Manpreet KaurVibha2020-05-212020-05-212020http://krishikosh.egranth.ac.in/handle/1/5810146249Role of nanoferrites and their graphene Oxide (GO) composites as enzyme mimics and photocatalysts is a thrust area of research. In the present work, pure and ternary doped ferrite nanoparticles (NPs) of Mn, Co and Cu and their GO nanocomposites (NCs) were synthesized using facile sol-gel and sonication method respectively. FT-IR spectra and XRD patterns confirmed the formation of single phase ferrite NPs, GO sheets and their NC. Maximum saturation magnetization value was 65.0 emu/g for ternary ferrite NPs having formula Mn0.4Co0.4Cu0.2Fe2O4. SEM and TEM micrographs revealed the porous nature and fabrication of ferrite NPs onto GO sheets in the NCs. The larger surface area of NCs as compared to pristine NPs was confirmed by BET studies. Synthesized NPs, GO and NC were evaluated as peroxidase, superoxide dismutase (SOD) and polyphenol oxidase (PPO) enzyme mimics. MnFe2O4 NPs exhibited maximum peroxidase and PPO mimic activity, whereas SOD mumic activity was shown by CuFe2O4 NPs. Observed results were explained on the basis of structure of ferrite NPs. Synergistic adsorption and photocatalytic potential of ferrite NPs, GO and NC was studied using malachite green and methylene blue as model compounds. The adsorption data was best fitted into Langmuir adsorption isotherm and followed pseudosecond- order kinetic model. The NC exhibited better adsorption and photocatalytic activity as compared to ferrite NPs under visible light. The degradation mechanism was proposed on the basis of mass spectrometric analysis of products formed during photodegradation.enThesis