ZnO–Al2O3–CeO2–Ce2O3 mixed metal oxides as a promising photocatalyst for methyl orange photocatalytic degradation

Abstract

In this research article, ZnO–Al2O3–CeO2–Ce2O3 mixed metal oxides phases were prepared by calcination of Zn–Al/Ce–CO3 layered double hydroxides (LDH) precursors, and evaluated for the photocatalytic degradation of methyl orange (MO) as a model textile dye from aqueous solution under UV irradiation. First, Zn–Al–CO3 and a series of Zn–Al/Ce–CO3 with different Ce content (5, 10, 15, 20%) were synthesized through co-precipitation method at Zn/(Al+Ce) molar ratio (r) of 3, then subjected to calcination at 500 °C for 6 h. Samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray analysis and pH point of zero charge. The experimental results of the photodegradation reveal that the photocatalyst developed from Zn–Al–Ce10%-CO3 LDH exhibits the highest photocatalytic activity, with a degradation efficiency of 99.8% after 300 min of irradiation. This performance was mainly ascribed to the presence of difference state of Ce, leading a highest separation efficiency of electrons and holes. The recycling tests suggests a much high photostability and reusability of the photocatalyst.