Enhanced visible-light-responsive photocatalytic property of PbS-sensitized K4Nb6O17 nanocomposite photocatalysts

PbS-loaded K4Nb6O17 nanocomposite photocatalysts (hereafter designated as PbS@K4Nb6O17) were prepared via a reverse microemulsion method. The nanocomposite materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray fluorescence spectrometer, ultraviolet–visible diffuse reflection spectra, photoluminescence measurement and X-ray photoelectron spectroscopy. The nano-semiconductor PbS@K4Nb6O17 composites have the layered structure and the band gaps of the two semiconductors couple. The nanocomposite PbS@K4Nb6O17 exhibited a strong photocatalytic activity for degradation of Rhodamine B (hereafter referred as RhB) under visible light irradiation. Moreover, the nanocomposite PbS(25 wt.%)@K4Nb6O17 shows the highest photocatalytic activity, the decomposition rate of RhB solution is about 71% after 120 min under visible light irradiation, which is over that of the pure K4Nb6O17 and pure PbS particles. The nanocomposite photocatalysts proved to be fairly photostable through the recyclability experiments. The mechanism of separation of the photogenerated electrons and holes at the PbS@K4Nb6O17 was discussed.