Selective oxidation of CO in rich hydrogen stream over Ag/OMS-2 catalyst

The Ag/OMS-2 catalysts prepared by the simple reflux method show high activity and stability for the CO selective oxidation in rich H-2 stream. The catalysts are characterized by means of XRD, BET, XRF, XPS, SEM, TEM and H-2-TPR. The results show that the materials have the cryptomelane type structure with a one-dimensional channel and Ag ions are well dispersed in the micropores of the cryptomelane structure. The catalytic activity for CO selective oxidation was increased after Ag introduction. In the longtime stability test under the realistic reaction condition, 100% CO conversion can maintain for 250 h at 120 degrees C with about 90% selectivity. The main reason for the deactivation of the Ag/OMS-2 catalysts is that the fine-dispersed silver species are agglomerated to form Ag2O and parts of OMS-2 are reduced to Mn2O3, accompanied with a structure reordering. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.