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介孔二氧化硅泡沫(MCFs)材料具有超大的三维球形孔结构、超大孔容(1.0–2.4 cm~3/g)、高比表面(1000 m~2/g)、孔径可调范围较广(24–50 nm)且球形孔道之间通过窗口(9–22 nm)联结,因此具有优良的传质性能,能够促进加氢脱硫反应.但是,与传统的微孔分子筛相比,该纯硅类介孔材料酸性较弱,不利于一些酸催化反应;因此,对纯硅材料进行金属改性以增加其酸性,从而促进催化剂的催化活性.而一般对纯硅类介孔材料采用Al,Ti,Zr等金属,铝改性主要是为纯硅载体提供酸性,而钛锆改性则是为了调变活性金属以及促进金属的分散,从而提高催化剂的加氢脱硫活性.因此,我们主要采用后改性方法,以P123为微乳液体系中的表面活性剂,TEOS为硅源,TMB为扩孔剂,异丙醇铝为铝源,成功合成了一系列Si/Al比不同的介孔二氧化硅泡沫材料.通过改变异丙醇铝的加入量,成功合成了系列Si/Al比(x)的NiMo/Al-MCFs(x)(x=10,20,30,40和50)催化剂.对所合成的载体及相应的催化剂通过SAXS,N_2吸附脱附,SEM,Py-FTIR,UV-Vis,H_2-TPR,NH3-TPD,HRTEM,Raman及~(27)Al MAS NMR等表征手段进行分析,并在高压加氢微反装置上对相应的NiMo负载型催化剂进行DBT HDS活性评价,系统分析了不同硅铝比对催化剂DBT HDS反应活性的影响.SAXS和SEM表征结果表明,Al后改性并没有破坏载体材料的结构;~(27)Al MAS NMR表征结果表明,后改性法能成功把Al掺杂进纯硅材料的骨架中.催化剂UV-Vis和Raman表征结果表明,当Si/Al比为20时,NiMo/Al-MCFs(20)催化剂Mo物种的带隙能量最大,且氧化钼的平均粒径较小,Mo物种在该催化剂中的分散度较好;H_2-TPR分析结果表明,NiMo/Al-MCFs(20)催化剂还原温度较低,最易还原.Py-FTIR结果表明,随着Al加入量的增大,其酸性逐渐增大,当Si/Al比为20时酸性达到最大,继续增加Al的加入量,其酸性不再增加;此外,NiMo/Al-MCFs(20)的硫化度最高,且其MoS_2的堆垛层数较低.负载活性金属后制备了NiM o/Al-MCFs(x)催化剂,将其应用于DBT加氢脱硫反应,并与传统NiM o/γ-Al_2O_3催化剂加氢脱硫反应活性作对比.研究发现,所制备的NiMo/Al-MCFs(x)系列催化剂由于具有较大孔径、比表面积及孔容和较强的酸性,因而其DBT HDS活性明显高于传统的工业NiMo/g-Al_2O_3催化剂,且催化剂活性在硅铝比达到20时最大,最高可达96%,因此它作为加氢脱硫催化剂载体具有很大的应用前景.
Mesoporous silica foam (MCFs) has a large three-dimensional spherical pore structure, with large pore volume (1.0-2.4 cm 3 / g) and high specific surface area (1000 m 2 / g) (24-50 nm), and the spherical pores are connected through the window (9-22 nm), so it has excellent mass transfer performance and can promote the hydrodesulfurization reaction.However, compared with the traditional microporous molecular sieves, the pure silicon Mesoporous materials with weak acidity are not conducive to some acid-catalyzed reactions; therefore, the pure silicon materials are modified with metals to increase their acidity, thereby promoting the catalytic activity of the catalysts. However, the general use of pure silicon mesoporous materials Al, Ti , Zr and other metals, aluminum modification is mainly to provide pure silica carrier acid, and titanium zirconium modification is to change the active metal and promote the dispersion of metal, thereby enhancing the catalyst hydrodesulfurization activity.Therefore, we mainly use after The modified method is as follows: P123 is a surfactant in microemulsion system, TEOS is a silicon source, TMB is a pore-expanding agent and aluminum isopropoxide is an aluminum source. A series of mesoporous dioxins Si foam material.A series of Si / Al ratio (x) NiMo / Al-MCFs (x) (x = 10, 20, 30, 40 and 50) .The catalytic activity of the synthesized catalyst and its corresponding catalyst were investigated by SAXS, N 2 adsorption and desorption, SEM, Py-FTIR, TPR, NH3-TPD, HRTEM, Raman and ~ (27) Al MAS NMR. The DBT HDS activities of the corresponding NiMo supported catalysts were evaluated on a high pressure hydrogenation micro-reactor. Aluminum ratio on the catalytic activity of DBT HDS.SAXS and SEM characterization results show that Al modified after did not destroy the structure of the support material; ~ (27) Al MAS NMR characterization results show that post-modification method can successfully Al doped The results of UV-Vis and Raman characterization show that the bandgap energies of Mo species in NiMo / Al-MCFs (20) catalyst are the largest when the Si / Al ratio is 20, and the average The results of H 2 -TPR analysis showed that the reduction temperature of NiMo / Al-MCFs (20) catalyst was the lowest and the easiest to reduce.The results of Py-FTIR showed that with the increase of The acidity of NiMo / Al-MCFs (20) increased gradually with the increase of Al addition. The acidity reached the maximum when the Si / Al ratio was 20 and the addition of Al continued. NiMo / Al-MCFs (x) catalysts were prepared by loading active metals and then applied to the DBT hydrodesulfurization reaction. Compared with the conventional NiM o / γ- Al 2 O 3 catalyst for hydrodesulfurization was compared.It was found that the prepared NiMo / Al-MCFs (x) series catalyst had a significantly higher DBT HDS activity due to its larger pore size, specific surface area and pore volume and stronger acidity In the traditional industrial NiMo / g-Al 2 O 3 catalyst, the catalyst activity is the largest, up to 96% when the Si / Al ratio reaches 20, so it has great application prospects as a catalyst for hydrodesulfurization.