Ultra-rapid synthesis of the MgCu2 and Mg2Cu Laves phases and their facile conversion to nanostructured copper with controllable porosity; an energy-efficient, reversible process

Abstract

Phase-pure MgCu₂ and high-purity Mg₂Cu have been synthesised within 1 min from elemental powders via the microwave-induced metal plasma (MIMP) approach for the first time. Subsequent room temperature, acidic de-alloying led to 3-dimensional nanoporous (NP) Cu within minutes. Each distinctive metallic matrix exhibited a large surface area with a porosity of either 37.47% (from MgCu₂) or 56.25% (from Mg₂Cu). Both NP Cu powders are composed of crystalline grains (“ligaments”) measuring tens of nanometers across, which exhibit rich point- and extended defects. The selection of Laves precursor dictates the form of ligament obtained, which directs the ensuing NP structure. Working electrodes of both types of NP Cu presented reliable linear non-enzymatic sensing properties over glucose concentrations of 0.5–4.5 and 4.5–10.0 mM with high confidence levels (>99%). This study provides a facile, rapid and energy-efficient route to functional NP Cu with eclectic structures, which should be equally applicable to other metals.