有机改性对粘土负载镍催化剂的促进作用及其萘加氢性能(英文)

Promotion of Ni/clay catalytic activity for hydrogenation of naphthalene by organic modification of clay

以有机改性后的十六烷基三甲基溴化铵柱撑蒙脱石(CTAB-MMT)为载体,采用浸渍法制备了Ni/MMT催化剂.通过傅里叶红外光谱、X射线衍射、H2程序升温脱附、N2物理吸附以及紫外漫散射等物理化学手段对催化剂进行了表征;并结合微型高压反应釜萘加氢反应,评价了催化剂的加氢性能.结果表明,有机改性显著改善了Ni/MMT催化剂的金属Ni分散度和织构性质,且所制催化剂表现出优异的萘加氢性能,Ni萘转化率达到88.2%,不仅远高于未处理催化剂(13.1%)和Al2O3柱撑处理催化剂(24.2%),而且高于Ni/SBA-15催化剂(68.2%).鉴于CTAB有机柱撑体在催化剂还原过程因热解而消除,其对催化剂所起的作用主要发生于浸渍过程,提出了有机改性在浸渍过程对Ni/MMT催化剂的促进作用机制.

A Ni/montmorillonite （MMT） catalyst was prepared by an impregnation method using cetyltrime-thylammonium bromide （CTAB）-pillared MMT as the supporting matrix and was characterized using infrared spectroscopy, X-ray diffraction, H2 temperature-programmed desorption, N2 adsorp-tion-desorption, and ultraviolet diffuse reflectance spectroscopy. The catalytic activity of the Ni/MMT for the hydrogenation of naphthalene was also evaluated. The results show that the organ-ic modification of MMT greatly improved the Ni dispersion and textural properties of the Ni/MMT catalyst. The as-prepared Ni/MMT catalyst showed high naphthalene conversion （88.2%） in the hydrogenation reaction; this is much higher than those achieved using Ni supported on pristine MMT （13.1%）, Al2O3-pillared MMT （24.2%）, and SBA-15 （68.2%）. As a result of thermal decomposi-tion of CTAB pillars during reduction of the Ni/MMT catalyst, the CTAB pillars mainly play a role in the Ni/MMT catalyst during impregnation. A mechanism for the promotion of the Ni/MMT catalytic activity by organic modification during impregnation is proposed.