Synthesis and evolution of hollow ZnO microspheres assisted by Zn powder precursor

Hollow ZnO microspheres with nanowires grown on the inner and outer surfaces (HZMSnws) have been successfully synthesized by a simple two-step thermal process approach, where pre-deposited Zn powder particles on Si substrates act as temporary templates to form hollow ZnO sphere shells, while additional Zn powder acts as a Zn source to grow single crystal nanowires on the surfaces of spherical shells. SEM, XRD, TEM and HRTEM were used to characterize the morphology and crystalline structure of the samples. Photoluminescence (PL) measurement shows strong UV emission (380 nm) of HZMSnws samples. Lacking the need for the additional template removal is an important advantage of this approach over others and it therefore can be used to prepare hollow ZnO nano/microsphere shells (HZMSs) and HZMSnws at low cost and at large scale. These kinds of special high surface area hollow spherical structures may find potential applications in photocatalysis, light-weight composite fillers, acoustic insulation, UV nano/micro-optoemission devices and photoanodes of dye-sensitized solar cells.