Facile synthesis of Super-paramagnetic Au @alpha-Fe2O3 hybrid nanoparticle and its assembly on graphene substrate for visible light Photo-catalysis

We report a simple interface modified strategy to self-assemble the as-synthesized Au@Fe2O3 nano structures by facile chemical synthesis route on graphene substrate (AFG) fo tau substrate mediated photo-catalytic dye degradation. The substrate modification, film formation, photo induced charge transfer mechanism and the physico-chemical properties of the AFG has been systematically analysed using different analytical techniques. The alteration in light absorption capacity and band gap of the hybrid with respect to the individuals have been observed using diffuse reflectance spectroscopy. Moreover, the broad absorption in the visible range and squeeze in band gap of the hybrid from 2.3 to 1.97 eV confirms the ability of the hybrid and the intention of hybridization for visible light-responsive photo-catalysis. Additionally, interesting superparamagnetic behaviour of the hybrid and its magnetic separation ability has been explored. Further, the applicability, repeatability and versatility of this AFG hybrid material in catalytic degradation of different dyes in presence of visible light have been analysed. This AFG catalyst exhibits excellent photocatalytic activity against the decolouration of the both cationic and anionic dyes. A systematic study in the photo-catalytic degradation behaviour, kinetic of degradation and the postulated mechanism has been proposed.