Facile synthesis and enhanced visible-light photocatalytic activity of micro/nanostructured Ag2ZnGeO4 hollow spheres

Micro/nanostructured Ag2ZnGeO4 hollow spheres were successfully synthesized by a one-step and low-temperature route under ambient pressure. The micro/nanostructured Ag2ZnGeO4 hollow spheres have a diameter of 1–2 μm and their shells are composed of numerous nanoparticles and nanorods. The growth process of the micro/nanostructured Ag2ZnGeO4 hollow spheres was investigated in detail. The results indicated that the morphologies and composition of Ag2ZnGeO4 samples were strongly dependent on the dose of the AgNO3 and reaction time. Excessive AgNO3 was favorable for the nucleation and growth rate of Ag2ZnGeO4 crystals and the formation of pure Ag2ZnGeO4. Moreover, the formation mechanism of the micro/nanostructured Ag2ZnGeO4 hollow spheres is related to the Ostwald ripening. Under the same conditions, the photocatalytic activity of micro/nanostructured Ag2ZnGeO4 hollow spheres is about 1.7 times and 11 times higher than that of bulk Ag2ZnGeO4 and Degussa P25, respectively. These interesting findings could provide new insight on the synthesis of micro/nanostructured ternary-metal oxides with enhanced photocatalytic activity.