Propane Dehydrogenation over Pt/TiO2-Al2O3 Catalysts
Propane Dehydrogenation over Pt/TiO2-Al2O3 Catalysts
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Pt/TiO2-Al2O3 催化剂上的丙烷脱氢
DOI：
10.1021/cs501279v
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发表时间：
2015-01-01
期刊：
影响因子：
12.9
通讯作者：
Gong, Jinlong
中科院分区：
文献类型：
--
作者：
Jiang, Feng;Zeng, Liang;Gong, Jinlong
本文描述了一项研究，以了解负载在TiO2Al2O3二元氧化物上的Pt纳米颗粒对丙烷脱氢（PDH）的催化作用。采用溶胶法制备TiO2Al2O3载体，采用初湿浸渍法制备Pt/TiO2Al2O3催化剂。采用N-2吸附解吸、x射线衍射、拉曼光谱、H2O2滴定、程序升温解吸、热重分析、程序升温氧化、透射电镜和傅里叶变换红外光谱对制备的催化剂和实验后的催化剂进行了表征。结果表明，TiO2在Al2O3上高度分散，适量的TiO2的加入提高了丙烯的选择性和催化稳定性。这是由于电子从部分还原的TiOx （x < 2）转移到Pt原子。增加Pt的电子密度可以减少丙烯的吸附，促进焦炭前驱体从金属表面向载体的迁移。然而，TiO2的加入也增加了载体上强酸中心的数量，过量的TiO2添加可能导致大量的焦炭形成。TiO2的电子转移效应和酸位效应对催化性能的影响相反。通过改变TiO2的负载量，研究了电子转移效应和酸位效应之间的权衡。TiO2的最佳负载量为10 wt %，具有较高的丙烯选择性和较好的稳定性。
This paper describes an investigation on understanding catalytic consequences of Pt nanoparticles supported on a TiO2Al2O3 binary oxide for propane dehydrogenation (PDH). The TiO2Al2O3 supports were synthesized by a solgel method, and the Pt/TiO2Al2O3 catalysts were prepared by an incipient wetness impregnation method. Both as-prepared and post-experiment catalysts were characterized employing N-2 adsorptiondesorption, X-ray diffraction, Raman spectra, H2O2 titration, temperature-programmed desorption, thermogravimetric analysis, temperature-programmed oxidation, transmission electron microscopy, and Fourier-transform infrared spectra of chemisorbed CO. We have shown that TiO2 is highly dispersed on Al2O3, and the addition of appropriate amount of TiO2 improves propylene selectivity and catalytic stability, which is ascribed to the electron transfer from partially reduced TiOx (x < 2) to Pt atoms. The increased electron density of Pt could reduce the adsorption of propylene and facilitate the migration of coke precursors from the metal surface to the support. The addition of TiO2, however, also increases the amount of strong acid centers on the supports and the excessive TiO2 addition might lead to a significant amount of coke formation. The electron transfer effect and the acid sites effect of TiO2 addition exert an opposite influence on catalytic performance. The trade-off between the electron transfer effect and the acid sites effect is studied by varying the amount of TiO2 loading. An optimal loading content of TiO2 is 10 wt %, which results in a higher propylene selectivity and a better stability.