FT-IR studies of the NO adsorption on rare earth (Eu/Gd/Tb) exchanged new generation silicoaluminophosphate catalysts of chabazite type

Novel rare earth exchanged silicoaluminophosphate catalysts (small pore, 0. 43 nm) of chabazite type have been prepared. The rare earth elements europi um (Eu), gadolinium (Gd) and terbium (Tb) were used for preparing the catio n exchanged chabazite type SAPO-18 catalysts. Routine and sophisticated ins trumental techniques were used for the material characterisation, The FT-IR technique was used to study the in situ interaction of NO on the rare eart h exchanged SAPO-18 catalysts. The adsorption of NO on the Eu-, Gd-, Tb-exc hanged SAPO-18 samples led to the formation of nitrous oxide, mono- and din itrosyl complexes of Eu, Gd and Tb, nitrogen dioxide and nitrate species. ( C) 2000 Elsevier Science B.V. All rights reserved.