A new oxynitride-based solid state Z-scheme photocatalytic system for efficient Cr(VI) reduction and water oxidation

• New all oxynitride-based solid state Z-scheme photocatalytic systems were constructed for the first time.
• Nb3.49N4.56O0.44/(GaxZn1-x)(NxO1-x)(6.0) exhibits the highest rate for complete Cr(VI) reduction and extremely high efficiency for water oxidation.
• A similar solid state Z-scheme photocatalytic system was also obtained when compositing Nb3.49N4.56O0.44 with TaON.

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 (GaxZn1-x)(NxO1-x) and Nb3.49N4.56O0.44 was constructed. Nb3.49N4.56O0.44/(GaxZn1-x)(NxO1-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.

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