Density functional calculation on the adsorption of nitrogen oxides and water on ion exchanged ZSM-5

Removal of nitrogen oxides NO.from exhaust gases in the presence of excess oxygen is a major problem. Our work is x aimed in a direction to propose effective catalyst for NO removal. Configuration and electronic states of adsorbed NO x x species on various ion exchanged ZSM-5 have been investigated by quantum chemical calculation based on Density Functional Theory DFT.. In case of NO adsorption on monovalent and divalent metal cations, nitrogen atom of NO molecule interacts with exchanged metal cations. Whereas in case of the trivalent metal cations extraframework oxygen is also involved along with the exchanged cations in adsorption process. NO2 and H2O adsorption over exchanged metal cation were also studied. Different combination of exchangeable metal cations over NO adsorption was studied. Large x affinity of NO was observed, when Cuq, Fe–OH.q, Co–OH.q, In–O.q, Tl–O.q are present in ZSM-5 as exchanged x cations. q1998 Elsevier Science B.V. All rights reserved.