Nanocrystalline La_1–xK_xFeO₃ (x = 0–0.4) Oxides for Catalytic Removal of Soot from Practical Diesel Exhaust Emission

Abstract

The nanocrystalline, porous, perovskite La1–x K x FeO3 (x = 0–0.4) powders and La0.8K0.2FeO3-coated honeycomb ceramic device were prepared by the citrate-gel process and the citrate-gel assisted dip-coating method at a low calcination temperature of 600̊C for 6 h, respectively. All the perovskite powders can effectively catalyze the soot combustion and among them the La0.8K0.2FeO3 catalyst exhibits the highest catalytic activity for the soot combustion, with a lowest T50 (350 °C) owing to a high specific surface area and large pore sizes. This optimized La0.8K0.2FeO3 catalyst is proved by the bench test for the practical exhaust gas emission and the La0.8K0.2FeO3-coated honeycomb ceramic device has a effective capture of particulate matter from the exhaust emission at a low temperature and starts to efficiently catalyze oxidization reactions of the particulate matter at the temperature around 245 °C (T 20), leads the smoke opacity near zero at the operational temperature of 400 °C.

Catalytic combustion of soot over Ce and Co substituted three-dimensionally ordered macroporous La1−xCexFe1−yCoyO3 perovskite catalysts

“…The absorption bands at 600 cm À1 are attributed to the Fe-O or Co-O stretching vibrations and the peaks around 400 cm À1 correspond to the O-Fe-O or O-Co-O deformation vibrations in the perovskites. 23,28,33 The FT-IR results further demonstrate that the ABO 3 perovskite structures are present and stable aer substitution. When the content of Ce at A-site increases to 0.2, a new band phase at about 660 cm À1 related to the Co 3 O 4 impurity is witnessed.…”

Perovskites as Substitutes of Noble Metals for Heterogeneous Catalysis: Dream or Reality

“…503 Partial substitution of La by K allowed remarkable improvement of the activity of LaFeO 3 for soot combustion. 506,507 Substituting La for Sr is also a good way to improve both activity and stability, but Sr doping seems to be less efficient than K for soot combustion. 508 Nevertheless, optimal performance was obtained over La 0.2 Sr 0.8 FeO 3 and then at a high Sr substitution degree.…”

Catalytic Activity of Nanocrystalline Porous La<SUB>0.8</SUB>K<SUB>0.2</SUB>Fe<SUB>1−<I>x</I></SUB>Mn<SUB><I>x</I></SUB>O<SUB>3</SUB> for Simultaneous Removal of Soot and Nitrogen Oxides

“…34 The reagents used were analytic grade of La(NO 3 3 · 6H 2 O, Fe(NO 3 3 · 9H 2 O, K 2 CO 3 , C 4 H 6 MnO 4 · 4H 2 O and citric acid (CA). The molar ratio of citric acid to the total metal ions was 1:1.1.…”