4 single-shelled hollow cubes (HCs) is described. The crystallinity, morphology, and
microstructure of the as-synthesized ZnO@ Co 3 O 4 HCs are characterized in detail by X-
ray diffraction, field-emission scanning electron microscopy, energy dispersive X-ray
spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and
thermo gravimetric analysis. The results confirm that ZnO@ Co 3 O 4 HCs with porous …