纳米ZrO_2负载Ni催化剂催化CO选择性甲烷化

Selective Methanation of CO over Ni-Based Catalysts Supported on Nano-Zirconia

利用表面活性剂辅助模板机理,结合水热法合成出纳米有序的多孔 ZrO_2载体,采用等体积浸渍法制备了 Ni/ZrO_2催化剂;采用固定床微反装置评价了 Ni/ZrO_2催化剂对富氢气体中低含量 CO 选择性甲烷化反应的催化性能;采用 X 射线衍射和程序升温还原等方法对载体和催化剂进行了表征。实验结果表明,利用模板剂十六烷基三甲基溴化铵(CTAB)制备的 ZrO_2载体再负载质量分数4%Ni 的 Ni/ZrO_2催化剂具有优异的催化活性,可将 CO 体积分数从1.1%降至0.01%以下,且该催化剂在220～260℃内均能保持较高的活性和选择性。表征结果显示,以 CTAB 为模板剂制备的多孔性纳米 ZrO_2具备优良的载体性能,能促进活性组分 Ni 的分散,载体与活性组分 Ni 之间存在较强的相互作用,提高了催化剂的活性。

A series of Ni/ZrO2 catalysts were prepared by incipient wetness impregnation. The support, an ordered porous nano-zirconia, was synthesized by hydrothermal method aided by a surfactant as template. Effects of metal loading amount and addition of cetyltrimethylammonium bromide（CTAB） template on activities of Ni/ZrO2 catalysts were investigated. Catalysts with 4% （mass fraction）Ni supported on ZrO2 which were prepared with or without CTAB template（ written as Ni/ZrO2 （A） and Ni/ZrO2 （B））were studied. Selective methanation of CO in the presence of Ha and CO2 was chosen as probe reaction to evaluate activity and selectivity of the Ni/ZrO2 catalysts. Ni/ZrO2 （A） catalyst exhibits excellent catalytic activity and selectivity. It shows the capability of reducing CO content in feedstock gas to less than 0.01% （ volume fraction） over a wide temperature range from 220 ℃ to 260 ℃. keeping a high selectivity at the same time. ZrO2 support prepared with CTAB can promote the dispersion of active Ni component, strengthen interaction between Ni and the support, and prevent the accumulation of Ni, so endow the Ni/ZrO2 （A） catalyst with excellent catalytic activity.