γ-Al2O3对介孔稀土复合氧化物催化特性的影响研究

利用γ-Al2O3替代了60%的Ce/Zr固溶基体,对介孔La/Ce/Zr复合氧化物进行改性.利用ICP分析仪、X射线衍射仪、SEM、比表面仪、激光粒度仪、热重分析仪等表征技术对制备得到的催化剂粉体进行表征.结果显示,活性Al2O3显著提高了催化剂粉体的比表面积,改善了高温下的表面烧结程度,增强了催化剂的热稳定性能并提高了其使用寿命,同时也增加了催化剂粉体的储氧能力和对NO的吸附能力,从而提高了催化活性,明显降低了PM的起燃温度和最高活性工作温度,提高了其对NOx的最大还原率.该研究结果对同时去除船舶柴油机排气污染物PM和NOx具有非常重要的工程应用价值.

Research on the effect of γ-Al2O3 for the catalytic properties of mesoporous rare-earth composite oxides

A mesoporous La/Ce/Zr composite oxide catalyst was prepared, in whichγ-Al2O3worked as the mainmodi-fication component to replace 60wt% of Ce/Zr solid solution matrix. The structures and performances of the compositeox-ide catalyst powder were characterized by ICP analyzer, X-ray Diffraction(XRD), scanning electron microscope(SEM),spe-cific surface analyzer, laser particle size analyzer, thermal gravimetric analyzer(TGA) and other characterization techniques. The results showed that active Al2O3modification significantly increased the catalyst powder specific surface areas andim-proved the sintering degree of the surface under high service temperature, which enhanced the thermal stability of thecata-lyst and increased its service life. Meanwhile, the oxygen storage capacity and the adsorption capacity to NO are increased also. These characteristics by the Al2O3 modification helped improving the catalytic activity to the reduction of NOx andsig-nificantly reducing the ignition temperature and the highest active temperature to PM. The results of this study have anim-portant engineering application value for the simultaneous removal of marine diesel engine exhaust pollutants of PM and NOx.