Cerium is a rare earth element of the lanthanide series (atomic no. = 57– 71) of the periodic table. Among the various rare earth metals, cerium granted a hugeattention towards scientific community due to its catalytic antioxidant property. Usually, antioxidants protect cells from oxidative damage, mediated by ‘reactive oxygen species’ (ROS), which include free radicals such as superoxide anion (O2•-), hydroxyl radical (•OH), singlet oxygen (1O2) and non-free radical species like hydrogen peroxide (H2O2). Cerium, in both salt and oxide forms, cycles between the cerous (Ce3+) and the ceric (Ce4+) oxidation states. CeO (III) is fast oxidized to CeO (IV) by (ROS) and by that CeO (III) successfully neutralizes ROS. Again CeO (IV) is slowly reduced by ROS to slip back to CeO (III), leaving oxygen vacancies in the CeO crystal lattice that becomes further reactive towards ROS (Kuchibhatla et al., 2012)(Lee et al., 2013). Thus, cycle of CeO between +3 and +4 states can uninterruptedly break down ROS. In the
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From this spectrophotometric data, band gap energy Eg between valence and conduction bands of the nano-ceria particles was measured, using Tauc’s equation, the principle of which has been described in subsection 2.4 & 2.5 of ‘Materials and Methods’chapter. Results and discussion: The UV-Vis absorption spectrum of CeONP suspension showed a peak at around 270 nm (fig.3.1). Nature of the spectrum conformed well the characteristic UV-Vis spectrum of nano-ceria, prepared by other methods (Das et al., 2007)(Kim et al., 2012)(Deshpande et al.,
From this spectrophotometric data, band gap energy Eg between valence and conduction bands of the nano-ceria particles was measured, using Tauc’s equation, the principle of which has been described in subsection 2.4 & 2.5 of ‘Materials and Methods’chapter. Results and discussion: The UV-Vis absorption spectrum of CeONP suspension showed a peak at around 270 nm (fig.3.1). Nature of the spectrum conformed well the characteristic UV-Vis spectrum of nano-ceria, prepared by other methods (Das et al., 2007)(Kim et al., 2012)(Deshpande et al.,