Sol–gel synthesis of manganese-doped ceria from acetylacetonate precursors

Abstract

Pure and manganese-doped ceria nanopowders were prepared by the sol–gel method using cerium acetylacetonate hydrate and manganese acetylacetonate as precursors, while methanol and ethylene glycol were used as a double solvent. The prepared materials have been characterized by X-ray diffraction, Fourier transformed infrared spectroscopy, differential thermal and thermogravimetric analysis, scanning electron microscope, atomic force microscope, and N₂ adsorption/desorption isotherms. In the course of synthesis and aging, hydrolysis of the precursors and gel formation were achieved. The process was more advanced in the doped samples. Grain growth kinetics pointed out that manganese inhibits the grain growth rate of ceria. On the basis of thermal evolution characterization 500 °C and 2 h were selected as thermal treatment parameters. Pure ceria was the only crystal phase obtained, while the decrease of lattice constant a revealed the entrance of Mn in the crystal lattice of ceria. Doped samples displayed smaller crystallite sizes and greater specific surface areas in comparison with pure sample. The catalytic efficiency of the prepared samples was tested for toluene oxidation and it was established that doping with manganese improves the catalytic efficiency of ceria.

Highlights

Manganese doped ceria nanopowders were prepared from acetylacetonate precursors.

Double solvents (methanol and ethylene glycol) have to be used.

Manganese inhibits the grain growth rate of ceria.

Doped samples exhibit smaller crystallite sizes and greater specific surface areas.

Doping with manganese improves the catalytic efficiency of ceria for toluene oxidation.