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

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.