Walnut-like ZnO@Zn2TiO4 multicore-shell submicron spheres with a thin carbon layer: Fine synthesis, facile structural control and solar light photocatalytic application

Abstract

In this study, we propose a fine fabrication method of walnut-like ZnO@Zn2TiO4 multicore-shell submicron spheres for the solar light-responsive photocatalysis. Poly(methacrylic acid/ethylene glycol dimethacrylate) [poly(MAA/EGDMA)] microspheres were used as sacrificial template to create the hierarchically-structured hybrid metal oxide spheres with a thin carbon layer. Heterogeneous multicore-shell structure like a walnut depends on the monomer ratio of poly(MAA/EGDMA) microspheres. The thin carbon layer formed on the surface of ZnO nano-grains can cause visible light response and effectively impede the recombination of photo-generated electron-hole. When the walnut-like ZnO@Zn2TiO4 multicore-shell submicron spheres with a thin carbon layer are tested as photocatalysts under solar light, the photodegradation of organic dye of above 93% is exhibited for 1 h due to the multiple light scattering originated from the unique structure and a coexistence of ZnO and Zn2TIO4.