Ultrasmall Cu2O nanocrystals: facile synthesis, controllable assembly and photocatalytic properties

Abstract

In this work, we have successfully synthesized ultrasmall Cu₂O nanocrystals with uniform sizes through a solution-based method. By virtue of the ideal Cu₂O building blocks, 2D or 3D Cu₂O superstructures can be easily achieved by tailoring the assembly process. The results indicate that diethyl carbonate (DEC) plays a crucial role for controlled self-assembly of Cu₂O nanoparticles into a range of superstructures. Interestingly, the aggregative growths of Cu₂O nanocrystals in the self-assembly process are accompanied by oriented attachment and Ostwald ripening. Furthermore, Cu₂O and Cu₂O–Au 3D colloidal spheres can be also obtained by an emulsion-based bottom-up self-assembly strategy. The results show that, compared with pure Cu₂O nanospheres, the as-obtained Cu₂O–Au nanospheres exhibit remarkable photocatalytic activities in the photodegradation of methyl orange (MO).