催化作用
结晶度
化学
钴
氢
程序升温还原
氧化钴
费托法
无定形固体
化学工程
无机化学
镧
多相催化
有机化学
结晶学
选择性
工程类
作者
Chao’en Li,Lisa Wong,Liangguang Tang,Nicola V. Y. Scarlett,Ken Chiang,Jim Patel,Nick Burke,Valérie Sage
标识
DOI:10.1016/j.apcata.2017.02.022
摘要
The reduction activities and mechanisms of cobalt-based catalysts are of great interest to industry and researchers, due to their applications in Fischer–Tropsch synthesis. Here, we investigated the reduction of alumina‐supported cobalt catalysts by hydrogen using temperature-programmed reduction. We propose a five-step reduction mechanism that incorporates both amorphous and crystalline Co3O4, and includes the interaction between CoO and the Al2O3 support. Based on our proposed mechanism, we developed a kinetic model of the reduction process. The modelling results of catalysts promoted with ruthenium and lanthanum in contrast with un-promoted catalyst clearly show that the promoter improves reducibility of the catalyst. The effect of Co3O4 crystallinity was also investigated by the reduction of fresh in comparison of pre-oxidised catalyst. We conclude that high crystallinity significantly increases the difficulty of reducing Co3O4. The interaction between CoO and Al2O3 under reduction conditions to form CoAl2O4 was quantitatively simulated. The kinetic modelling confirms that the support plays an important role in catalyst reduction via the interaction between the catalyst and the support. Those kinetic modelling results are supported by in situ X-ray diffraction studies of the reduction process.
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