Enhanced photocatalytic activity of sponge-like ZnFe2O4 synthesized by solution combustion method

A kind of cubic ZnFe2O4 with spinel structure was synthesized by an improved solution combustion method via a facile and environmentally friendly pathway and their photocatalytic activity under visible light radiation was investigated. The particle synthesized under the ignition temperature of 573 K has a pure phase. While a small amount impurities, α-Fe2O3 and ZnO, were formed in the sample during the combustion process at higher ignition temperature of 623 K. The synthesized ZnFe2O4 has a sponge-like porous structure and wide absorption in the visible-light region. The impurities α-Fe2O3 and ZnO formed in the sample probably enhance the reduction and oxidation ability and promote the separation of photo-generated electrons and holes. Comparing with ZnFe2O4 synthesized by the conventional solid state reaction, the ZnFe2O4 derived by solution combustion method showed the better photocatalytic activity under visible light radiation.