The effect of particle size of silica

as catalyst binder

on the chemical and mechanical properties of iron based FT catalyst was studied in this work. The samples were characterized using XRD

BET

TEM

FT-IR

and H2-TPR

respectively. The attrition resistance and the FT activity were tested. Si-8-Si-15 catalysts prepared with 8-15 nm silica sol show good attrition resistance (attrition loss4%)

especially Si-13 with an attrition loss of 1.89%. Hematite appeared in XRD patterns when silica sol above 15 nm is used. TEM micrographs show that no obvious SiO

2

particles appear when silica sol particle with size less than 8 nm was used

but SiO

2

particles coated with small ferrihydrite particles appear when silica sol above 8 nm was used. Si-O-Si vibration peak in FT-IR spectra increases with increasing silica sol size. Samples prepared with silica sol show good stability of FT reactions

and the average molecular weight of FT products increases with the increase of SiO

2

particle.