Insight into high-performance of La-Ce-MnOx oxides with different calcination temperatures for diesel soot combustion

A series of La-Ce-MnOx catalysts derived from the precipitation of acetate salt and ammonium carbonate were calcined at different temperatures and applied for the catalytic oxidation of soot from diesel exhausts. The structure states of the as-prepared catalysts and catalytic behaviour for soot oxidation were studied by many characterization techniques such as XRD, XANES, N-2 adsorption-desorption, TPR, O-2-TPD, XPS and TGA. XANES results display most Mn species are Mn4+ when the samples are calcined at 500 and 600 degrees C. However, for MCLa-700 and MCLa-800 catalysts, the predominance valence is 3+ ions. The MCLa-500 and MCLa-600 catalysts possess higher concentrations of surface active oxygen evidenced by H-2-TPR and soot-TPR. Therefore, the combustion rate of soot over MCLa-600 catalyst is remarkably increased with the T-10, T-50 and T-90 at 318 degrees C, 360 degrees C and 388 degrees C under NOx atmosphere respectively.