Synthesis and application of novel α-Fe₂O₃/graphene for visible-light enhanced photocatalytic degradation of RhB

Hematite α-Fe₂O₃ nanoparticle synthesis via a facile and eco-friendly hydrothermal method has been hybridized by different loading of graphene obtained by the pyrolysis of biopolymers (alginate, chitosan and carrageenan). The resulting α-Fe₂O₃-Gr catalyst shows a high catalytic activity of ~98% toward RhB degradation under visible light irradiation. The existence of N and S heteroatoms on the surface of the graphene affects the size of nanoparticles and the specific surface area in the α-Fe₂O₃-Gr, with a negative effect on catalytic performance. Electron Spin Resonance (ESR) studies showed that the hydroxyl radical [rad]OH was the main reactive species responsible for the degradation of RhB. The reusability of α-Fe₂O₃-Gr was studied and the catalyst kept good stability and high activity over four cycles with no change in the morphology of the catalysts. Interestingly, incorporation of graphene into hematite nanoparticles resulted in superior photocatalytic activity compared to α-Fe₂O₃ loaded on carbon nanotubes, active carbons and biochar.