A surfactant free synthesis and formation mechanism of hollow Cu2O nanocubes using Cl− ions as the morphology regulator

Abstract

Hollow nanomaterials have attracted intense attention due to their special structures and potential applications in many fields. In this paper, we report a surfactant free synthesis of hollow Cu₂O nanocubes by reducing Cu²⁺ precursors using Cl⁻ ions as the morphology regulator at room temperature. It is found that in the presence of Cl⁻ ions, hollow Cu₂O nanocubes can be easily synthesized by directly reducing Cu²⁺ precursors with ascorbic acid. Through well-designed experiments, we propose that, in this surfactant free synthetic route, the formation of hollow Cu₂O nanocubes results from a reaction activated Kirkendall diffusion process of cubic CuCl intermediates, which are formed in the reaction process and act as self-sacrificial templates. The amounts of Cl⁻ ions and NaOH are two key factors to determine whether hollow Cu₂O nanocubes are formed or not.