Synthesize Of Mn,Cu Based Nano-Catalysts And Their Properties For NO Catalytic Reduction

In this paper, using mostly ZrOCl₂·8H₂O and Mn(NO₃)₂, Ce(NO₃)₂, nano- MnO_x/ZrO₂ and Cu/ZrO₂ catalysts held differ proportion were prepared by the way of Sol-Gel method and co-precipitation.method combined with vary drying technologies.The samples were characterized by BET, X-ray diffraction analysis, TEM, TG-DSC, etc. The on-lined gas-chromatogram with micro-reactor were introduced to examine the activities of catalytic reduction of these nano materials. The Autosorb-1-MP physical adsorptions instrument was used to measure the specific surface area and micro pore distribution of the samples. The Philips X'pert pho MPD type XRD was used to identify the crystal-phase. Using Zetzsch Sta 449C TG-DSC instrument analyzed the heat effect of the samples. On the above basis, we mainly studied the structure and catalytic performances of the nano non-noble metals samples and rather carefully studied the relationship between compose and catalytic reduction of nitrogen monoxide. The importance results were obtained as follows.1. It is concluded that we can gain the nano MnO_x/ZrO₂ with high specific surface area range from 100 to 300m²/g and micro pore and mespore structure, long with the increasing of metal(M) component, the amount of O—M—O bridge which is easy to rupture was also increase. Accordingly the specific surface area and pore volume of the samples were decreasing while the tap density was increasing. From the physical adsorption, knowing the type of micro pore in the samples belong to the tube shape capillary open at both ends, which will be great advantage to gas diffusion under catalytic reaction.2. Adding small amount of cerium into the MnO_x/ZrO₂ samples, the active component species state can be changed from high valent to low valent state, this will increase the superficial active site of the catalysts, and improve the activity properties of catalytic reduction of nitrogen. In the mean time, the activity component can be well dispersed on the nano MnO_x/ZrO₂ support by the adding of cerium.3. The sample has good anti-sintering ability and wide active temperature range. The results also suggested that manganese ions were the active sites, high activity to the reaction of NO reduction by CO. The results indicated that the size of catalytic particles concentrated on 20nm or so. The active species promotes the catalytic activity and NO conversion. The ratios of MnO_x/ZrO₂ was 1.5 has most high catalytic activity. The sample is so efficient with the NO conversion of 98% at 230℃. By adding small amount of cerium to MnO_x/ZrO₂ powders, which can improve the low temperature catalytic activity for NO more evidently.4. The catalytic activity of Mn0x/Zr02 is more higher than Cu/ ZrC>2 at the same conditions. The ratios of Cu/ 2'rO2\vas 1.5 has more higher catalytic activity. The sample is so efficient with the NO conversion of 85% at 250°C.