Selective reduction of nitric oxide with methane on gallium and indium containing H-ZSM-5 catalysts: Formation of active sites by solid-state ion exchange
- Waseda Univ., Tokyo (Japan)
H-ZSM-5 catalysts containing Ga and In were prepared by the ion-exchange method and by physically mixing H-ZSM-5 and Ca{sub 2}O{sub 3} or In{sub 2}O{sub 3}, and they were used in the NO reduction with methane to determine the active species of these metals, particularly of In, for this reaction. Ga-loaded H-ZSM-5 prepared by the ion-exchange method gave a higher catalytic activity than the physical mixture of Ga{sub 2}O{sub 3} and H-ZSM-5, of which the catalytic activity was comparable to that of H-ZSM-5. On the contrary, both ion-exchange and physical mixing methods yielded equally high catalytic activities of In-loaded H-ZSM-5. The reduction of No on these catalysts proceeds consecutively by way of oxidation of NO to NO{sub 2} and reduction of NO{sub 2} with CH{sub 4} to N{sub 2}. With increasing heat treatment temperature, the catalytic activity of the mixture of In{sub 2}O{sub 3} and H-ZSM-5 for the reduction of NO{sub 2} increased, while that for NO oxidation decreased. An IR study of OH groups on this catalyst indicated that the solid-state exchange reaction occurred between In{sub 2}O{sub 3} and H-ZSM-5 leading to the increase in the number of indium cation sites and consequently the catalytic activity for NO{sub 2} reduction. 21 refs., 8 figs., 1 tab.
- OSTI ID:
- 471641
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 161; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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