表面活性剂改性Mo-Ni-NH3/γ-Al2O3催化剂的分散性及孔结构的表征

Characterization of Dispersity and Pore Structure of Surfactants-modified Mo-Ni-NH_3/γ-Al_2O_3 Catalysts

采用纳米自组装方法以钼镍铵溶液作为浸渍液制备贯穿性介孔Mo-Ni-NH3/γ-Al2O3催化剂。利用BET比表面积测试法（BET）、CO吸附原位红外、X射线衍射（XRD）、透射电子显微镜（TEM）等表征手段,考察了表面活性剂、助溶剂种类、用量在自组装过程中对催化剂的分散性及孔结构的影响。结果表明,改性后催化剂TOP-3的孔性质最好,其比表面积为183 m^2·g^-1,孔容为0.46 m^3·g^-1,平均孔径为10.11 nm,且孔道在10-30 nm处高度集中,高达35.63%;红外CO原位吸附结果证明了Mo^2＋,Mo^4＋和Ni^2＋活性中心的存在,且均以线式吸附态吸附CO;从XRD分析可发现催化剂NOP-3、NOP-4在2θ=15.9°,20.8°,22.2°和30.8°处出现了Al2（Mo O4）3的（111）,（102）,（021）,（312）4个晶面的特征衍射峰,而TOP系列催化剂的特征峰弥散,说明TEA与OP-20复配可以改善金属的分散性。TEM表征结果证明了15-20 nm贯穿性多孔结构的存在,且分散均匀。此结构有利于大分子扩散,适合于重油加氢处理。

Using Mo-Ni-NH3 as impregnation solution,the penetrating mesoporous Mo-Ni-NH3/ γ-Al2O3 catalyst was prepared by nano self-assembly technique.The influence of dosage of different surfactants such as CTAB,OP-20,TW-80,OP-10,assistantagentia TEA and NS on dispersity and pore structure of catalyst in the process of self-assembly was investigated by BET,insitu FTIR of adsorbed CO,XRD and TEM.The results showed that the modified catalyst TOP-3was better than the others,which has a specific surface area of 183 m^2·g^-1,a pore volume of 0.46m^3·g^-1and an average pore size of 10.11 nm,and its pore distribution of 10 nm-30 nm was greatly concentrated,and reached up to 35.63%.The adsorption of active site of Mo^2 ＋,Mo^4 ＋and Ni^2 ＋was at the presence of linear adsorption state which could be proved by the in-situ FTIR of adsorbed CO.There were four characteristic crystal plane diffraction peaks of（111）,（102）,（021） and（312） for Al2（Mo O4）3at 15.9°,20.8°,22.2° and 30.8° by the XRD analysis for NOP-3 and NOP-4.While the fact that the characteristic peaks of TOP catalysts were dispersive showed that the composites of TEA and OP-20 improved the dispersity obviously.The penetrating mesoporous structures in uniform dispersion between 15 nm and 20 nm could be obtained by TEM images.The structure features were beneficial to residue hydrotreating.