预处理气氛对Co-ZrO_2共沉淀催化剂结构的影响

Effect of Pretreatment Atmospheres on the Structure of the Co-ZrO_2 Catalyst Prepared by Precipitation Method

考察了共沉淀Co-ZrO2催化剂在不同气氛(Ar、H2、CO和CO+H2)、不同温度下处理后,催化剂织构、晶相以及形貌的变化规律．结果表明,在惰性气氛或氢气氛处理过程中,催化剂在500℃以上发生明显烧结．经上述处理并暴露于空气后,催化剂中钴物种均以Co3O4形式存在,且催化剂粒子外形无明显变化．CO气氛还原使催化剂破碎严重,同时发生明显的积碳现象,催化剂中钴物种以面心单质钴为主要形式．合成气处理对催化剂破坏行为不明显,但催化剂烧结现象严重,催化剂中Co物种以面心立方和六方两种晶型共存．

Co-ZrO2 co-precipitation catalysts were used to investigate the effect of the pretreatment atmosphere on the texture, crystal phase, and morphology of catalysts. The result indicated that the catalysts were sintered evidently above 500 ℃ in Ar and H2 atmospheres. After the pretreated catalysts were exposed to air, all the cobalt species were in existence as CosO4 phase and the particle shape of the catalysts changed little. The pretreatment in CO atmosphere led to serious cracking and obvious coke deposition, and the catalyst mainly contained the cubic cobalt species. The pretreatment of the catalyst with syngas gave rise to serious sintering and trace of fragmentation, and it was found that the cubic and hexagonal cobalt co-existed in the catalyst.