Template-free synthesis and high photocatalytic activity of hierarchical Zn2GeO4 microspheres

Hierarchical Zn2GeO4 microspheres have been successfully synthesized via a simple template-free and mild hydrothermal method, using Zn(NO3)(2)center dot 6H(2)O and GeO2 as Zn and Ge sources, respectively. The as-prepared samples were characterized by XRD, SEM, FESEM, TEM, nitrogen adsorption, UV-vis diffuse reflectance spectrum, and FTIR. The hierarchical Zn2GeO4 microspheres were found to be constructed of randomly aggregated nanorods which have dimensions of about 0.5-1 mu m in length and 200-500 nm in width. A formation mechanism of hierarchical Zn2GeO4 microspheres was proposed. The hierarchical Zn2GeO4 microspheres exhibited relatively high photocatalytic activities and stability for degradation of organic pollutants under UV light irradiation. In addition, the radical species involved in the degradation process have been investigated by using the PL spectra and scavenger experiments.