Novel Bi_2S_3/BiOCl photocatalysts were successfully synthesized via a facile biomoleculeassisted solvothermal method and biomolecule L-cysteine was used as the sulfur source.The structures,morphology,and optical properties of the synthesized samples were characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Raman spectroscopy,transmission electron microscopy(TEM),and UV-vis diffuse reflectance spectroscopy(DRS).The presence of Bi_2S_3 in the Bi_2S_3/BiOCl composites could not only improve the optical properties but also enhance the photocatalytic activities for the degradation of Rhodamine B(Rh B) under visible-light irradiation(λ>420 nm) as compared with single Bi_2S_3 and BiOCl.Especially,the sample displayed the best performance of the photodegradation when the feed molar ratio of BiCl_3 and L-cysteine was 2.4:1,which was about 10 times greater than that of pure Bi OCl.The enhanced photocatalytic activities could be ascribed to the effective separation of photoinduced electrons and holes and the photosensitization of dye.Moreover,the possible photodegradation mechanism was also proposed,and the results revealed that the active holes(h+) and superoxide radicals(·O_2^-) were the main reactive species during photocatalytic degradation.
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