Synthesis And Photocatalytic Activity Of Graphitic Carbon Nitride Based Nanocomposites

Semiconductor photocatalysts have great potential in tackling of solving clean energy demand and environmental pollution. Among various photocatalysts, graphitic carbon nitride?CN? with a comparable ?-conjugated graphite structure has attracted considerable attention owing to its favorable visible light harvesting capability.CN materials could be exfoliated by sulfuric acid into graphitic carbon nitride nanosheets?CN-NSs? for increasing mobility of charge carriers. Moreover, the liquid-phase exfoliation process maked CN-NSs catalysts more water-dispersible, which was favorable for assembling on support materials when constructing heterostructures.But CN-NSs catalysts exhibited a remarkable blue shift of the absorption edge because of quantum confinement effect.To overcome these problems, it is desirable to extend the delocalization of the ? electrons by grafting benzene in the skeleton of CN,Which have been made to reduce the recombination losses and extend the light responsive region of CN catalysts.Then CNX catalysts ware exfoliated into CNX-NSs materials, the resulting that blue shift phenomenon of CN-NSs catalysts could be improved by grafting benzene The CNX-NSs nanosheets ware measured by AFM, displaying a thickness of 0.66-0.88 nm.Because CNX-NSs materials and anatase titanium dioxide?TiO₂? matched in band structure, this paper prepared CNX-NSs/TiO₂ composite materials by ultrasonic than solvent evaporation method, and the optimal mass ratio of TiO₂ to CNX-NSs was 3:1 by comparing the photocatalytic activity of degradation RB. TiO₂ particles dispersed on the surface of CNX-NSs nanosheets,which can be observed in the TEM figure, the heterojunction between CNX-NSs and TiO₂ materials could transfer electron form CNX-NSs materials conduction band to TiO₂ materials conduction band, Which improved the separation efficiency of electronic-hole pair, the photocatalytic activity of degradation rhodamine B?RB? increased significantly.Finally,this paper alse confirms mainly species is super oxygen anion?O₂^-?, holes?h+? and hydroxyl radical?·OH? played a little role in photocatalysis process by Trapping test.This paper prepared CNX-NSs/RGO composite materials by photocatalytic reduction method, Because RGO materials had a advantage of excellent electrical conduction ability, so it could transfer electron of CNX-NSs materials quickly and improve the quantum efficiency, the experimental results showed that the photocatalytic activity of CNX-NSs/RGO composite materials for degrading methylene blue?MB?was Significantly improved compared to the photocatalytic activity of CNX under simulated-sunlight and visible light illumination, besides, the optimal mass content of RGO was 20%.Finally, this paper alse confirms mainly species is hydroxyl radical?·OH?, and ·OH species were transformed from H₂O₂ that was generated from reaction of electronic?e-? and oxygen?O₂? on the surface of photocatalyst, holes?h+? played a little role in photocatalysis process by Trapping test and H₂O₂ detection.