Abstract:

Using melamine and ammonium molybdate tetrahydrate as precursors,a novel MoO₃/g-C₃N₄ composite photocatalyst was prepared by hydrothermal method.The samples were characterized by X-ray diffraction（XRD）,infrared spectroscopy （FT-IR）,scanning electron microscopy（SEM）,X-ray photoelectron spectroscopy（XPS） and ultraviolet-visible diffuse reflectometer（DRS）.Characterization results showed that the optical absorption of the composites was enhanced when the rodlike MoO₃ was loaded on the layered g-C₃N₄ surface.The experiment of photocatalytic degradation of methylene blue（MB） solution by material visible light showed that the heterojunction produced by MoO₃ and g-C₃N₄ had better absorption light intensity and catalytic degradation performance,especially the 5%（mass fraction） MoO₃/g-C₃N₄ composite photocatalytic degradation rate was the best,reaching 95.7%,higher than that of pure MoO₃ and g-C₃N₄.Free radical and hole trapping experiments show that ·O₂^- was the main substance in photocatalytic reaction.The MoO₃/g-C₃N₄ composite exhibited excellent stability in four reaction cycles.

Key words: molybdenum trioxide, carbon nitride, visible light, photocatalysis