Silver-loaded ZnO/ZnFe2O4 mesoporous hollow spheres with enhanced photocatalytic activity for 2,4-dichlorophenol degradation under visible light irradiation

Silver-loaded ZnO/ZnFe2O4 (ZnO/ZnFe2O4/Ag) mesoporous hollow spheres were synthesized via a layer-bylayer technique followed chemical reduction method. The structures and morphologies of the as-prepared catalysts were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and N-2 adsorption/desorption porosimetry. The photodegradation activities of ZnO/ZnFe2O4/Ag mesoporous hollow spheres toward 2,4-dichlorophenol were investigated under UV and visible light irradiation. The experimental results indicated that our mesoporous hollow spheres exhibited much higher photodegradation activities than P25 for the loading of silver particles, the bands matching and the unique structures. There exists an optimal loading dosage of silver particles. Too high or too low loading will reduce the photodegradation activities of ZnO/ZnFe2O4/Ag mesoporous hollow spheres. The possible mechanism behind was proposed. Noteworthily, the ZnO/ZnFe2O4/Ag mesoporous hollow spheres are reusable with the aid of a magnet, which is cost effective.