One-step fabrication of g-C3N4 nanosheets/TiO2 hollow microspheres heterojunctions with atomic level hybridization and their application in the multi-component synergistic photocatalytic systems

•The g-C3N4 NSs/TiO2 HMSs was successfully fabricated in the assistance of HCMSs.•HCMSs act as both dispersant and structure-directing agent in catalyst preparation.•Synergistic photocatalytic effects in the composite pollution systems were studied.•Total reaction efficiencies are improved in the synergistic photocatalytic systems.•Synergistic photocatalytic mechanisms in composite pollution systems were discussed.

In this paper, graphitic carbon nitride nanosheets/titanium dioxide hollow microspheres heterojunctions (g-C3N4 NSs/TiO2 HMSs) with excellent photocatalytic activity were successfully fabricated by a simple one-step synthesis strategy in the assistance of hydrothermal carbon microspheres. Hydrothermal carbon microspheres act as both dispersant and structure-directing agent for the simultaneous construction of graphitic carbon nitride nanosheets and titanium dioxide hollow microspheres. The synergistic photocatalytic effects in the 4-fluorophenol/hexavalent chromium [4-FP/Cr(VI)] and hexavalent chromium/trivalent arsenic [Cr(VI)/As(III)] multi-component composite pollution systems were studied by using as-prepared g-C3N4 NSs/TiO2 HMSs under different pH conditions. Interestingly, the efficiencies of 4-FP degradation, Cr(VI) reduction, and As(III) oxidation were simultaneously improved in the 4-FP/Cr(VI) and Cr(VI)/As(III) multi-component synergistic photocatalytic systems relative to the single-component photocatalytic systems. The synergistic photocatalytic mechanisms in the 4-FP/Cr(VI) and Cr(VI)/As(III) multi-component synergistic photocatalytic systems were systematically discussed.

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