Molybdenum Loading Effects on the Physico-Chemical Properties and Performance of Carbon Nanotubes Supported Alkalized MoS2 Catalysts for Higher Alcohols Synthesis

An extensive study of Higher Alcohols Synthesis (HAS) from syngas using alkalized MoS2 catalysts supported on Carbon Nanotubes (CNTs) is reported. Up to 30wt.% of Mo and 8wt.% K are added to the CNTs by impregnation method. The catalysts were characterized by different methods and the performance of the catalysts was assessed in a micro-reactor. TEM images showed that most of the metal particles were homogeneously distributed inside the tubes and the rest on the outer surface of the CNTs, with particle sizes in the range of 3 to 16 nm. Temperature Programmed Reduction (TPR) tests showed that increasing the amount of Mo decreased the first TPR peak from 518 to 503oC and increased the second TPR peak temperature from 782 to 825oC.  The diffraction peaks representing the characteristic K-Mo-O phase (these species can enhance formation of higher alcohols) were observed in the XRD of catalysts. The catalyst with 20 wt.% Mo and 8 wt.% K showed the highest conversion. The total alcohol selectivity reached a maximum of 45.3 wt.%        on the catalyst with 15 wt.% Mo. The catalyst with 15 wt.% Mo exhibited selectivity of 35.3 wt.% towards higher alcohols.