Influence of lanthanum stoichiometry in La1−xFeO3−δ perovskites on their structure and catalytic performance in CH4 total oxidation

La/Sr-based perovskites as soot oxidation catalysts for Gasoline Particulate Filters

“…5b). Each peak presented a shake-up satellite located at a binding energy around 9.0 eV higher, which is characteristic of Fe 3+ species [44,45]. However, as shown by H 2 -TPR experiments, the presence of a small amount of Fe 4+ cannot be discarded.…”

Preparation and characterization of the non-stoichiometric La–Mn perovskites

“…Arai et al estimated the respective contribution of surface adsorbed oxygen species and surface lattice oxygen as catalytically active species for methane oxidation at reaction temperatures 450 Ce650 C, and argued that the contribution of surface lattice oxygen increased with reaction temperature increasing [8]. When charged oxygen species, including surface lattice oxygen and charged surface adsorbed oxygen, are catalytically active species, its consumption and regeneration is accompanied by cycling of valence state of neighboring transition metal ions such as B 3þ 4B 4þ and/or B 2þ 4B 3þ [1,3,6]. The ease at the cycling of valence state is dependent on kind of transition metal.…”

“…The ease at the cycling of valence state is dependent on kind of transition metal. Hence, kind of transition metal ions at the B-sites influences catalytic activity of perovskitetype oxides greatly [6,8].…”

“…When La 3þ ions were substituted partially by other metallic ions at a lower valence state such as Ca 2þ and Sr 2þ ions, lattice oxygen vacancy would be formed together with a part of transition metal ions changing into a higher valence state in the crystal structure to maintain electrical neutrality [1e5]. Oxygen in gas phase can adsorb at the surface lattice oxygen vacancy, forming adsorbed oxygen species either neutral or charged [1,3,6]. Perovskite-type oxides are thus effective for catalytic combustion of hydrocarbons and purification of exhaust gas of vehicles [1e8].…”

Spin conversion of hydrogen over LaFeO 3 /Al 2 O 3 catalysts at low temperature: Synthesis, characterization and activity

“…Perovskite type oxide catalysts having rare earth metals with transition metals are used at high temperature catalytic reactions, say, the dry reforming of methane for hydrogen production [24], methane total oxidation [25,26], toluene, propane, ethanol combustion [27e29], diesel soot removal [30,31], organic dye degradation [32,33], and interconnected anode materials for the solid oxide fuel cell [24]. Due to stability at high temperature, perovskite oxides have also been used as support material to synthesize the catalyst for CO methanation reaction [34].…”