Synthesis of nitrogen-doped graphene–ZnO nanocomposites with improved photocatalytic activity

•Synthesis of nitrogen-doped graphene–ZnO nanoparticle composites by a facile method.•N-graphene–ZnO NPs exhibit higher photodegradation activity than pure ZnO NPs.•The optimum loading amount of N-graphene is 2 wt% in N-graphene–ZnO nanocomposite.•N-graphene–ZnO NPs possess a better recyclability and stability than ZnO NPs.

A series of nitrogen-doped graphene–ZnO (NG–ZnO) nanocomposites with different weight addition ratios of nitrogen-doped graphene have been prepared via a facile sol–gel method. ZnO nanoparticles (NPs) in diameter of 8–20 nm were distributed on the surface of NG, which exhibit higher photocatalytic activity, recyclability and stability than ZnO NPs toward degradation of methyl orange in water under ultraviolet light irradiation. The ZnO NPs with 2 wt% NG content exhibited the highest photodegradation efficiency of methyl orange (96.4% in 15 min), which was about 1.23 times of pure ZnO NPs (78.2% in 15 min).

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