Selective catalytic reduction of NOx with NH3 over iron-cerium mixed oxide catalyst: catalytic performance and characterization

BACKGROUND Selective catalytic reduction (SCR) of NO with NH3 has been proved to reduce nitric oxides in exhaust flue gas from coal-fired power plants. The commercial V2O5 -WO3 (MoO3)/TiO2 catalyst has the disadvantages of high reaction temperature (573-673 K), high conversion of SO2 to SO3 and toxicity of vanadium pent-oxide to the environment and human health. Therefore, it is of some urgency to develop SCR catalyst, which works effectively in medium and low temperature ranges. In this study, a series of cerium-iron mixed oxide catalyst were prepared through a co-precipitation method and showed strong low-temperature SCR activity. RESULTS The SCR activity over iron oxide was improved significantly by adding a small amount of cerium, especially the low-temperature activity. Cerium sharply increased the BET surface area and the pore volume of iron oxide, and also enhanced its oxidation activity of NO to NO2. The NOx conversion was improved when partial NO2 was introduced into the flue gas. Iron oxide in catalyst was amorphous phase after adding a small amount of cerium. CONCLUSION The SCR activity over iron oxide was improved by substituting partial Fe with Ce, and the optimized conditions for SCR with iron-cerium mixed oxide catalyst were validated in this study.(c) 2012 Society of Chemical Industry