Remarkable enhancement in visible-light absorption and electron transfer of carbon nitride nanosheets with 1% tungstate dopant

Highly efficient [WO₄]^2--doped graphitic carbon nitride (g-C₃N₄) nanosheets were fabricated via a facile and simple method using dicyandiamide and sodium tungstate as precursors. Various analytical techniques were carried out to characterize the [WO₄]^2--doped g-C₃N₄ photocatalyst. The results illustrated that [WO₄]^2- intercalated into the interlayers of g-C₃N₄ nanosheets and bridged with g-C₃N₄ nanosheets through the unoccupied orbital of tungsten in [WO₄]^2- species and the lone-pair electrons of nitrogen in tris-s-triazine structure, resulting in the enhanced visible light absorption and the electronic structural modulation of g-C₃N₄. More significantly, the [WO₄]^2--doped g-C₃N₄ catalyst exhibited greatly enhanced photocatalytic activity and superior stability for the degradation of organic pollutants (including Rhodamine B, methyl orange and methylene blue) under visible light irradiation. In addition, the underlying photocatalytic reaction mechanism was investigated by the controlled experiments using radical scavengers.