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

Cu-doped KNb₃O₈ photocatalysts were prepared using a simple solid-state method. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectrum. XRD and SEM analyses suggest that Cu doping can induce the formation of the compound K₆Nb_10.8O₃₀ with tungsten-bronze structure and the relative content of K₆Nb_10.8O₃₀ in the Cu-doped samples increased with increasing Cu doping amount. When the Cu doping amount reaches 2 wt.%, the as-prepared sample is mainly composed of K₆Nb_10.8O₃₀. The photocatalytic properties of the catalysts were evaluated using the degradation of acid red G. The results showed that Cu-doping significantly increased the photocatalytic activity of the KNb₃O₈ catalyst. The optimum dopant concentration range of Cu was found to be 0.3-1 wt.%. The synergistic effect of Cu doping and mixed phase niobate compounds is responsible for the enhanced photocatalytic activity.