Calcium and strontium substituted lanthanum manganite–cobaltite [La1−(Ca,Sr) Mn0.5Co0.5O3] nano-catalysts for low temperature CO oxidation

Structural and redox features of La0.7Bi0.3Mn1−xCoxO3 nanoperovskites for ethane combustion and CO oxidation

“…The effect of Co substitution on the catalytic activity might be related to the electronic configuration which intervenes directly in the structural changes formed. The electronic configuration causes two different mechanisms, namely, intrafacial and suprafacial processes for C 2 H 6 combustion and CO oxidation, respectively, as reported in other works . In suprafacial mechanism, adsorbed oxygen and oxygen vacancies are the dominant species participating in CO oxidation.…”

“…The presence of Mn 4+ and Co 2+ ions has been also observed in LaMn 1− x Co x O 3 for x up to 0.50 that can help to overall oxidation activity of these samples . Our previous work showed that the catalytic oxidation of LaMn 0.5 Co 0.5 O 3 with increase in Sr substitution for La shifts to lower temperature, whereas with Ca substitution shifts to higher temperature.…”

La1−xCaxCo1−yMgyO3 nano‐perovskites as CO oxidation catalysts: Structural and catalytic properties

“…Again this result is in accordance to decrease in unit cell volume obtained from XRD analysis. Consequently, the orthorhombic structure for C0M50 changes to rhombohedral for C60M50, in which the bending of the (metal‐to‐oxygen bond) B–O–B bond decreases . However, the decrease in 〈 r B–O 〉 is dominated for x up to 0.60 and factor t increases.…”

“…When Ca 2+ substitutes for La 3+ ions in LaMg 0.5 Co 0.5 O 3 , 〈 r A–O 〉 must decrease and we expect factor t decreases. But, the introduction of alkaline‐earth cations instead of La 3+ cations in LaMg 0.5 Co 0.5 O 3 increases the average degree of oxidation of Co . Again, some oxidized Co 3+ ions convert into Co 4+ ions with a lower ionic radius, so 〈 r B–O 〉 decreases.…”

“…Most researchers believe that the catalytic activity for the complete oxidation of CO is mainly determined by the transition metals . It has also been reported that partial substitution of transition metal at B site with other trivalent cation can be effective to enhance oxidation activity of perovskites .…”