Pd/γ-Al_2O_3催化剂催化氧化邻-二甲苯  

Catalytic Oxidation of o-Xylene over Pd/γ-Al_2O_3 Catalysts

作　　者：胡凌霄[1,2] 王莲[1,2] 王飞[1,2] 张长斌[1,2] 贺泓[1,2,3] 

机构地区：[1]中国科学院生态环境研究中心环境模拟与污染控制国家重点联合实验室,北京100085 [2]中国科学院大学,北京100049 [3]中国科学院城市环境研究所,福建厦门361021

出　　处：《物理化学学报》2017年第8期1681-1688,共8页Acta Physico-Chimica Sinica

基　　金：优秀青年基金(21422706);国家自然科学基金(51678560)项目资助~~

摘　　要：利用纳米γ-Al_2O_3(10 nm)和普通γ-Al_2O_3(200-300 nm),采用浸渍法制备了1%(w)Pd/γ-Al_2O_3催化剂,考察了其催化氧化邻-二甲苯的性能以及催化剂的活性在氢气还原前后的区别。实验结果发现1%(w)Pd/γ-Al_2O_3(nano)在H_2还原后催化氧化邻-二甲苯的活性最高,T_(90)为150℃。利用X射线衍射(XRD)、比表面积(BET)、透射电镜(TEM)、X射线光电子能谱(XPS)等表征手段,研究了1%(w)Pd/γ-Al_2O_3催化剂物性结构与催化性能之间的构效关系。结果表明,还原态Pd是H_2还原后催化剂催化氧化邻-二甲苯的活性物种;Pd的颗粒大小与催化剂活性有显著的关系,小粒径有利于催化剂活性提高;纳米γ-Al_2O_3载体与Pd之间的相互作用强,有利于Pd的粒径控制和分散,从而提高1%(w)Pd/γ-Al_2O_3(nano)催化剂的活性。1% （w）Pd/γ-Al2O3 catalysts were prepared by the impregnation method using nano γ-Al2O3 （10 nm） and γ-Al2O3 （200-300 nm） as support materials. The catalysts were tested for catalytic oxidation of o-xylene and the difference of catalyst activity before and after hydrogen reduction was investigated. The results indicate that 1% （w）Pd/γ-Al2O3 （nano） has the highest catalytic activity for o-xylene oxidation after H2 reduction, and the T90 （The temperature of conversion rate of o-xylene reaches 90%） was 150℃. The structure-activity relationships of the catalysts were studied by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and X-ray photoelectron spectroscopy （XPS）, while the specific surface area was determined using the Brunauer-Emmett-Teller （BET） isotherm. The results show that the reduced Pd is the active species for catalytic oxidation of o-xylene. Pd particle size has a significant influence on the catalyst activity and a small Pd particle size is favorable. There is a strong interaction between the supporter （nano γ-Al2O3） and the Pd species, which facilitates the particle size control and Pd dispersion, thereby increasing the catalyst activity of the 1% （w）Pd/γ-Al2O3（nano） catalyst.

关 键 词：Γ-AL2O3 贵金属催化剂 催化氧化 邻-二甲苯 

分 类 号：O643.36[理学—物理化学]