Evaluation of the catalytic oxidation of soot by CeO X -LaMnO 3 at different O 2 pressures synthesized by ultrasonic-assisted hydrothermal method

• Published in: Environmental science and pollution research international Vol. 27; no. 13; p. 15475
• Main Authors: Moreno-Román, Eddy Jonatan, Cruz-López, Arquímedes, García-Gómez, Celestino, Zanella, Rodolfo, Suárez-Vázquez, Santiago Iván
• Format: Journal Article
• Language: English
• Published: Germany 01-05-2020
• Subjects: Perovskite; Soot catalytic combustion; Redox properties; Solid solution; Bulk oxygen mobility; Ultrasonic-assisted hydrothermal
• ISSN: 1614-7499

In this work, the synthesis of catalyst with perovskite structure and chemical formula La
Ce
MnO
at x = 0 - 0.5 were successfully obtained by an ultrasonic-assisted hydrothermal method. Results show that the addition of Ce in La
Ce
MnO
have not substantial effect in textural and morphological properties; however, the formation of a new crystalline phase with final composition CeO
-La
Ce
MnO
was detected at values x > 0.3. All synthesized catalysts were tested in the soot oxidation under both, loose and tight contact in 20% O
/N
or 5% O
/N
atmospheres. CeO
-La
Ce
MnO
at x = 0.3 resulted in the best catalytic activity with activation energy values of 57.9 kJ
mol
. The interaction between Ce
and Mn
species in this catalyst can transfer electrons generating Mn
and Ce
. This reduction from Mn
to Mn
is accompanied by migration of vacancies to the surface promoting the adsorbed oxygen from the gas phase, need for balancing the chemical states. By increasing the temperature above 300 °C, the bulk oxygen migration to the surface is enhanced being the responsible for the oxygen availability. The formation of CeO
-La
Ce
MnO
promotes a stable redox cycle allowing the reusability of this catalyst even at low oxygen pressures after three different reaction cycles.