Synergistic effect of hybrid Ce3+/Ce4+ doped Bi2O3 nano-sphere photocatalyst for enhanced photocatalytic degradation of alizarin red S dye and its NUV excited photoluminescence studies

Highly spherical structured Ce3+/Ce4+ doped Bi2O3 nanosphere photocatalyst was prepared by simple solid state reaction route. The crystallite phase of a photocatalyst plays an important role on its activity. Hence, the phase of the catalyst is suitably tuned by varying cerium concentration and calcination temperature. From the experimental data it is evident that, 9 wt% cerium doped Bi2O3 calcinated at 600 degrees C showed better photocatalytic performance for the degradation of Alizarin red S dye. The enhanced performance of this optimized catalyst is due to synergistic effect by the presence of inter convertible Ce3+/Ce4+ oxidation states and mixed alpha-beta phase Bi2O3. Addition of EDTA-2Na and radical scavengers (Benzoquinone, t-BuOH) decreased the photocatalytic efficiency, which indicates that, the presence of O-2, O-2(-center dot) and % OH radicals and their significant role in the degradation of ARS dye. A plausible mechanism and degradation pathway of ARS degradation has been proposed.