Invited paperEnhanced visible light photocatalytic performance of g-C3N4/CuS p-n heterojunctions for degradation of organic dyes

A novel g-C3N4/CuS p-n heterostructured photocatalyst has been fabricated through an in situ synthesis technique. The samples were characterized through X-ray diffraction, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and UV-vis spectroscopy. And the results indicated that CuS nanoparticles were closely anchored on the surface of g-C3N4 with good dispersion. The g-C3N4/CuS heterojunctions exhibited enhanced photocatalytic performance in degradation of RhB and MB than that of pure g-C3N4 and CuS, and the selected sample of g-C3N4/CuS-2 displayed the best photocatalytic activity. The degradation rates of RhB and MB with g-C3N4/CuS-2 photocatalyst were 8.914 and 13.543 times higher than that of pure g-C3N4, and 3.023 and 6.373 times higher than that of pure CuS, respectively. The enhancement of photocatalytic activity may be ascribed to the matched overlapping band structure and the interaction between CuS and g-C3N4. The interaction between g-C3N4 and CuS would not only improve the optical absorption property of g-C3N4, but also create more interface for the efficiently transfer of photo-generated electron-hole pairs to restrict the recombination, which was proved by the photoluminescent spectra. Moreover, a possible photocatalytic mechanism has been tentatively proposed according to the experimental results.

Schematic illustration of proposed mechanism for the photocatalysis of the g-C3N4/CuS heterojunctions under visible light irradiation211