摘要
采用表面活性剂改性的沉淀法合成了系列掺杂钇、镧、钡的氧化锆铝复合氧化物。通过XRD、XRF、低温N2吸附和CO脉冲化学吸附等手段考察了表面活性剂、助剂、焙烧温度对复合材料结构、孔结构以及负载0.5%铑催化剂的分散性能等的影响。研究表明:与采用常规沉淀法合成的氧化锆铝复合氧化物相比,添加表面活性剂合成的样品具有更大的比表面积、孔容和适合的孔径分布。分别或同时掺杂La、Ba、Y合成的氧化锆铝复合氧化物都能抑制氧化铝的α相变,提高复合材料和催化剂表面金属Rh的高温抗烧结能力,特别是同时掺杂La、Ba、Y合成的Rh/LBYZA样品经1100℃4h焙烧后仍有17.82%的金属分散度。以LBYZA为载体制备的新鲜催化剂(600℃4h焙烧样品)在CO选择还原NO反应中NO和CO的起燃温度分别为240、243℃,完全燃烧温度分别为273、280℃,表现出较高的催化活性。
A series of ZrO2-Al2O3 mixed oxides with La, Ba and Y were prepared by co-precipitation method which modified by surfactant. The samples were characterized by XRD, XRF, BET measurements and CO pulse ehemiadsorption. The effect of surfactant, promoter and calcination temperature on structure, pore structure of these materials and dispersion of Rh on composite supports was investigated. It was found that compared with materials prepared by conventional co-precipitation method, the samples prepared by new method had larger specific surface area and pore volume, appropriate pore size distribution. No matter how adding La, Ba and Y separately or together, phase change of T-Al2O3 to ot-Al2O3 of the samples was inhibited and thermal stability of the composite supports and Rh was improved at high temperature. In particular, high dispersion of precious metals （D% =17.82%） of the catalyst Rh/LBYZA which adding La, Ba and Y together was achieved after calcination at 1 100 ℃ for 4 h. The catalyst supported on LBYZA after calcination at 600 ℃ for 4 h had higher catalytic activity for NO selective reduced by CO. Light-off temperature （T50%NO=240, T50%CO=243） and Combustion temperature （T90%NO=273, T90%CO=280） of NO and CO were lower than the catalysts supported on T-Al2O3 and other ZrOz-Al2O3 materials.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2010年第1期61-66,共6页
Chinese Journal of Inorganic Chemistry
基金
国家科技部支撑计划(No.2007BAE08B01)项目资助
