Enhanced visible light photocatalytic activity in SnO2@g-C3N4 core-shell structures

SnO2@g-C3N4 core-shell structures were successfully synthesized by simple calcination of SnO2 microspheres and urea in a muffle furnace. The investigation of morphologies and microstructures showed that g-C3N4 was wrapped tightly on the surface of SnO2 microspheres with large intimate interface contact areas between the g-C3N4 shells and SnO2 cores. The X-ray photoelectron spectroscopy results and photoluminescence spectra demonstrated that the intimate interface contacts could facilitate the transfer and separation of the photogenerated charge carriers at their interface, thus the recombination of the photogenerated electron-hole pairs was impeded. The photocatalytic activity of the synthesized composites was evaluated by the photodegradation of methyl orange under visible light irradiation. It was found that SnO2@g-C3N4 exhibited higher photodegradation rate (k = 0.013 min−1) than that of g-C3N4 (k = 0.008 min−1) and pure SnO2. The enhanced photocatalytic activity could be attributed to the synergic action of SnO2 and g-C3N4.