Morphologies and microstructures of nano-sized Cu2O particles using a cetyltrimethylammonium template

Hollow polyhedra and cubes of nanostructured Cu2O particles have been synthesized by reduction of CuSO4 with ascorbate acid in the solution phase. The nanostructures were obtained when the cetyltrimethylammonium (CTAB) concentration ranged from 0 to 0.03 M in the presence of NaOH. Structural characterizations, by means of x-ray photoelectron spectroscopy (XPS) for measuring Cu valence states and by electron microscopy for microstructure and chemical analyses, suggest that most Cu2O nanoparticles are covered with a thin CuO shell arising possibly from reaction of the adsorbed oxygen on the Cu2O particle surface. The blue shift is observed as microstructures of Cu2O nanoparticles changed from cubic to hollow in ultraviolet and visible (UV-visible) absorption spectra. Both the Cu2O hollow and cubic nanostructures show certain quantum-confined effects. A cationic CTAB template mechanism is proposed to interpret the formation of the Cu2O nanoparticles.