载体表面性质调控Pt⁃Sn/γ⁃Al2O3催化剂丙烷脱氢性能

Control of Propane Dehydrogenation Performance of Pt⁃Sn/γ⁃Al2O3 Catalysts by Support Surface Properties

崔明彧 焦建豪 康津铭 刘世佳 关慧敏 宋丽娟

Mingyu Cui Jianhao Jiao Jinming Kang Shijia Liu Huimin Guan Lijuan Song

辽宁石油化工大学 石油化工学院，辽宁 抚顺 113001 中国石油大学（华东） 化学工程学院，山东 青岛 266000

School of Petrochemical Engineering，Liaoning Petrochemical University，Fushun Liaoning 113001，China School of Chemical Engineering，China University of Petroleum，Qingdao Shandong 266000，China

Al2O3载体的性质是影响丙烷脱氢Pt?Sn/γ?Al2O3催化剂性能的关键因素。采用450、650、850 ℃三种焙烧温度制备了γ?Al2O3载体，运用XRD、XRF、NH3?TPD、Py?FTIR、CO?FTIR、OH?FTIR等表征手段系统研究了载体和其负载型催化剂的结构和性质，使用固定床在线分析微型反应装置评价了丙烷脱氢反应性能，并对气相产物分布和结焦性质进行了分析。结果表明，随着焙烧温度的升高，γ?Al2O3载体的表面酸量减少，850 ℃高温焙烧几乎完全消除了表面弱L酸中心，这说明γ?Al2O3表面配位不饱和Al位点和表面-OH数量随焙烧温度的升高而减少，这一特征不利于金属活性中心的高度分散；CO?FTIR和TEM表征结果均证实了在Pt?Sn/γ?Al2O3?850催化剂上形成了更大的Pt团簇，更多的饱和配位Pt活性相结构会促进深度脱氢等副反应的发生，降低丙烯产物的选择性。

The properties of alumina supports are the key factors affecting the propane dehydrogenation performance of Pt?Sn/γ?Al2O3 catalysts.In this paper,γ?Al2O3 supports were prepared at three calcination temperatures of 450,650,850 ℃,and the structures and properties of the supports and supported catalysts were systematically studied by XRD,XRF,NH3?TPD,Py?FTIR, CO?FTIR,OH?FTIR,and other characterization methods.The properties of the propane dehydrogenation reaction were evaluated by a fixed?bed micro?reaction evaluation device with online analysis,and the gas?phase product distribution and coking properties were analyzed.The results show that with the increase in calcination temperature,the surface acid content of γ?Al2O3 supports decreases,and calcination at 850 ℃ almost eliminates the weak L acid centers on the surface.This indicates that the number of coordinated unsaturated Al sites on the surface of γ?Al2O3 and surface hydroxyl groups decreases as the calcination temperature grows,which is not conducive to the high dispersion of metal active centers.Both CO?FTIR and TEM results confirm the formation of larger Pt clusters on Pt?Sn/γ?Al2O3?850,and more Pt active phase structure with saturated coordination can promote the occurrence of side reactions such as deep dehydrogenation and reduce the selectivity of propylene products.

国家自然科学基金项目(U1908203)

10.12422/j.issn.1006-396X.2023.01.006