Achieving ideal photocatalytic systems by mimicking Z-scheme mechanism in natural photosynthesis results in highly efficient artificial photosynthesis. A new oxynitride-based solid state Z-scheme photocatalytic system containing (GaxZn(1-x))(NxO(1-x)) and Nb3.49N4.56O0.44 was constructed. Nb-3.49 N4.56O0.44/(GaxZn(1-x))(NxO(1-x))(6.0) exhibits the highest rate for complete reduction of Cr(VI) within 30 min under simulated sunlight irradiation as well as extremely high apparent quantum efficiency of 68% at 350 nm 24.4% at 420 nm for photocatalytic water oxidation: A similar solid state Z-scheme photocatalytic system was also obtained when. compositing Nb3.49N4.56O0.44 with TaON. It's expected that Nb3.49N4.56O0.44 can also be composed with other oxynitride semiconductor to construct more oxynitride-based solid state Z-scheme photocatalytic systems. (C) 2015 Elsevier B.V. All rights reserved.