Effect of mesoporous ZSM-5 morphology on the catalytic performance of cobalt catalyst for Fischer-Tropsch synthesis

Abstract Mesoporous ZSM-5 with various morphologies loading cobalt were prepared and applied in Fischer-Tropsch synthesis. Smaller ZSM-5 particles showed higher intensity of strong acid sites resulting in higher cobalt-support interaction. The activity and CH4 selectivity were remarkably related with cobalt-support interaction over such acidic supports. Cobalt loaded on spindle mesoporous ZSM-5 exhibited the lowest activity and the highest CH4 selectivity due to the strongest cobalt-support interaction, but the highest activity was obtained over cubic mesoporous ZSM-5 with the lowest cobalt-support interaction originating from weaker acid sites. In addition, adjusting acid intensity and mesopore volumes could successfully tuned hydrocarbon distribution. Spherical ZSM-5 with hierarchical structure containing larger mesopore volumes and moderate acid intensity effectively promoted the production of C12-18 hydrocarbons. The highest C5-11 selectivity was observed over cobalt supported on hexagonal meso-ZSM-5 due to the enhancement in diffusion limitation over lower mesopore volumes and hydrocracking of primary hydrocarbons over higher Bronsted acid sites.