کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
48984 | 46536 | 2007 | 7 صفحه PDF | دانلود رایگان |
A Co-H-MFI sample has been studied through FT-IR spectroscopy of in situ adsorption and co-adsorption of probe molecules (o-toluonitrile, CO, NO) and has been tested in the CH4-SCR process under IR operando conditions. The o-toluonitrile (oTN) adsorption and the oTN and NO co-adsorption, show that both Co2+ and Co3+ species are present on the catalyst surface. Co3+ species are located inside the zeolitic channels while Co2+ ions are distributed both at the external and at the internal surfaces. The operando study show the activity of Co3+ species in the reaction. The existence of three parallel reactions, CH4-SCR, CH4 total oxidation and NO to NO2 oxidation, has been confirmed. Isocyanate species and nitrate-like species appear to be intermediates of CH4-SCR and NO oxidation, respectively. A mechanism for CH4-SCR has been proposed. Co2+ substitutional sites, very evident and predominant in the catalyst, which are very hardly reducible, seem not to play a key role in the SCR process.
Journal: Applied Catalysis B: Environmental - Volume 71, Issues 3–4, 15 February 2007, Pages 216–222