Nb-containing MCM-41 mesoporous molecular sieves were modified with ammoniu
m and copper cations and characterised by ESR, FTIR and H-2-TPR techniques.
The prepared materials were tested in the following catalytic reactions: N
O decomposition, reduction of NO with NH3, hydrosulphurisation of methanol,
and oxidation of thioethers with hydrogen peroxide. The oxidising characte
r of the NbMCM-41 mesoporous molecular sieves was revealed, which induces t
heir application as very active and selective catalysts in the oxidation of
thioethers with H2O2 to sulphoxides. HNbMCM-41 samples, which exhibit Lewi
s acidity after dehydroxylation, are selective catalysts in the methanethio
l synthesis in the reaction between methanol and hydrogen sulphide. Copper
modified NbMCM-41 sieves indicate the higher reducibility of cupric cations
than that observed when AlMCM-41 matrix for copper is used. The higher red
ucibility of cupric ions does not cause a higher activity in the catalytic
NO decomposition. (C) 2000 Elsevier Science B.V. All rights reserved.