Role of mesopores in Co/ZSM-5 for the direct synthesis of liquid fuel by Fischer–Tropsch synthesis
In a complex reaction system, in which gas, liquid, and solid catalysts work together, understanding the impact of mass transfer that varies with the catalyst pore structure is very challenging but also essential to designing selective catalysts. We investigated the effect of mesopores introduced into bi-functional Co/ZSM-5 catalysts on the direct production of liquid fuel by low-temperature Fischer–Tropsch synthesis (FTS). The influence of mesopores on the textural properties, Co dispersion, zeolite crystallinity, the density of acid sites, and the resulting FTS performance was studied in detail. The presence of mesopores facilitated the dispersion of Co nanoparticles and the regulation of acidity, affording high CO conversion and a moderate degree of isomerization. In addition, close proximity between FTS active sites and acid functionalized sites could be achieved by the introduction of mesopores. However, the relationship between the structural parameter and liquid fuel productivity suggested that the mesopores did not reduce the mass transfer resistance of the reactants and intermediates during the FTS reaction.