Cu-K型低温碳烟氧化催化剂的合成及表征

Oxidation Catalyst for Low Temperature Combustion of Diesel Soot

柴油机排放中碳烟的低温氧化是近年来研究的热点。通过原位合成法制备Cu2K/Al2O3和CuK2/Al2O3两种碳烟氧化催化剂,并采用低温氮吸附/脱附实验、X射线衍射、X射线光电子能谱、程序升温氧化对其结构进行系统表征,并用U碳模拟柴油机碳烟,研究其催化活性,评测其对柴油机排气中碳烟颗粒的净化效果。研究表明,Cu2K/Al2O3和CuK2/Al2O3两种催化剂均为中孔结构,孔径分布主要集中在2～5 nm。原位合成后,Cu、K以氧化态的形式均匀分布在Al2O3表面。添加Cu2K/Al2O3后,U碳的起始氧化温度(T)i和最高氧化峰温(Tp)分别为220℃、475℃,相比纯U碳,分别降低280℃和225℃;添加CuK2/Al2O3后,U碳的Ti和Tp分别为330℃、450℃,相比纯U碳,分别降低170℃和250℃。

Low temperature combustion of diesel soot is the focus of study in recent years.CuK2 /Al2O3 and Cu2K/Al2O3 catalysts for oxidation of diesel soot were prepared by an in situ synthesis method.Structures and catalytic activities were examined by low temperature nitrogen adsorption/adsorption experiments,X-ray diffraction,X-ray photo electron spectroscopy,and temperature-programmed oxidation.Results indicated that the pore structures of CuK2 /Al2O3 and Cu2K/Al2O3 were mesopore,with pore sizes in the range of 2~5 nm.Cu and K elements in oxidized states were distributed uniformly on the surface of Al2O3.Ignition oxidation temperature（Ti） and peak of oxidation temperature（Tp） of pure U-carbon after adding Cu2K/Al2O3 were 220 ℃ and 475 ℃ respectively,about 280 ℃ and 225 ℃ lower than those of U-carbon only.With addition of CuK2/Al2O3,U-carbon Ti and Tp were 330 ℃ and 450 ℃ respectively,about 170 ℃ and 250 ℃ lower than those of pure U-carbon.