Hierarchical structured ZnFe2O4@RGO@TiO2 composite as powerful visible light catalyst for degradation of fulvic acid

Hierarchical structured ZnFe2O4@ reduced graphite oxide@TiO2 (ZnFe2O4@RGO@TiO2) nanocomposite was prepared by an electrostatic layer-by-layer route, which played a synthetic effect of Fenton oxidation of ZnFe2O4 and photocatalytic oxidation of TiO2 to degrade fulvic acid (FA) solution under visible-light irradiation. In this method, RGO, as the middle layer, can effectively promote the photo-induced electron flow between the ZnFe2O4 and TiO2 and further improve the efficiency of the photo-Fenton oxidation. The influencing factors on photo-Fenton oxidation, including solution pH, catalyst, and H2O2 dosage, have also been investigated. The results illustrated that the ternary composite presented the enhanced catalytic performance. Under visible light irradiation, the degradation efficiency of the sample on the FA solution can reach 95.4% within 3 h. In addition, the catalyst exhibited superior stability and reusability, and its degradation efficiency was still up to 90% after 5 cycles. Therefore, the composite will be a kind of efficient photocatalyst and had a promising application for visible-light driven destruction of organic pollutants.