摘要

ZnGa2O4, ZnGa2O4:Eu3+, and ZnGa2O4:Dy3+ phosphors were synthesized using a solid state method and their photocatalytic properties were measured in the degradation of rhodamine B under ultraviolet light. The photocatalytic activity ZnGa2O4 decreased with Eu3+ doping, but was enhanced by Dy3+ doping. The Eu3+ ions acted as recombination centers, increasing the recombination of photogenerated electrons and holes, resulting in poor photocatalytic activity and a short persistent luminescence. Dy3+ ions acted as trap centers, which decreased the recombination of photogenerated electrons and holes, resulting in good photocatalytic activity and a long persistent luminescence. Thermoluminescence measurements demonstrated that Eu3+ doping decreased the trap concentration, while Dy3+ doping increased the trap concentration. We propose that an inherent relationship exists between photocatalytic activity and persistence of luminescence. A larger amount of traps results in improved photocatalytic activity and excellent persistent luminescence.