Enhanced visible light photocatalytic activities of template free mesoporous nitrogen doped reduced graphene oxide/titania composite catalysts

• Simultaneous doping of nitrogen into graphene and TiO2 has been done.
• Incorporation of graphene and nitrogen reduced the band gap.
• Tremendous visible light activity was observed for N-[5% rGO-TiO2] composite.
• Recombination of e−/h+ was retarded by nitrogen decorated rGO-TiO2 composites.
• N-rGO and N-TiO2 in the composites acted as charge transporter and red shifter.

We report a new photocatalytic material to address the twin issues namely recombination of electron/hole pairs and visible light inactivity of the titania based photocatalysts. A template free hydrothermal method was adapted to synthesize mesoporous nitrogen doped reduced graphene oxide/titania composite catalysts (N-[x% rGO-TiO2] where x = 2.5, 5, 7.5 and 10%). The detailed physicochemical studies of the catalysts were done and correlated with their photocatalytic activities. Simultaneous nitrogen doping on both reduced graphene oxide and titania was confirmed by X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the synthesized composite catalysts were evaluated towards the photodegradation of organic dyes namely methylene blue and congo red under visible light irradiation. Among them, the composite N-[5% rGO/TiO2] showed the highest photocatalytic activity. Doping of nitrogen makes graphene a better charge transporter whereas nitrogen in TiO2 lattice makes it visible light active (red shift).

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