Catalytic Oxidation of Volatile Organic Compounds Alone or in Mixture over Mg4Al2−xCex Mixed Oxides

Abstract

This study investigates Ce-containing MgAl layered double hydroxides (LDH), focusing on its structural and catalytic properties. Mg4Al2−xCex (x = 0; 0.4; 0.8; 2) hydrotalcite-like compounds were prepared using the co-precipitation method. The effects of cerium content and calcination temperature on the structural and catalytic properties of Ce-containing MgAl LDH were investigated. The samples were characterized by XRD, BET, Raman, XPS, and DTA/TGA techniques. The catalytic activity of the resulting compound in n-butanol oxidation was studied. Increasing the calcination temperature (from 280 to 500 °C) caused changes in the structural, textural, and reducibility properties. The Mg4Al2−xCex LDH structure series (calcined at 280 °C) exhibited the highest catalytic activity, especially for x = 2. The material’s properties improved with increased Ce content, allowing complete butanol conversion below 280 °C. The formation of active sites occupied by cerium within the LDH structure, along with its reducibility properties, contributed to the material’s performance. The Ce3+/Ce4+ redox couple in the external layers enhanced O2− diffusion and their activation into nucleophilic species, facilitating butanol transformation. Adding water vapor to the reaction mixture slightly decreased the butanol oxidation, while the presence of ethyl acetate and butanol together exhibited a mutual inhibitory effect, with butanol demonstrating a more prominent influence.