Catalytic upgrading of long-chain 1-alkene in synthetic fuels over shape-controlled cobalt oxide nanocrystals

摘要

To upgrade odd numbered a-olefins derived from FTS residues, the heterogeneous hydroformylation of 1-heptene as a model compound for odd numbered a-olefin was investigated. Single crystalline Co3O4 nano catalysts with different morphologies (cube and octahedron) were synthesized using a hydrothermal method and were applied to the reductive hydroformylation of 1-heptene. HRTEM and SEM analysis indicated that the cubic and octahedral Co3O4 predominantly exposed well-defined crystal planes of {100} and {111}, respectively. The Co3O4 octahedron catalyst with highly exposed {111} facets had higher activity for hydroformylation than the Co3O4 cube catalyst. The Co3O4 octahedron catalyst with a {111} surface was easily reduced to CoO at lower temperature. These reduced cobalt species can be converted into cobalt carbonyl and improved reactivity with carbon monoxide, hydrogen and olefin, leading to better catalytic performance for hydroformylation than Co3O4. On the other hand, the Co3O4 cube catalyst with the {100} surface only exhibited the isomerization of 1-heptene.