A general, one-step and template-free synthesis of sphere-like zinc ferrite nanostructures with enhanced photocatalytic activity for dye degradation

Spinel zinc ferrite nanospheres with diameters of about 212 nm were synthesized in high yield via a general, one-step and template-free solvothermal route. The prepared nanospheres had cubic spinel structure and exhibited good size uniformity and regularity. The absorption edge of ZnFe2O4 nanospheres shifted to a higher energy in the UV-Vis absorption spectrum compared with that of ZnFe2O4 nanopartides. The ZnFe2O4 nanospheres exhibited remarkably high surface photovoltage response in the UV and visible region, suggesting the enhanced separation ability of photogenerated electrons and holes. The dramatically enhanced photocatalytic activity of the ZnFe2O4 nanospheres was evaluated in the decomposition of rhodamine B under Xe lamp irradiation. Hydroxyl radicals on the surface of photoilluminated ZnFe2O4 nanospheres were detected by the photoluminescence technique, which suggested that hydroxyl radicals played an important role in the photocatalytic reaction. This study provided new insight into the design and preparation of functional nanomaterials with sphere structure in high yield, and the as-grown architectures demonstrated an excellent ability to remove organic pollutants in wastewater. (c) 2011 Elsevier Inc. All rights reserved.