The induced synthesis of mixed phase niobate by Cu doping and its photocatalytic property

► Cu-doped KNb3O8 photocatalysts were prepared by a simple solid-state method. ► Cu doping can induce the formation of mixed phase niobates with KNb3O8 and K6Nb10.8O30. ► Cu doping and mixed phase niobates synergistically enhanced the photocatalytic activity.