【摘要】 研究了粒径为 1 5～ 1 8nm的纳米 Zr O2 -AS负载 Ni催化剂对 CO2 重整 CH4制合成气的催化性能 ,结果表明 ,Ni/Zr O2 -AS催化剂对重整反应的超常稳定催化作用不受 Ni含量的影响 ,但当 Ni质量分数低于1 0 %时 ,催化剂活性随 Ni含量增加而显著上升 ,此后 ,CH4和 CO2 的转化逐渐接近其热力学平衡值 .高空速虽然降低了反应物的转化率 ,但可得到更高的时空产率 .各种表征数据揭示 ,Ni/Zr O2 在结构上有别于传统的负载型催化剂 ,可看成是由尺寸相当 ( 1 0～ 2 0 nm)的纳米金属 Ni和纳米 Zr O2 形成的纳米复合物催化剂 .更多还原

【Abstract】 Ni "supported" nano-zirconia catalyst(named as Ni/ZrO 2-AS) was extremely stable for CO 2 reforming of CH 4 to syngas. In the present work, the effects of the Ni loading(5%-32%), reaction temperature(923-1 123 K) and space velocity[GHSV=10 4-10 5 mL/(h·g-cat)] were extensively studied. While the catalytic stability of Ni/ZrO 2-AS catalysts seemed not significantly affected by the Ni loading, the increase of the loading up to 10% improved effectively the catalyst activity at 1 030 K. In the reactions over the catalysts with higher Ni loadings, the conversions of the reactants approached their values for thermodynamic equilibrium. The increase of the feed space velocity led to a decrease of the reactant conversions, but to an increase of the space time yield of syngas product. TPO measurement of the carbon deposition showed that every nickel atoms in the catalysts survived dynamically two carbon atoms on the average. TPR/TPD and TEM characterizations revealed that Ni/ZiOr 2-AS catalysts were different in structure from conventional metal catalysts supported on porous oxides; they were nano-composites of size-comparable metallic Ni and ZrO 2 nanocrystals( 10- 20 nm). The catalytic stability of Ni catalysts in Ni/ZrO 2-AS system is most probably connected with the nature of the nanoacomposite structures.更多还原