A series of copper-cobalt oxides supported on nano-titanium dioxide were prepared for the reduction of nitric oxide with carbon monoxide and characterized using techniques such as XRD,BET and TPR.Catalyst CuCoOx/TiO2 with Cu/Co molar ratio of 1/2,CuCo total loading of 30%at the calcination temperature of 350°C formed CuCo2O4 spinel and had the highest activity.NO conversion reached 98.9%at 200°C.Mechanism of the reduction was also investigated,N2O was mainly yielded below 100°C,while N2 was produced instead at higher temperature.O2 was supposed to accelerate the reaction between NOx and CO for its oxidation of NO to give more easily reduced NO2,but the oxidation of CO by O2 to CO2 decreased the speed of the reaction greatly.Either SO2 or H2O had no adverse impact on the activity of NO reduction;however,in the presence of both SO2 and H2O,the catalyst deactivated quickly.
CHEN Xia,ZHANG Junfeng,HUANG Yan,TONG Zhiquan,HUANG Ming Department of Environmental Engineering,Xiangtan University,Xiangtan 411105,China
The selective catalytic oxidation (SCO) of NO was studied on a catalyst consisting of iron-manganese oxide supported on mesoporous silica (MPS) with different Mn/Fe ratios. Effects of the amount of manganese and iron, oxygen, and calcination temperature on NO conversion were also investigated. It was found that the Mn-Fe/MPS catalyst with a Mn/Fe molar ratio of 1 showed the highest activity at the calcination temperature of 400 °C. The results showed that over this catalyst, NO conversion reached 70% under the condition of 280 °C and a space velocity of 5000 h-1. SO2 and H2O had no adverse impact on the reaction activity when the SCO reaction temperature was above 240 °C. In addition, the SCO activity was suppressed gradually in the presence of SO2 and H2O below 240 °C, and such an effect was reversible after heating treatment.
