Selective adsorption of manganese onto cobalt for optimized Mn/Co/TiO_2 Fischer-Tropsch catalysts

摘要

The Strong Electrostatic Adsorption (SEA) method was applied to the rational design of a promoted Co catalyst for Fischer-Tropsch (FT) synthesis. A series of Mn/Co/TiO_2 catalysts were prepared by selective deposition of the [MnO_4]~- anion onto the supported Co_3O_4 phase. Qualitative ICP-OES and XPS measurements of the prepared catalysts with increasing Mn loading displayed the preferential association of the Mn species with Co_3O_4 and not the TiO_2 support. The SEA preparation method seemed to minimize the migration of Mn away from the Co to the TiO_2 support during reduction procedures to ensure a more intimate interaction between the Mn and the Co species during FT reactivity measurements. This led to an increase in light olefins, C_(5+) selectivity and chain growth probability. It is anticipated that the SEA preparation method is a viable synthesis strategy for other promoted and/or bimetallic catalyst systems where intimate contact between the catalyst components is highly desired.