【摘要】 以Ce(NO)3·6H2O、La(NO)3·6H2O和Zr(NO)4·3H2O为原料,NH3·H2O做pH指示剂,采用溶胶-凝胶法合成了La0.1Ce0.6Zr0.3O2纳米固溶体储氧材料;运用X射线衍射(XRD)、差热分析(DTA)、比表面积吸附(BET)和透射电镜(TEM)等方法考察了样品的物相结构、比表面积以及不同温度的煅烧对样品性能的影响.试验表明,以无机凝胶为前躯体,经500℃煅烧2h后形成了稳定的La0.1Ce0.6Zr0.3O2纳米固溶体储氧材料,其比表面积Sw=147.2m2/g,平均粒径d=12nm;在耐高温老化试验中,样品经1100℃煅烧2h后仍然保持单相,Sw=26.2m2/g,平均粒径d=36nm,显示出良好的耐高温老化性能.通过自制的汽车尾气净化催化剂及耐高温老化评价装置,考察了溶胶-凝胶法合成La0.1Ce0.6Zr0.3O2纳米固溶体储氧材料作为三元催化剂的催化净化效果;选用不同产地、不同组成的铈锆固溶体材料,在相同条件下附载贵金属(Pt、Pd)制备三元催化剂做汽车尾气催化剂.结果表明,La0.1Ce0.6Zr0.3O2纳米固溶体制备的三元催化剂的催化性能更好,具有较低的起燃温度和对NOx有更高的催化净化效率,即样品未老化前起燃温度为170℃,对NOx的净化效率达到了92.0%;样品经1050℃老化2h后,起燃温度为240℃,NOx的净化效率达到78.1%.更多还原

【Abstract】 The La0.1Ce0.6Zr0.3O2 oxygen-storage nanometer composite powder could be prepared with inorganic sol-gel method by using analytic reagent Ce(NO)3·6H2O\La(NO)3·6H2O\Zr(NO)4·3H2O as raw material &NH3·H2O as pH regulator. This composite powder was applied to automobile for exhaust catalysis &purification experiment. Its structure,surface area &the influence of calcinations temperature on its ability had been tested by means of X-ray diffraction(XRD),differential thermal analysis(DTA),surface absorption(BET) &transmitting electron microscopy(TEM). Results showed that by using inorganic gel as precursor &calcinated at 500 ℃for two hours,stabilized La0.1Ce0.6Zr0.3O2 oxygen-storage composite powder was formed. Its surface was 147.2 m2/g and its average particle size was 12 nm. However,after calcinations at 1 100 ℃for two hours,it still remained single phase. Its surface was 26.2 m2/g &its average particle size was 36 nm. That meant this powder had an excellent high temperature calcinations resistance ability. Made by sol-gel,this La0.1Ce0.6Zr0.3O2 oxygen-storage material’s three-way catalyst ability was tested by using self-made automobile exhaust catalysis &purification evaluation apparatus. In the experiment,Ce-Zr composite material of different composition &origin was selected to make three-way catalysts with precious metal (Pd/Pt). And these catalysts’ ability to catalyze &purify automobile exhaust was compared. Results showed that three-way catalysts made by La0.1Ce0.6Zr0.3O2 had much stronger NOx purification ability &lower T50. Before ageing,the three-way catalyst’s T50 was 170 ℃ &its purification efficiency was 92.0%,while after being aged in 1 050 ℃for two hours,its T50 got to 240 ℃whereas its purification efficiency got down to 78.0%.更多还原