FISCHER-TROPSCH SYNTHESIS OVER COBALT SUPPORTED ON ELECTROSPUN SILICA FIBERS

Abstract

This research aimed to study the preparation of electrospun silica fibers (SF) and using as catalyst support. SF were synthesized from TEOS by a facile combination of sol-gel and electrospinning methods and then used as supports for cobalt catalysts in the Fischer-Tropsch synthesis (FTS) reaction. The optimized condition for SF preparation was a 15 cm TCD and 15 kV applied voltage to produce continuous SF with a submicron diameter of 0.83 µm. Then, SF were modified by in situ hydrothermal synthesis of the zeolite ZSM-5 on the SF (ZSM-5/SF) at 170oC for 24 h. ZSM-5/SF support was used to prepare supported cobalt FTS catalysts. Their catalytic performance in the FTS was tested. The FTS using the ZSM-5 modified SF supported Co catalysts showed a high selectivity to C5˗C11 hydrocarbons with a high CO conversion level. Moreover, different SF supported cobalt catalysts were prepared by impregnation (IM), strong electrostatic adsorption (SEA), deposition precipitation (DP) from either sodium hydroxide (DPNa) or ammonia solution (DPNH), and hydrothermal synthesis (HT). The preparation methods significantly affected the catalytic activity of the obtained catalysts, with their catalytic activity in the FTS reaction being ranked (highest to lowest) in the order of SEA > DPNH = DPNa > IM >> HT. The size of the Co3O4 particles in the cobalt supported on SF catalysts ranged from 4 nm to 30 nm of diameter. The excellent catalytic activity of the Co/SF-SEA catalyst could be attributed to the smaller size of the cobalt particles and their higher dispersion level.