Pt/SiO2-Al2O3抗硫型柴油车尾气净化氧化催化剂的制备及性能  

Preparation and properties of the Pt /SiO_2-Al_2O_3 sulfur resistance diesel oxidation catalyst

作　　者：杨铮铮[1] 黎云祥[1] 廖运文[1] 李友平[1] 张纳[1] 

机构地区：[1]西华师范大学,环境科学与工程学院,南充637009

出　　处：《环境化学》2016年第8期1682-1689,共8页Environmental Chemistry

基　　金：西华师范大学博士启动基金(15E012)资助

摘　　要：使用浸渍法制备了一系列SiO2含量不同的改性Al2O3材料,并以此为载体制得一系列Pt/SiO_2-Al_2O_3柴油车尾气净化氧化催化剂(DOC).N2吸附-脱附实验和扫描电子显微镜(SEM)检测证实,SiO_2以多孔形式均匀覆盖在Al2O3表面,没有明显影响Al2O3的织构性质.运用热重法对各催化剂的抗硫性进行了表征,结果证实,SiO_2的引入有效提高了Pt/Al_2O_3催化剂的抗硫性;经硫累积实验后,所制备的Pt/SiO_2-Al_2O_3系列催化剂硫酸盐累积量均小于1.0 wt.%,而Pt/Al_2O_3的硫酸盐累积量约为3.94 wt.%.催化剂活性检测结果表明,适量SiO_2的引入不会影响Pt/Al_2O_3催化剂的活性;当SiO_2引入量为18 wt.%时,Pt/SiO_2(18%)-Al_2O_3催化剂不仅抗硫性能优异而且具有更好的耐久性,模拟柴油车使用160000 km后,其催化活性未明显降低.因此,本研究认为SiO_2在Pt/Al_2O_3DOC催化体系中,可以起着抑制硫中毒及提高耐久性的作用.A series of SiO2 modified Al2O3 mixed materials with different SiO2 content were prepared by using impregnation method, and then used as supports to prepare Pt/SiO2-Al2O3diesel oxidation catalysts （DOC）. N2 adsorption-desorption isotherm and scanning electron microscopy （SEM） results indicate that SiO2 was porous and covered on the surface of Al2O3 uniformly, which did not obviously affect the texture properties of Al2O3support. The thermo-gravimetrie analysis （TGA） was employed to characterize the sulfur resistance of as-prepared catalysts, which demonstrated that the introduction of SiO2 efficiently enhanced the sulfur resistance of Pt/Al2O3catalyst. After SO2 uptake experiment, the amount of cumulated sulfur over the Pt/SiO2-Al2O3 catalysts was less than 1.0 wt.%; while it was about 3.94 wt.% on the Pt/Al2O3 catalyst. The activity measurements suggest that the introduction of SiO2 did not obviously affect the activity of Pt/Al2O3 catalyst. When the SiO2 concentration was 18 wt.%, the Pt/SiO2 （18%）-Al2O3catalyst displayed outstanding sulfur resistance and durability. Moreover, the 160000 km vehicle aging simulation did not reduce the catalytic performance of Pt/Si02（18%）-Al2O3obviously. Thus, this study implies that SiO2 in the Pt/Al2O3 DOC catalyst can play important roles in inhibiting the sulfur poisoning and enhancing the durability.

关 键 词：大气污染控制 机动车尾气净化 负载型催化剂 硅溶胶 

分 类 号：X734.2[环境科学与工程—环境工程]