PtZn-Sn/SBA-15合成、表征及对丙烷催化脱氢性能

以SBA-15为载体,利用浸渍法制备了单、双和三金属Pt催化剂,并对催化剂进行了N2物理吸附(BET)、程序升温还原(H2-TPR)、H2-化学吸附、透射电子显微镜(TEM)和O2-脉冲等技术表征,研究了它们对丙烷催化脱氢(CDH)制丙烯反应的催化性能。研究结果表明,Pt在三金属催化剂中的分散性能最好,并且部分负载组分可以进入SBA-15的孔道,Pt的分散度达到29%,Pt粒子尺寸为3 nm左右。三金属催化剂表现出优越的脱氢性能,这主要归结于载体的弱酸性、活性组分和助剂、载体之间的相互作用及Zn对Pt的电子调控作用。这些因素使催化剂的积炭量较低,因而具有较高的脱氢稳定性和极高的选择性。

Preparation, characterization, and catalytic performance of PtZn-Sn/SBA-15 catalyst for propane dehydrogenation

The mono-, dual- and tri-metallic Pt catalysts for the catalytic dehydrogenation of propane to propylene were prepared by impregnation method using SBA-15 as the support. The fresh catalysts were characterized by some physicochemical characterizations such as BET, H₂-TPR, H₂-chemical adsorption, and TEM. The amount of deposited carbon on used catalysts was analyzed by O₂-pulse technology. The results show that the highest dispersion (about 29%) and the smallest particles size (about 3nm) of Pt are obtained over the trimetallic Pt catalyst. Over the trimetallic catalyst, the loading components can enter the pore of the SBA-15.The tri-metallic Pt catalyst shows the excellent catalytic dehydrogenation performance. The main reasons are the very weak acidity of support, the strong interactions between Pt, promoter, and the support, and the electronic modifications of the Zn to Pt, which can reduce the coke reaction, promote the stability, and selectivity of PtZn-Sn/SBA-15 catalyst in dehydrogenation of propane.