Ce-Doped CuMgAl Oxide as a Redox Couple Mediated Catalyst for Visible Light Aided Photooxidation of Organic Pollutants

Ce doped CuMgAI (10:40:50)-mixed metal oxides with different Ce contents (0.5-2.0 wt %) were synthesized by a simple coprecipitation method followed by doping with cerium. Then, their structural, optical, and morphological properties were characterized. The results revealed that the surface areas of the samples are very high (similar to 138 m(2)/g), which is an important property of a photocatalyst. All the doped samples exhibited enhanced photocatalytic activity compared to the undoped sample for degradation of a model organic pollutant, 2,4-dichlorophenol (2,4-DCP). The amount of Ce doping in the material played an important role in the photocatalysis. Among the prepared samples, 1.0 wt % Ce doped sample exhibited highest photocatalytic activity due to lowest recombination of photogenerated electron holes. The developed Ce4+/Ce3+ redox couple is a special feature of the catalytic design, which mainly facilitates separation of photogenerated electrons and holes. The catalytic steps on conduction band and valence band of the photocatalyst are favorable to form Ce4+/Ce3+ redox couples in continuous cycles and, hence, accelerate the photocatalytic process effectively. Moreover, activity of the catalyst was investigated under various light irradiations, such as UV, visible, and UV-vis light. The rate of the photodegradation is found to be 3.7 times and almost 5 times higher by using the 1.0 wt % Ce doped sample compared to the undoped sample under visible light and UV-vis light irradiation, respectively. A possible mechanism of photocatalysis and pathways of degradation of 2,4-DCP are also discussed.