Synergic effect of Cu/Ce0.5Pr0.5O2-δ and Ce0.5Pr0.5O2-δ in soot combustion

Abstract

Please cite this article in press as: V. Rico-Pérez, et al., Synergic effect of Cu/Ce 0.5 Pr 0.5 O 2-␦ and Ce 0.5 Pr 0.5 O 2-␦ in soot combustion, Appl. Catal. B: Environ. (2016), http://dx. a b s t r a c tA series of 5%Cu/Ce 0.5 Pr 0.5 O 2-␦ and Ce 0.5 Pr 0.5 O 2-␦ mixed oxides have been prepared and combined in different ratios. The resulting catalysts have been characterized by N 2 adsorption, XRD, Raman spectroscopy and H 2 -TPR and tested for soot combustion by means of temperature-programmed experiments. The optimum catalyst for soot combustion in NO x /O 2 /N 2 atmosphere is the mixture containing 40% Cu/Ce 0.5 Pr 0.5 O 2-␦ and 60% Ce 0.5 Pr 0.5 O 2-␦ . This mixture is more active than a reference catalyst containing the same amount of copper distributed in the whole Ce-Pr mixed oxide support. The benefit of mixing Ce 0.5 Pr 0.5 O 2-␦ particles with and without copper in a single catalyst formulation is that the participation of the two soot combustion mechanisms based on active oxygen and NO 2 , respectively, is optimized. The particles with copper mainly promote the catalytic oxidation of NO to NO 2 (the NO x -assisted mechanism) while those without copper are more effective in promoting the active oxygen mechanism. If copper is loaded homogeneously in all the Ce 0.5 Pr 0.5 O 2-␦ particles, the positive effect of copper improving NO 2 production is offset by the lower efficiency of the active oxygen mechanism, due to a lack of active oxygen on the Ce 0.5 Pr 0.5 O 2-␦ support.

Design structure for CePr mixed oxide catalysts in soot combustion

“…4 corresponds to the presence of oxygen vacancies. 34,56 Comparison of the Raman line shape in the four CePr mixed oxides shows that the incorporation of Pr ions into CeO 2 must be accompanied by the generation of oxygen vacancies. The population of oxygen vacancies is proportional to the peak area ratio of about 570 to 450 cm À1 .…”

“…34,35 Among them, the solid-phase grinding method is the easiest technique to control the positions of the metal atoms in the structure. Moreover, this method is effective for building catalysts with different structures.…”

Enhanced Catalytic Performance of Manganese and Cobalt Co–doped CeO2 Catalysts for Diesel Soot Oxidation

“…Powder XRD patterns of C773, CM773, CC773, and CMC773 catalysts are shown in Figure . All catalysts show (111), (200), (220), (311), (420), and (422) diffraction lines, which can be attributed to cubic fluorite structured CeO 2 with a space group Fm3m . Furthermore, no diffraction peaks pertaining to cobalt oxides (CoO and Co 3 O 4 ) and manganese oxides (Mn 2 O 3 and Mn 3 O 4 ) were observed in CM773 and CC773 from Figure .…”

Low‐Cost Catalysts for the Water Gas Shift Reaction Based on Cu–Ni on La‐Promoted Ceria

“…The redox and catalytic properties of the support can be enhanced by adding another element to the lattice as a promoter. La‐ and Pr‐containing ceria supports have shown higher performance than pure ceria . Previously, we studied the addition of Pr to ceria‐supported Cu–Ni catalysts, observed a promoting effect of Ce 4+ /Ce 3+ and Pr 4+ /Pr 3+ redox couples on the WGS reaction, and concluded that the presence of Pr in small amounts (ca.…”