Unprecedented enhancement in visible-light-driven photoactivity of modified graphitic C3N4 by coupling with H2WO4

•H2WO4 coupling g-C3N4 are successfully prepared for the first time.•Simple synthesis method was adopted.•10% H2WO4/g-C3N4 catalyst shows 50 times higher activity than the pure one.•Superior stability even after nine successive runs.•Synergistic interaction plays very important role in the degradation of RhB.

The modified graphitic carbon nitride (g-C3N4) nanosheets by coupling with H2WO4 are fabricated via an easy, mild and environmental-friendly impregnation method for the first time. Compared with bare g-C3N4 and H2WO4, the H2WO4/g-C3N4 composite shows significant enhancement in the visible-light-driven photoactivity toward the degradation of Rhodamine B (RhB). It is found that 10 wt.% H2WO4/g-C3N4 exhibits the best photocatalytic performance, with around 20 times higher activity than that of pure g-C3N4 nanosheets. The remarkably increased performance is mainly attributed to the existing synergistic interaction between H2WO4 and g-C3N4. The strong interaction could reduce the photoinduced electron–hole recombination and further improve the photocatalytic activity. Additionally, O2− is the dominating reactive species for the degradation of RhB, which has been confirmed by the radical scavengers tests. The synthesized photocatalysts present super stability even after nine successive runs. Considering the low-cost, easy preparation process and ultra-high activity, the H2WO4/g-C3N4 photocatalyst can be served as a promising candidate for environment cleaning and waste water treatment.

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