Characterization of Alumina and Silica Sol-Gel Encapsulated Fe/Co/Ru Nanocatalysts in Microchannel Reactors for F-T Synthesis of Higher Alkanes

Abstract

We have been investigating conversion of syngas (CO: H2) to higher alkanes [Fischer-Tropsch (F-T) Process] in 5 μm and 25 μm channel microreactors coated with sol-gel encapsulated Fe/Co-nanocatalysts. These nano-metal-catalysts were incorporated into the sol-gel matrix by two methods: 1) metal nitrate solutions; 2) metal oxide nanoparticles. Characterization of these catalysts containing Co and Fe in alumina and silica sol-gel has been carried out by several techniques. The surface area measurements by BET method show an average specific surface area of 285 m2/g for alumina and 300 m2/g for silica sol-gel encapsulated catalysts. In order to optimize the sol-gel preparation and deposition in the microchannels, the elemental composition of sol-gel encapsulated catalyst was examined by EDX. The SEM and AFM images of the reactors before and after deposition of the catalysts have also been studied. Hydrogenation-reduction efficiency of the activated Fe-Co catalysts and the level of poisoning after the reaction were estimated using a vibrating sample magnetometer (VSM). The result suggests more efficient reduction in the case of the nano-particle metal oxides compared to that derived from metal nitrate solutions. In overall, 85% of the catalyst is poisoned after 25 hrs of catalytic reaction. The surface area and the syngas conversion results indicate that silica sol-gel matrix may be a better catalyst support. For alumina sol-gel support, higher conversion of syn-gas is observed with 25 μm microreactor channels. For silica sol-gel, syngas conversion as high as 73% has been achieved by adding Ru as a promoter to the Fe/Co catalyst mixture.

This is a preview of subscription content, access via your institution.

References

  1. 1.

    C& EN, 18–19, July 21, 2003.

  2. 2.

    D. Schanke, A.M. Hilmen, E. Bergene, K. Kinnari, E. Rytter, E. Adnanes, A. Holmen.; Energy Fuel 10, 867 (1996).

    CAS  Article  Google Scholar 

  3. 3.

    S. Sun, N. Tsubaki and K. Fujimoto.; Applied Catalysis A: General 202, 121–131 (2000).

    CAS  Article  Google Scholar 

  4. 4.

    E. Iglesia; Applied Catalysis A: General 161, 59 (1997).

    CAS  Article  Google Scholar 

  5. 5.

    M.K. Niemela, A. Krause, T. Vaara, J. Kiviaho, M. Reinikainen.; Applied Catalysis A: General 147, 325 (1996).

    Article  Google Scholar 

  6. 6.

    R. Srinivasan et al.; AIChE Journal 43(11), 3059–3068 (1997).

    CAS  Article  Google Scholar 

  7. 7.

    W Ehrfeld, V Hessel, H Lowe; Microreactors: New Technology for Modern Chemistry, WILEY-VCH, Weinheim, ISBN3-527-29590-9, (2000).

    Google Scholar 

  8. 8.

    L. Zhang, D. Xue.; Journal of Material Science Letters 21, 1931–1933 (2002).

    CAS  Article  Google Scholar 

  9. 9.

    M Madou; Fundamentals of Microfabrication: The Science of Miniaturization, Second Edition CRC Press, ISBN 0-8493-9451-1, (1997).

    Google Scholar 

  10. 10.

    V. S. Nagineni et al.; Submitted to Chem. Mater.

  11. 11.

    S Zhao, PhD Dissertation, Louisiana Tech University, 2003.

  12. 12.

    K. Haas-Santo, M. Fichtner, K. Schubert, Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe, Germany.

  13. 13.

    Z Wang and Y. S. Lin.; Journal of Catalysis 174, 43–51 (1998).

    CAS  Article  Google Scholar 

  14. 14.

    S.V. Naidu, U. Siriwardane, A.N. Murty, N.S. Vegesna, J. Nwizugbu, J. Leonard, and C.R. Jones.; Microsc. Microanal. 9, 408, (2003).

    Article  Google Scholar 

Download references

Acknowledgments

We thank NSF EPSCoR for financial support of this work. We also thank Dr. K. Varahramyan and Mr. R. Aithal for their suggestions and help in this project.

Author information

Affiliations

Authors

Corresponding author

Correspondence to D. Kuila.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Kuila, D., Nagineni, V., Zhao, S. et al. Characterization of Alumina and Silica Sol-Gel Encapsulated Fe/Co/Ru Nanocatalysts in Microchannel Reactors for F-T Synthesis of Higher Alkanes. MRS Online Proceedings Library 820, 73–78 (2004). https://doi.org/10.1557/PROC-820-O3.4

Download citation