Highly-porous CuFe2O4@ZnFe2O4 yolk-shell heterostructure for photocatalytic reduction of nitrobenzene

Abstract

Developing novel photocatalytic materials and underlying the charge separation mechanisms are keys for achieving excellent performances. However, currently reported photocatalysts suffer low charge separation efficiency and low stability during irradiation. In this work, highly-porous CuFe2O4@ZnFe2O4 yolk-shell heterostructure was prepared by a facile hydrothermal method. The characterization of transmission electron microscopy (TEM) indicates that the as prepared composite consists a core particle located within a well-defined shell with a clear gap between the two, forming a unique yolk-shell structure. The optimal sulfur-doped CuFe2O4@ZnFe2O4 yolk-shell heterostructure presents a photocurrent of 35.42 μA·cm−2, which is five times higher than undoped sample of 7.06 μA·cm−2. Photoelectrochemical method are used to analyze the behavior of photoinduced charges to reveal the structure-property relationship. The built-in electric field of heterojunctions effectively improves the separation of photoinduced charges, and the surface sulfur ions have an enrichment effect on photoinduced electrons. The yolk-shell heterostructure exhibits superior activity for photocatalytic reduction of nitrobenzene showing a selectivity of 99% and yield of 60.6%.