Increasing the shell thickness by controlling the core size of zeolite capsule catalyst: Application in iso-paraffin direct synthesis

Three kinds of H-ZSM-5 zeolite capsule catalysts were prepared on Ru/SiO2 catalyst pellets with different size. Characterization indicated that defect-free H-ZSM-5 capsule had been constructed on the Ru/SiO2 surface successfully. And small Ru/SiO2 pellet with large external surface was favorable for zeolite capsule growth under the same zeolite synthesis conditions. In the iso-paraffin direct synthesis via Fischer–Tropsch synthesis (FTS) reaction, zeolite capsule catalysts, especially the one with smaller pellet size, realized the higher iso-paraffin selectivity comparing with conventional FTS Ru/SiO2 catalyst, and physically mixed catalyst of Ru/SiO2 with H-ZSM-5 zeolite.