载体类型对Ni基催化剂甲烷干重整反应性能的影响

以不同载体负载NiO制备了甲烷干重整催化剂并对所制备的催化剂采用等温氮气吸附、XRD、H₂-TPR、H₂化学吸附等进行了表征。结果表明,载体性质对NiO的存在状态影响较大。SiO₂、TiO₂以及ZrO₂与NiO的相互作用较弱,催化剂易于被还原活化,而正是由于其与NiO的弱相互作用,导致活性金属在反应过程中易迁移聚集而失活。Al₂O₃和MgO均与NiO有强相互作用,易分别生成NiAl₂O₄尖晶石和NiO-MgO固溶体,导致其难以被还原活化。经MgO改性的Al₂O₃载体不仅具有较大的比表面积,而且与NiO的相互作用强度适中,这有利于NiO的分散和稳定,以其为载体制备的催化剂在较高空速下表现出优异的催化反应活性和稳定性,催化剂连续稳定运行100h不失活。

Effect of support on catalytic performance of Ni-based catayst in methane dry reforming

Ni-based catalysts with different supports were prepared for methane dry reforming. The obtained catalysts were characterized by N₂ physisorption, XRD, H₂-TPR, H₂-chemisorption, and so on. It was revealed that the support had significant influence on the state of NiO species. SiO₂, TiO₂ and ZrO₂ had weak interaction with NiO, facilitating the reduction of the corresponding catalysts. Al₂O₃ and MgO have strong interaction with NiO, making them very difficult to be reduced. Al₂O₃ modified by MgO has both proper texture properties and interaction strength between metal and support, which were in favor of the dispersion and stabilization of NiO species. Superior catalytic performance was observed over this catalyst under very high gas hourly space velocity. Stable catalytic performance was achieved during a long term run of more than 100h.