In situ construction of hybrid MnO2@GO heterostructures for enhanced visible light photocatalytic, anti-inflammatory and anti-oxidant activity
Graphene oxide with a sheet like structure is extremely attractive especially in the field of photocatalysis as it promotes charge separation and has a high surface area. In this study, visible light active MnO2/GO nanocomposites were constructed by an in situ solution phase approach with an excellent photocatalytic response. The as-synthesised MnO2/GO nanocomposites were systematically characterised by various spectroscopic and microscopic techniques. Morphological characterisation displayed that the MnO2 nanoparticles are well anchored over the whole surface of the graphene oxide sheets. The photocatalytic experiments suggested that the MG0.4 nanocomposite showed the best photocatalytic response – almost 94% of rhodamine-B (Rh-B) dye was degraded in 65 min. The higher efficiency in the photocatalytic performance of the MnO2/GO composites is attributed to the enhanced separation of the photogenerated charge carriers in the composite. We are optimistic that our findings can unlock a new direction for the photocatalytic application of MnO2/GO composites. The as-synthesised MnO2/GO nanocomposites were also evaluated for antioxidant activity using an in vitro DPPH radical assay. Considerable in vitro antioxidant activities in a concentration-dependent manner were recorded. Interestingly, the nanocomposite MG0.4 showed a more elevated scavenging efficiency than GO in DPPH tests. Furthermore, the nanocomposites were investigated for their in vitro anti-inflammatory activity using the inhibition of protein denaturation method. The protein denaturation assay shows the prominent anti-inflammatory activity of the as-synthesised materials.