Abstract

The preparation of bifunctional catalysts with high catalytic selectivity for the n-alkanes hydroisomerization still remains challenging for the production of bio-diesel. Herein, two series of Pd/SAPO-41 bifunctional catalysts are prepared by the ultrasonic-assisted impregnation (xPd/S41-U) with different treating time and conventional incipient wetness impregnation methods (0.30Pd/S41-I) on the SAPO-41 molecular sieve, respectively. The physico-chemical property of the synthesized SAPO-41 and prepared catalysts were studied by XRD, SEM, ICP, N₂ physical adsorption, H₂ chemisorption and Py-IR measurements. The catalytic performance for the n-hexadecane hydroisomerization over all catalysts is also studied. The characteristic results indicate that the xPd/S41-U catalysts show stronger Brønsted acidity compared with the 0.30Pd/S41-I catalyst. In addition, the Pd dispersion of the xPd/S41-U catalysts is almost two times higher than that of the 0.30Pd/S41-I catalyst, which leads more Pd cluster to enter into the micropores of the SAPO-41 molecular sieve. Furthermore, the 0.30Pd/S41-U catalyst with 0.30 wt % Pd loading shows promoted catalytic performance than that of the 0.30Pd/S41-I catalyst with the same Pd loading because of the stronger metal function and more favourable metal-acid balance caused by the larger C_Pd/C_H+ ratio. Therefore, the ultrasonic-assisted impregnation prepared Pd/SAPO-41 catalysts are potential to be widely employed for the n-alkane hydroisomerization.

中文翻译：

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通过超声辅助浸渍制备的具有增强的Pd分散性的Pd / SAPO-41双功能催化剂：对正十六烷加氢异构化的高选择性

摘要

对正烷烃加氢异构化具有高催化选择性的双功能催化剂的制备对于生物柴油的生产仍然具有挑战性。在此，通过在不同的处理时间下用超声辅助浸渍（x Pd / S41-U）和在SAPO-上常规的初湿浸渍方法（0.30Pd / S41-I）制备了两种系列的Pd / SAPO-41双功能催化剂。分别为41个分子筛。通过XRD，SEM，ICP，N ₂物理吸附，H ₂化学吸附和Py-IR测量研究了合成的SAPO-41和制备的催化剂的理化性质。n的催化性能还研究了在所有催化剂上的十六烷加氢异构化。特征结果表明，与0.30Pd / S41-I催化剂相比，x Pd / S41-U催化剂显示出更强的布朗斯台德酸度。另外，x Pd / S41-U催化剂的Pd分散度几乎是0.30Pd / S41-I催化剂的Pd分散度的两倍，这导致更多的Pd团簇进入SAPO-41分子筛的微孔。此外，具有0.30 wt％Pd负载的0.30Pd / S41-U催化剂显示出比具有相同Pd负载的0.30Pd / S41-I催化剂更高的催化性能，这是因为其更强的金属功能和更有利的金属酸平衡由较大的C _Pd / C _{H +}比。因此，超声辅助浸渍制备的Pd / SAPO-41催化剂有可能被广泛用于正构烷烃加氢异构化。