Preparation of Flaky Hexagonal Nanoporous Au-Cu and Au Particles via Dealloying

摘要

Nanoporous metals have attracted signifi cant attention owing to their excellent physical,chemical,and biological properties.However,preparing ultrafi ne nanoporous metal particles(1–5μm)with specifi c geometries remains challenging.Herein,we report a simple strategy to prepare ultrafi ne fl aky hexagonal nanoporous Au-Cu and Au particles via dealloying.Mg-based alloy ribbons with ultrafi ne fl aky hexagonal Mg-Au(Cu)-Gd particles dispersed in a Mg-Cu(Au)-Gd metallic glassy matrix were prepared.The size and morphology of the precipitated fl aky hexagonal Mg-Au(Cu)-Gd particles were controlled by the solidifi cation process of a Mg 61 Cu 21 Au 7 Gd 11 alloy melt.Ultrafi ne fl aky hexagonal nanoporous Au-Cu particles(diagonal diameter 2.58±0.44μm,ligament size~28 nm),Au-1 particles(diagonal diameter 2.38±0.35μm,ligament size~83 nm)and Au-2 particles(diagonal diameter 2.39±0.44μm,ligament size~66 nm)were prepared via ultrasonic-assisted dealloying of Mg 61 Cu 21 Au 7 Gd 11 alloy ribbons in 0.25 M HCl/ethanol,1 M HCl/ethanol and 0.25 M HNO 3/ethanol solutions,respectively.The ultrafi ne fl aky hexagonal nanoporous Au-Cu and Au particles with a large specifi c surface area have a uniform particle size and shape,implying that they possess adequate powder fl uidity and excellent catalytic properties.Moreover,the formation mechanism of the MgAu(Cu)Gd phase in solidifi ed Mg-Cu-Au-Gd alloys was discussed.This study provides a novel approach for synthesizing nanoporous metal particles with a specifi c geometry.