| dc.description.abstract | Abstract
In our previous studies, doping MnOx into CeO2 increase the mobility of lattice oxygen and enhanced the activity of the activity of the 7%CuO/Ce1-xMnxO2 catalyst in the selective oxidation of CO in the H2-rich feed. In order to promote of mechanical strength and the stability of support, moreover to Alumina was incorporated with the solid solution of Ce1-xMnxO2 to form Ce1-xMnxO2-Al2O3 mixed oxides, by the suspension /co-precipitation method, to be used as supports ofCuO/Ce1-xMnxO2-Al2O3 catalyst. They were characterized and effects of Al2O3 on the selective oxidation of CO in excess hydrogen were examined. Characterization of catalysts were performed by XRD, TPR, XPS, Auger. All catalysts were reduced to room temperature in helium and then the feed H2/CO/O2/He(50/1/1/48) mixed was diverted to the reactor at a flow rate of 30ml/ min (F/W = 10,000ml/g h).
For Ce1-xMnxO2 with x = 0.1~0.3, incorporating an appropriate amount of Mn4+ into the CeO2 lattice to form a solid solution facilitated the release of the bulk lattice oxygen. Some MnOx might aggregate and be split out from the solid solution of Ce1-xMnxO2 as the fraction of Mn incorporated excess 0.3, and then Mn3+ into the CeO2.
7%CuO/Ce0.9Mn0.1O2 catalyst was the most active one, it was more active than the 7%CuO/CeO2 catalyst, with a T100 temperature (90-95°C) for complete conversion that was above 5°C less than that of 7%CuO/CeO2 (95-100°C) and the selective oxidation of CO was still 100%. The promotion of CO oxidation became weaker as the fraction of Mn incorporated increase above 0.5.
For doping appropriate small friction as the amount of Mn about o.1 into the Ce1-xMnxO2 for 7%CuO/Ce0.9Mn0.1O2-x%Al2O3 catalysts. This interfacial perimeter also decreased as the amount of Al2O3 incorporated into Ce0.9Mn0.1O2-x%Al2O3 increased above 30%, so that CO oxidation became weaker.
Because a gas stream from reformer always contains CO2 and H2O, so that a catalyst of selective oxidation of CO must be resistant to both CO2 and H2O. The 7%CuO/Ce1-xMnxO2-20%Al2O3 catalyst rose by about 35°C from 95-100°C to 130-135°C when an H2-rich feed in presence of 15%CO2. The 7%CuO/Ce1-xMnxO2-20%Al2O3 created the catalyst bed to stop up and reaction can not finish, so that the catalyst had the hygroscopicity. A long (200 h) run over the 7%CuO/Ce0.9Mn0.1O2-20%Al2O3 catalyst was conducted at 100°C, with about 93% conversion; the performance was stable when the feed no CO2 and H2O. | en_US |