Sulfur-doped CoFe2O4 nanopowders for enhanced visible-light photocatalytic activity and magnetic properties

Magnetically recoverable sulfur-doped CoFe2O4 nanopowders were used as photocatalyst for degradation of oxytetracycline (OTC) under visible light in aqueous solution. S doped CoFe2O4 nanopowders synthesized by a simple calcining process were characterized by XRD, TEM, VSM, FT-IR, UV-vis DRS and XPS. The results showed that introducing of S element in CoFe2O4 crystal structure narrowed its band gap and increased visible light absorption. 0.3 S-CoFe2O4 exhibited the highest magnetic property and photocatalytic activity. The maximum photocatalytic conversion ratio of OTC reached 90.4% at pH = 8.5 after 5 h irradiation. During photocatalytic process, seven intermediate products were detected, and based on that a detailed degradation path way of OTC was proposed.