Oxidation of NO over cobalt oxide supported on mesoporous silica

Cobalt oxide catalysts supported on mesoporous silica(Co3O4 /MPS) were prepared,characterized and applied for catalytic oxidation of NO. Effects of catalyst supports,calcination temperatures,H2O and SO2 on NO conversion were investigated. The samples were also characterized by BET,XRD,FTIR and TG/DTG. The results suggested that Co3O4 /MPS catalyst calcined at 573 K had the smallest crystal particles and the best surface dispersion. This catalyst had the highest activity and yielded 82% NO conversion at 573 K,at a space velocity of 12000 h 1 . Although the conversion of NO decreased with the introduction of H2O,it could be restored completely after removing residual H2O from Co3O4 /MPS catalyst by heating at 573 K. In the presence of SO2,the oxidation activity decreased and CoSO 4 was detected on the catalyst. The NO conversion decreased to 30.2% in the presence of SO2 and H2O. It could not be restored completely after cutting off H2O and SO2 . The deactivation of the catalyst in the presence of SO2 and H2O was attributed to the formation of cobalt sulfate species.