The Zn-Cu(I)/HMCM-41 catalysts were successfully prepared in laboratory scale by solid-state ion exchange with CuCl salt, together with introduction of Zn to improve the dispersion degree of the active component Cu(I)...The Zn-Cu(I)/HMCM-41 catalysts were successfully prepared in laboratory scale by solid-state ion exchange with CuCl salt, together with introduction of Zn to improve the dispersion degree of the active component Cu(I) on the surface. With increase of the amounts of Zn and CuCl from 0% to 9.0% and 25.0% respectively, CO adsorption the amounts of increased from 10.6 mmol/g to 183.0 mmol/g correspondingly. The in situ FT-IR spectra for CO adsorption demonstrated that there existed two dynamic equilibriums between surface carbonyl complexes: Cu(CO)3+ Cu(CO)2++ CO and Cu(CO)2+ Cu(CO)+ + CO. The equilibriums can be shifted reversibly by changing the temperature and pressure. Due to the modified MCM-41 mesoporous materials possess both of the acidic and metallic carbonyl centers, this kind of material can be developed into mesoporous bifunctional catalysts for carbonylation reactions, in which larger molecules are involved.展开更多
制备了不同Al含量的Al-MCM-41试样,其中Si/Al比值最小为3,即最高含铝量xAl=0.303.X射线粉末衍射(XPD)分析表明样品具有MCM-41的特征结构,氮气吸附研究表明,样品呈现Ⅳ型吸附等温线,具有孔径分布均一的中孔结构.文中还利用27Al MAS NM...制备了不同Al含量的Al-MCM-41试样,其中Si/Al比值最小为3,即最高含铝量xAl=0.303.X射线粉末衍射(XPD)分析表明样品具有MCM-41的特征结构,氮气吸附研究表明,样品呈现Ⅳ型吸附等温线,具有孔径分布均一的中孔结构.文中还利用27Al MAS NMR研究了试样中Al的化学环境,结果表明,即使在高铝含量的情况下,样品中的铝原子仍以四配位结合在MCM-41的硅骨架上,未能检测出骨架外六配位铝的存在.文中还就Al含量对孔结构的影响以及Al-MCM-41形成机理作了讨论.展开更多
文摘The Zn-Cu(I)/HMCM-41 catalysts were successfully prepared in laboratory scale by solid-state ion exchange with CuCl salt, together with introduction of Zn to improve the dispersion degree of the active component Cu(I) on the surface. With increase of the amounts of Zn and CuCl from 0% to 9.0% and 25.0% respectively, CO adsorption the amounts of increased from 10.6 mmol/g to 183.0 mmol/g correspondingly. The in situ FT-IR spectra for CO adsorption demonstrated that there existed two dynamic equilibriums between surface carbonyl complexes: Cu(CO)3+ Cu(CO)2++ CO and Cu(CO)2+ Cu(CO)+ + CO. The equilibriums can be shifted reversibly by changing the temperature and pressure. Due to the modified MCM-41 mesoporous materials possess both of the acidic and metallic carbonyl centers, this kind of material can be developed into mesoporous bifunctional catalysts for carbonylation reactions, in which larger molecules are involved.
文摘制备了不同Al含量的Al-MCM-41试样,其中Si/Al比值最小为3,即最高含铝量xAl=0.303.X射线粉末衍射(XPD)分析表明样品具有MCM-41的特征结构,氮气吸附研究表明,样品呈现Ⅳ型吸附等温线,具有孔径分布均一的中孔结构.文中还利用27Al MAS NMR研究了试样中Al的化学环境,结果表明,即使在高铝含量的情况下,样品中的铝原子仍以四配位结合在MCM-41的硅骨架上,未能检测出骨架外六配位铝的存在.文中还就Al含量对孔结构的影响以及Al-MCM-41形成机理作了讨论.