Reaction kinetics and mechanism of CH4-SCR on Ru-In/H-SSZ-13

摘要

The reaction kinetics and mechanism of CH4-SCR on Ru-In/H-SSZ-13 as a model multifunctional catalyst, together with Ru/H-SSZ-13 and In/H-SSZ-13 for reference, were investigated. In the low-temperature region (260 degrees C). With increasing reaction temperatures from 250 to 500 degrees C, the reaction orders of NO in CH4-SCR on Ru-In/H-SSZ-13 gradually decreased from 1.80 to 0.43 while the reaction orders of CH(4)gradually increased from 0.33 to 0.86 instead. The surface species formed on the catalyst samples and their evolutions at 250 and 400 degrees C were monitored byin situDRIFT spectroscopy. The organonitrogen compounds,i.e.methyl nitrite and its isomer nitromethane, were identified as the key intermediates in CH4-SCR, and their existence was further confirmed by temperature-programmed surface reaction and pulse-response experiments. According to the above-mentioned results, the temperature-dependent CH4-SCR mechanism on Ru-In/H-SSZ-13 was finally established.