摘要
本文采用XRD,NH_3-TPD,IR以及TEM等方法考察了Pt/BaKL沸石中Ba^(2+)的作用。NH_3-TPD结果表明,交换Ba^(2+)后的L型沸石的酸性,由于阳离子的作用仅在弱酸范围内有些改变,但与载铂的沸石的催化活性无明显的对应关系。IR及XRD谱线表明,BaKL沸石中Ba^(2+)在最佳交换度(26.3%)时,随预培烧温度的提高,使Ba^(2+)处于沸石孔道中B、C、D位置,接近于最佳分布,此时IR谱线上1421cm^(-1)处有一新峰。当沸石负载铂后,因铂与Ba^(2+)的相互作用,新峰消失,导致铂粒在沸石上分布更加均匀;铂粒在1.5—3.0nm之间占有最大比例,使得Pt/BaKL沸石呈现芳构化活性及选择性高于Pt/KL沸石,分别为～98%和～95%。
In this paper, the function of Ba^(2+) in Pt/BaKL zeolite has been investigated by XRD NH_3-TPD and TEM methods. Ammonia-TPD results showed that the number of weak acidic sites in L zeolite was changed through Ba^(2+) action, but no relation exists between acidity and catalytic activity. IR and XRD spectra showed that Ba^(2+) is optimally distributed in B, C, D locations of the channels of the zeolite, when Ba^(2+) is preseat in the optimal amount of 26.3% and the pretreatment temperature is raised. Undcr this condition IR spectra showed that a new peak appears at 1421cm^(-1), which dissppears when Pt is loaded on the zeolite, becans of the strong interaction between Pt and Ba^(2+). Thus, the distribution of Pt particles on Pt/BaKL is more uniform than that on Pt/ KL and the size of most Pt particles is from 1.5 to.3.0nm. As a result, the activity and selectivity of Pt/BaKL for aromatization reached about 98%and 95% respectively.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
1992年第3期244-251,共8页
Journal of Fuel Chemistry and Technology
关键词
沸石
Pt/BaKL
芳构化
钡
BaKL zeolite
Pt/BaKL zeolite
function of Ba^(2+)
aromatization
