| Abstract |
The objective of this work is the study of fundamental common aspects of NO, catalytic reduction over a Co/Pd-HFER zeolite catalyst, using methanol or methane as reducing agent. Temperature Programmed Surface Reaction (TPSR) studies were performed with reactant mixtures comprising NO(2) and one of the reducing agents. The formation of formaldehyde was detected in both studied reactions (NO(2)-CH(4) and NO(2)-CH(3)OH) in the temperature range between 100 and 220 degrees C. At higher temperature. when the NO(x) reduction process effectively begins, formaldehyde starts to be consumed. Using methanol as reducing agent, nitromethane and nitrosomethane, are detected. At 300 degrees C these species are consumed and cyanides and iso-cyanides formation occurs. On the contrary, with methane, these last species were not detected; however, there are strong evidences for CH(3)NO and CH(3)NO(2) formation. Thus, using methanol or methane, similar phenomena were detected. In both cases, common intermediary species seem to play an important role in the NO(x) reduction process to N(2). These results suggest that methanol can be considered as a reaction intermediate species in the mechanism of the reduction of NO(2) with methane, over cobalt/palladium-based ferrierite catalysts. (C) 2007 Elsevier B.V. All rights reserved. |
