Enhancement of MoO3–K2O/CNTs nanocatalyst activity and selectivity in higher alcohols synthesis using microemulsion technique

Alkalized MoS2 nanocatalysts supported on carbon nanotubes (CNTs) is prepared using microemultion technique with water-to-surfactant ratios of 1–4. The nanocatalysts were extensively characterized by different methods and their activity and selectivity in higher alcohols synthesis (HAS) 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 (15 wt.% Mo). The TEM images showed that small Mo nanoparticles are confined inside the CNTs and the on the outer surface of the CNTs (2–7 nm). Using microemultion technique with water to surfactant ratio of one; the average MoO3 particle sizes decreased to 4.5 nm, the %dispersion increased to 60.75 and the %reduction increased by 43%. Also, the chemical interactions between K–Mo–O species increased, enhancing the conditions for the formation of alcohols. Activity and selectivity were found to be dependent on the catalyst preparation method and water to surfactant ratio. The %CO conversion increased to 43.8%. The CNTs-supported MoO3–K2O nanocatalyst synthesized by the proposed microemulsion technique with water to surfactant ratio of one, decreased the hydrocarbons selectivity to 21.98% and increased the alcohols selectivity to 65.21%. Finally, using microemultion method dramatically decreased the methanol selectivity and increased ethanol and other higher alcohols selectivities.