One-pot synthesis of hexagonal and triangular nickel–copper alloy nanoplates and their magnetic and catalytic properties

Abstract

A facile one-pot route has been developed for the synthesis of hexagonal and triangular Ni–Cu alloy nanoplates. The synthesis was conducted using nickel(II) acetylacetonate and copper(II) chloride dihydrate as metal precursors, trioctylphosphine as a capping agent, and oleylamine as a solvent and reducing agent. Structural analyses from X-ray diffraction and transmission electron microscopy indicate that the as-synthesized nanoplates have an fcc crystalline structure and their side faces are bound by a mixture of {100} and {111} facets, while their top and bottom faces are bound by {111} facets. The oxidative etching effect of Cu(II) on Ni(0) in the presence of Cl ions plays an important role in the generation of the anisotropic nanoplates. The results of magnetic measurements revealed differences between the hexagonal and triangular nanoplates in their ability to undergo the transition from the ferromagnetic to the superparamagnetic state with increasing temperature. The magnetic properties of the as-synthesized Ni–Cu alloy nanoplates can also be tuned by adjusting the Ni content which correlates closely with reaction temperature. Excellent catalytic properties for the catalytic reduction of methylene blue by NaBH₄ in aqueous solution were observed for the as-synthesized nanoplates.