Effect of calcination temperature on the structure and performance of CeOx-MnOx/TiO2 nanoparticles for the catalytic combustion of chlorobenzene

In this study, MnOx/TiO2, CeOx/TiO2, and CeOx-MnOx/TiO2 catalysts were prepared by the homogeneous precipitation method. The effect of calcination temperature on the structure and catalytic performance of CeOx-MnOx/TiO2 mixed oxide catalyst in the catalytic combustion of chlorobenzene was investigated. The samples were characterized by X-ray diffraction, nitrogen adsorption-desorption, transmission electron microscopy, Raman spectra, hydrogen temperature-programmed reduction, and X-ray photoelectron spectroscopy. The results indicate that calcination significantly affect the activity of the prepared catalysts. When calcined at a low temperature such as 400 degrees C, Ce, and Mn species form a solid solution of MnCeOx in the catalyst, thus locating the O atoms in a perturbed chemical surrounding in the catalysts. This increases the mobility of the O atoms during the reaction, probably contributing to the highest catalytic activity of CeOx-MnOx/TiO2 among all the tested catalysts. However, a further increase in the calcination temperature decreased the performance of the catalyst for the catalytic combustion of chlorobenzene. This is probably because of a reduction in surface chemisorbed oxygen concentration, a decrease in the interface area between metal oxides and MnCeOx caused by the isolation of MnOx or CeO2 from MnCeOx, and a decrease in the specific surface area of CeOx-MnOx/TiO2 catalyst due to the sintering of catalyst.