Fabrication of magnetically separable Ag–ZnFe2O4 hollow nanospheres with efficient photocatalytic activity

Environmental pollution seriously affects the survival of human beings. Semiconductor photocatalysis technology is considered to be one of the most effective ways to solve environmental pollution and energy shortage. The high degradation efficiency of nanometric photocatalysts has attracted extensive attention, but the photocatalysts are difficult to recycle and reuse, which limits their application. ZnFe2O4 hollow nano-photocatalysts loaded with different contents of Ag were successfully prepared by template-assisted calcination and photoreduction, and can be conveniently separated from water in a magnetic environment. The results indicate that Ag–ZnFe2O4 possess a hollow nano-shell structure with a particle size distribution of about 280 nm and a shell thickness of about 24 nm. Ag–ZnFe2O4 shows the strongest photocurrent intensity and photocatalytic performance compared to bulk ZnFe2O4 and nano ZnFe2O4. When the concentration of AgNO3 solution is 0.2 mmol, Ag–ZnFe2O4 has the strongest photodegradation efficiency to degrade RhB under visible light irradiation. After several photodegradation experiments, the photodegradation efficiency is only decreased by 2.8 %, further proving that Ag–ZnFe2O4 possess good application value in wastewater treatment.