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

Document Type : Research Article


School of Chemistry, College of Science, University of Tehran, Tehran, I.R. IRAN


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.


Main Subjects

[1] Herman R., “Studies in Surface and Catalyst’’, (Chapter 7), Elsevier, Amsterdam, (1990). 
[2] Natta G., Colombo U., Pasquon I., “Catalysis”, Emmet P.H. (Ed.) Vol. 5, (1957).
[3] Morgan G.T., Hardy D.V.N., Procter R.A., Physics and Chemistry of Alkali Metal Adsorption, J. Soc. Chem. Ind. Trans., 1T, p. 56 (1932).
[4] Smith K.J., Anderson R.B., Alcohols Synthesis Using Modified Methanol Synthesis Catalysts, Canadian Journal of Chemistry Engineering, 61, p. 40 (1983).
[5] Smith K., Anderson R., Mechanism of Ethanol Formation, J. Catalysis, 85, p. 428 (1984).
[6] Quarderer Q.J., Cochram G.A., Catalytic Process for Producing Mixed Alcohols from Hydrogen and Carbon Monoxide, PCT Int. Pat. Publication No. WO84/03696 (1984).
[7] Kinkade N.E., Process for Producing Alcohols from Carbon Monoxide and Hydrogen Using an Alkali-Molybdenum Sulfide Catalyst, PCT Int. Pat. Publication No. WO 85/03073 (1985).
[8] Jackson G.R., Mahajan D., Method for Production of Mixed Alcohols from Synthesis Gas, U.S. Patent 6,248,796 (2001).
[9] Chaumette P., Courty P., Durand D., Grandvallet P., Travers C., Process for Synthesizing a Mixture of Primary Alcohols from a Synthesis Gas in the Presence of a Catalyst Containing Copper, Cobalt, Zinc, and Aluminum, GB Patent, 2,158,730 (1985).
[10] Woo H., Park K.Y., Mixed Alcohol Using Mo2C Catalysts, Appl. Catal., 75, p. 267 (1991). 
[11] Jiang M., Bian G.Z., Fu Y.L., The Structure of Oxidic and Sulfided Mo Catalysts Upported on AC Was Studied by Means of X-Ray Diffraction, Journal of Catalysis, 146, p. 144 (1994).
[12] Lee J.S., Kim S., Lee K.H., Nam I.S., Kim Y.G., Woo H.C., Effect of K-Mo Interaction in K-MoO3/ γ-Al2O3 on the Properties for AS from Syngas, Appl. Catal., 110, p. 11(1994).
[13] Tatsumi T., Muramatsu A., Tominga H., Mechanistic Study on the AS Over Mo Catalysts: Addition of Probe Molecules to CO-H2, Journal of Catalysis, 115, p. 388 (1989).
[14] Iranmahboob J., Toghiani H., Hill D., Dispersion of Alkali on the Surface of Co-MoS2: A Comparison of K and Cs as a Promoter for HAS, Appl. Catal., 247, p. 207 (2003).
[15] Iranmahboob J., Hill D.O., Alcohol Synthesis from Syngas over  K2CO3/CoS/MoS2 on Activated Carbon, Catalysis Letters, 78(4) p. 49 (2002).
[16] Surisetty V., Tavasoli A., Dalai A., Synthesis of Higher Alcohols from Syngas over Alkali Promoted MoS2 Catalysts, App. Catal., 365, p. 43 (2009).
[17] Li Z., Fu Y.L., Bao J., Jiang M., Hu T.D., Liu T ., Xie Y.N., Effect of Cobalt Promoter on Co-Mo-K/C Catalysts Used for Mixed Alcohol Synthesis, Applied Catalysis, 220, p. 21(2001).
[18] van Berge P.J., van de Loosdrecht J., Barradas S., van der Kraan A.M., Oxidation of Cobalt Based F.T. Catalysts as a Deactivation Mechanism, Catalysis Today, 58, p. 321 (2000).
[19] Xiaoming M., Guodong L., Hongbin Z., Co-Mo-K Sulfide-Based Catalyst Promoted Bymulti-Walled CNTs for Higher Alcohol Synthesis, Chinese J.  Catal., 27, p. 1019 (2006).
[20] Santiesteban J., Bogdan C.E., Higher Alcohols Synthesis Using Mobased Catalysts, Proceedings of 9th ICC, 2, Calgary, Canada, p. 561 (1988).
[21] Surisetty V., Dalai A., Kozinski J., Intrinsic Reaction Kinetics of  HAS from Syngas over a Alkalized Co-Rh-Mo Catalyst Supported on MWCNTs, Energy Fuels, 24, p.4130 (2010).
[22] Surisetty V., Dalai A., Kozinski J., Influence of Porous Characteristics of the Support on Alkali-Modified Co-Rh-Mo Sulfided Catalysts for HAS, Appl. Catal, 393, p. 50 (2011).
[23] Surisetty V., Dalai A., Kozinski J., Effect of Rh on MWCNT-supported Alkali-modified MoS2 for HAS from CO Hydrogenation” Appl. Catal., 381, p. 282 (2010).