Dispersion of BaCO3 on the surface of gamma-Al2O3 and its storage capacity for NOx

用浸渍法制备了BaCO3-Pt/-γAl2O3和Pt-BaCO3/-γAl2O3两种样品.X射线衍射和显微红外等表征结果表明,BaCO3可以在载体表面实现单层分散;Pt和BaCO3的负载顺序不同,则BaCO3的分散容量不同.以1%Pt/-γAl2O3为载体制备的BaCO3-Pt/-γAl2O3样品中BaCO3的分散阈值为0.24 g/g.氮氧化物存储量测试结果表明,BaCO3负载量在分散阈值时,NOx的吸附穿透时间和钡离子的有效利用率均达到最大值,表现出阈值效应.而在BaCO3/-γAl2O3上负载Pt制备的1%Pt-BaCO3/-γAl2O3样品中,BaCO3的分散容量降低,氮氧化物存储量也...BaCO3-Pt/-gamma-Al2O3 and Pt-BaCO3/-Al2O3 samples with different BaCO3 loadings were prepared by the impregnation method and investigated as NO, storage catalysts. XRD and FTAR spectroscopy were used to characterize the samples. BaCO3 could disperse onto the surface of the support, and the dispersed BaCO3 was the major active species for NO, storage. The sample with the utmost dispersion capacity (threshold) of BaCO3 had the largest NO, storage capacity and the largest percentage of Ba involved in the storage. Different loading sequences of Pt and BaCO3 resulted in different BaCO3 dispersion thresholds. When loading Pt before BaCO3, the dispersion threshold of BaCO3 was 0.24 g/g. However, when impregnating BaCO3/gamma-Al2O3 with H2PtCl6 solution, the dispersion capacity of BaCO3 decreased. By fixing the BaCO3 content at the dispersion threshold and loading Pt before BaCO3, we obtained a catalyst with high NO, storage capacity and large percentage of active Ba.SCI(E)中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)2121088-10922