong, K.H., Kim, W.C., Kim, W.T., Kim, D.H.
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01-07-2019; Elsevier BV
• Subjects: Amorphous alloy; Amorphous alloys; Aqueous solutions; Bimetallic Cu-Ag; Bimetals; Copper; Dealloying; Electrocatalyst; Electrochemical oxidation; Electrodes; Grain structure; Metallic glasses; Nanoporous structure; Oxidation; Scale (corrosion); Silver; Sodium hydroxide; Solid solubility; Solid solutions; Submerging; Sulfuric acid; Electrocatalyst; Amorphous alloy; Nanoporous structure; Dealloying; Bimetallic Cu-Ag
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/j.intermet.2019.106488

The supersaturated Cu-Ag bimetallic nanoporous structure has been fabricated by dealloying of Mg65Cu25-xY10Agx (x = 0, 2, 4, 8) amorphous alloys and its electrocatalytic property for sodium borohydride (NaBH4) oxidation has been evaluated. In order to increase solid solubility of Ag into Cu, the dealloying process is proceeded in higher concentration sulfuric acid aqueous solution for shorter immersion time. When Mg65Cu25-xY10Agx amorphous alloys are dealloyed in 1.0 M solution for 30 s, the Cu-Ag bimetallic nanoporous structure in the form of solid solution is successfully obtained due to extended solid solubility in nm scale grain structure. Electrochemical oxidation of NaBH4 at Cu-(Ag) electrodes is studied in a mixture solution of 2.0 M NaOH and 0.1 M NaBH4. The electrocatalytic property of nanoporous Cu-Ag bimetallic electrodes is higher than that of Cu monometallic electrode. The electrode dealloyed from Mg65Cu21Y10Ag4 amorphous alloy exhibits the highest electrocatalytic property.
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•Mg-Cu-Y amorphous alloys without and with minor Ag addition are dealloyed.•Dealloying of Mg-Cu-Y-(Ag) results in nanoporous Cu-(Ag).•Solid solution type bimetallic ligament forms with extended solid solubility.•Solutionizing of Ag into Cu improves electrocatalytic property.