Decoration of mesoporous Co3O4 nanospheres assembled by monocrystal nanodots on g-C3N4 to construct Z-scheme system for improving photocatalytic performance

Highlights: • Co₃O₄/g-C₃N₄ Z-scheme system was constructed by mesoporous Co₃O₄ and g-C₃N₄. • Co₃O₄/g-C₃N₄ Z-scheme system showed a good photocatalytic activity. • The mesoporous structure obviously improved separation efficiency of charge carriers. The Co₃O₄/g-C₃N₄ Z-scheme system is constructed by decoration of mesoporous Co₃O₄ nanospheres assembled by monocrystal nanodots on the surface of g-C₃N₄, which dramatically improves the photocatalytic activity for degrading tetracycline hydrochloride (TC) compared with single g-C₃N₄. The microstructure investigations evidence the mesoporous structure and enlarged specific surface area of Co₃O₄/g-C₃N₄ Z-scheme system, which implies the increase of surface active sites and adsorption ability for reactant molecules. Moreover, by virtue of analyzing physical and photoelectrochemical properties, it evidences that the decoration effect of mesoporous Co₃O₄ nanospheres on the surface of g-C₃N₄ obviously improves the transfer and separation efficiency of charge carriers between two phase interfaces and broadens light harvest range. These important factors are beneficial to enhancing photocatalytic activity of Co₃O₄/g-C₃N₄ Z-scheme system. In addition, the photocatalityc reaction mechanism is also revealed in depth.