Influence of Sr Substitution on Catalytic Performance of LaMnO_3/Ni Metal foam Composite for CO Oxidation

10.4209/aaqr.2014.11.0286

Po-Yang Peng；Yi-Chiun Tsai；Jen-Taut Yeh；Yung-Sen Lin；Chao-Ming Huang

LSMO ； Nickel metal foam ； Catalytic oxidation ； Carbon monoxide

Aerosol and Air Quality Research

15卷4期（2015 / 08 / 01）

1662 - 1671

英文

A series of Sr-substituted lanthanum manganite perovskites, La_(1-x)Sr_xMnO_3 (LSMO, x=0, 0.1, 0.2, and 0.3), with mesoporous structures were prepared and coated onto a three-dimensional Ni metal foam (MF) as composite catalysts. The catalytic performances of La_(0.8)Sr_(0.2)MnO_3/MF and La_(0.7)Sr_(0.3)MnO_3/MF were found to be superior to those of La_(0.9)Sr_(0.1)MnO_3/MF, LaMnO_3/MF, and LaMnO_3 powder in terms of catalytic oxidation of carbon monoxide with air. Under the reaction conditions (1.5 vol.% CO and air balance at a weight hourly space velocity of 90,000 hr^(-1)), La_(0.8)Sr_(0.2)MnO_3/MF reached 100% catalytic oxidation of CO, which is 27% higher than that of LaMnO_3 powder. Sr substitution induced an increase of Mn^(4+) and adsorbed surface oxygen species (O^-, O_2^-, or O_2^(2-)), which increased the number of active centers for oxidation and thus enhanced the oxidizing ability of the catalyst. The high activity and excellent stability of La_(0.8)Sr_(0.2)MnO_3/MF catalyst can be ascribed to a synergistic effect between the mesoporous structure and the high number of adsorbed oxygen species of the catalyst as well as the interconnected three-dimensional reticular configuration of the nickel metal support, which increases the number of active sites and enhances mass transfer for CO and O_2. La_(0.8)Sr_(0.2)MnO_3/MF composite can potentially be used in catalytic converters for CO removal of automotive exhaust gases.