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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 effect of Ba 2+ on Pt / BaKL zeolite was investigated by XRD, NH_3-TPD, IR and TEM. The results of NH_3-TPD show that the acidity of the L-type zeolite exchanged with Ba 2+ is only slightly changed in the weak acid range due to the action of the cation, but there is no obvious corresponding relationship between the catalytic activity and the catalytic activity of the zeolite. The results of IR and XRD showed that the Ba 2+ in BaKL zeolite was in the pore of zeolite B and C with the increase of pre-calcination temperature at the optimal exchange degree of 26.3% D position, close to the best distribution, IR spectrum at 1421cm ~ (-1) at a new peak. When the zeolite is loaded with platinum, the new peak disappears due to the interaction between platinum and Ba ~ (2+), resulting in a more uniform distribution of the platinum particles on the zeolite; the maximum proportion of platinum particles in the 1.5-3.0 nm occupies the largest proportion of Pt / BaKL Zeolites exhibit aromatization activity and selectivity higher than Pt / KL zeolites, ~ 98% and ~ 95%, respectively.