Selective catalytic reduction of NO with NH3 on mixed alumina–iron (III) oxide pillared montmorillonite “Cheto” Arizona, modified with hexamminecobalt (III) chloride

Abstract

Montmorillonite intercalated with mixed alumina–iron (III) oxide pillars and promoted with hexamminecobalt (III) chloride was studied in selective catalytic reduction of NO with NH3. Pillaring process extended the interlayer spacing by 0.236 nm and increased specific surface area (SSABET) from 33 m2 up to 299 m2. Interlayer space width did not change after calcination process, but high temperature could cause decomposition of hexamminecobalt (III) – [Co(NH3)6]3+, possibly to Co2+. Promotion of hexamminecobalt (III) chloride to pillared clay did not significantly change SSABET. The intercalation process influenced positively selective catalytic reduction activity, but very high formation of N2O was observed. Pillared clay, promoted with [Co(NH3)6]3+, showed higher selective catalytic reduction activity and much lower N2O formation than unpromoted, pillared sample. Clay with interlayer cations exchanged for [Co(NH3)6]3+, without pillaring, showed no selective catalytic reduction activity, but still produced high amounts of N2O.