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

Highlights: • Novel SnO₂@g-C₃N₄ core-shell structures were successfully synthesized. • The core-shell structures exhibited enhanced visible light photocatalytic activity. • The enhanced photocatalytic activity was due to synergic action of SnO₂ and g-C₃N₄. - Abstract: 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.