Effects of particle size on the activity and product selectivity of Fe-Mn/CNTs nano catalyst

Bimetallic Fe-Mn nano catalysts supported on carbon nanotubes (CNTs) are prepared using microemulsion technique with water-to-surfactant ratios of 0.4-1.6. The nano catalysts were extensively characterized by different methods and their activity and selectivity in Fischer– Tropsch synthesis (FTS) have been assessed in a fixed bed micro-reactor. The physico-chemical properties and performance of the nanocatalysts were compared with the catalyst prepared by impregnation method. Very narrow particle size distribution has been produced by the microemulsion technique at the relatively high loading of active metal. Using microemultion technique with water to surfactant ratio of 0.4 decreased the average iron particle sizes to 5.7 nm. The percentage reduction and percentage dispersion are almost doubled. Activity and selectivity were found to be dependent on iron average particle sizes. The CO% conversion and FTS rate increased from 58.6 to 70.98% and 0.2 to 0.289 (gr. HC/gr. cat./hr), respectively.While the WGS rate decreased from 0.08 to 0.056 (gr. CO2/gr. cat./hr) and olefins/paraffins ratio incresed from 0.9 to 2 .

Keywords:

Fischer-Tropsch synthesis , Iron , Magnesium , Microemulsion , particle size ,