title: Synthesis and catalysis of location-specific cobalt nanoparticles supported by multiwall carbon nanotubes for Fischer-Tropsch synthesis.
abstract: Cobalt nanoparticles located on the concave internal surface of multiwalled carbon nanotubes (Co-in-MW-CNTs) and the convex external surface of MW-CNTs (Co-on-MW-CNTs) were synthesized. Their catalytic performances in Fischer-Tropsch synthesis (FTS) were investigated. A correlation between the location, pretreatment, and surface chemistry of the cobalt nanoparticles and the catalytic selectivity in FTS was built. It is found that the selectivity in production of C(5+) molecules through FTS on cobalt catalysts supported by MW-CNTs depends on activation temperatures and surface chemistry of the cobalt nanoparticles. A pretreatment at 300 °C in H(2) flow results in a different surface chemistry for Co-in-MW-CNTs than for Co-on-MW-CNTs, which leads to a difference in selectvity to the production of C(5+) molecules. Pretreatment at a relatively high temperature, 400 °C, in H(2) flow produces completely reduced Co nanoparticles in Co-in-MW-CNTs and Co-on-MW-CNTs. There is no signifcant difference in catalytic selectivity between the two catalysts upon pretreatment at 400 °C. The absence of a significant difference in catalytic selectivity of metallic Co-on-MW-CNTs and metallic Co-in-MW-CNTs suggests that the electronic effect of the MW-CNT support does not significantly affect the C(5+) selectivity of cobalt catalysts in FTS.
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhu
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Ye
authors.forename: Shiran
authors.initials: S
authors.lastname: Zhang
authors.forename: Mark E
authors.initials: ME
authors.lastname: Leong
authors.forename: Franklin Feng
authors.initials: FF
authors.lastname: Tao