Tuning of Photocatalytic Performance of CeO2-Fe2O3 Composite by Sn-doping for the Effective Degradation of Methlene Blue (MB) and Methyl Orange (MO) dyes

Abstract

One of the major class of pollutants used among textiles, medicines, plastics are organic dyes. Water pollution due to the industrial exhaust of large amount of these colouring materials are a major threat to our environment. Conventional methods of water treatment are not effective as these chemicals are not easily degradable. Sn-doped 1:2 CeO2-Fe2O3 nanocomposite with varying Sn content was prepared by thermal decomposition method for efficient degradation of MB and MO dyes under visible light. The phase composition and morphology were controlled by varying Sn content. 5% Sn doped 1:2 CeO2-Fe2O3 nanocomposite achieved nearly complete degradation for 10-50 mg/L MO solution and the maximum degradation efficiency obtained for MB solution is 93.54- 94.65 % for 10-30 mg/L MB solution. The optimized photocatalyst degraded MO more efficiently than MB solution. A smaller crystallite size of 12 nm was obtained. Incorporation of Sn4+ ions in CeO2 lattice improved the catalytic activity of CeO2-Fe2O3 composite by altering the fermi level of CeO2, facilitating charge separation. The influence of factors such as, exciton generation under solar irradiation, charge recombination rate, surface charge availability were illustrated. The long term stability and reusability of the catalyst composite towards photo degradation reaction unveil the industrial significance of the metal oxide composite.