不同形态ZrO_2负载Co催化剂上CO+H_2吸附与反应行为研究

Adsorption and Reaction Behavior over Co Catalysts Supported by Different Zirconia Polymorphs

利用FTIR,TPSR和微量反应技术考察了CO和CO/H2在无定形、四方相和单斜相3种形态氧化锆为载体的钴基催化剂上的吸附和反应行为.结果表明,CO在以不同形态氧化锆为载体的催化剂上的吸附形式和转化行为具有较大差异.在单斜氧化锆为载体的催化剂上生成桥式和多桥式吸附的CO,并容易进一步加氢生成烃类物种,具有较高的反应活性和C+5烃的选择性.而以四方氧化锆为载体的催化剂上桥式吸附的CO较稳定,加氢反应活性较低.

CO and CO/H_2 adsorption and reaction behavior over Co catalysts with amorphous, tetragonal and monoclinic zirconia as the supports were characterized by FTIR, TPSR and Fisher-Tropsch synthesis. The results show that cobalt catalysts with different zirconia polymorphs as the supports exhibited various behavior of CO adsorption and reaction. For the Co catalyst supported on monoclinic zirconia, besides the multi terminal CO, bridged and tribridged CO appeared and were easily dissocia-(ted) at a high temperature, which resulted in the higher catalytic behavior and C^+__5 selectivity in the case of CO hydrogenation. While for cobalt supported on tetragonal zirconia, the bridged CO was more stable and CO hydrogenation was relatively less active.