Nanostructured bi-phasic TiO2 nanoparticles grown on reduced graphene oxide with high visible light photocatalytic detoxification

•RGO-TiO2 overcomes the limitations of existing monophasic/multiphase photocatalyst.•Novel photocatalyst system having biphasic titania coupled with graphene developed.•The facile ex-situ synthesis process adds to the novelty of the present work.•RGO-TiO2 (M) shows better performance in detoxification and bacterial disinfection.

Graphene with inherent high mobility for charge carriers is known to complement the photo-activity of metal oxide-graphene nanocomposite. Also mixed phase (biphasic) metal-oxides shows reasonably improved performance compared to its monophasic counterparts. In this present report, we synthesize graphene-mixed phase titania nano-composite by ex-situ hydrothermal method and characterize by various tools like, XRD, HR-TEM, EDX, XPS, Raman, FTIR, UV and PL. The impacts of synergy of the mixed phase titania (TiO2 (M), with suitable phase ratio of anatase/rutile for high visible light activity) and reduced graphene oxide (RGO, with high affinity/conductivity for photogenerated carriers) in such a coupled system is expected to be positive. This is assessed both by photocatalytic degradation test with methylene blue as one of probe pollutant and in vitro antibacterial activity evaluation for both gram positive (B. subtiles) as well as gram negative (E. coli) bacteria. The wide spectrum antibacterial photo-activity along with high photo-detoxification activity of the RGO-TiO2 (M) compared to mixed phase TiO2 (M) makes it unique.

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