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Study on the induction period of methane aromatization over Mo/HZSM-5: partial reduction of Mo species and formation of carbonaceous deposit

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Abstract

The induction period of dehydrogenation and aromatization of methane over Mo/HZSM-5 was studied by combining a pulse reaction method with TPSR, UV laser Raman, and 13C CPMAS NMR techniques. BET and XRD results showed that Mo species were well dispersed on/in the zeolite. TPSR in CH4 stream revealed that Mo species were reduced in at least two different stages before the formation of benzene. TPR results were in agreement with TPSR results. The two stages might be attributed to the reduction of two kinds of Mo6+ species to low valence Mo species. One was polymolybdate MoO3, and the other was crystalline MoO3. UV Raman spectra showed the existence of octahedrally coordinated polymolybdate species. XRD, however, did not detect any crystalline MoO3, possibly because they were too small to be detected with this technique. Pulse reaction results indicated that pre-reduction of the catalyst and formation of carbonaceous deposit could shorten the induction period. It is concluded that the formation of active sites during the induction period via partial reduction of Mo6+ species and formation of carbonaceous deposit on partially reduced Mo species is of significance for methane aromatization over Mo/HZSM-5.

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References

  1. Y. Ono, Catal. Rev. Sci. Eng. 34 (1992) 179.

    CAS  Google Scholar 

  2. J.H. Lunsford, in: Proceedings 10th International Congress Catalysis, eds. L. Guczi, F. Solymosi and P. Tétényi (Akadémiai Kiadó, Budapest, 1993) p. 103.

    Google Scholar 

  3. V.R. Choudhary, A.K. Kinage and T.V. Choudhary, Science 275 (1997) 1286.

    Article  CAS  Google Scholar 

  4. Y. Xu, S. Liu, L. Wang, M. Xie and X. Guo, Catal. Lett. 30 (1995) 135.

    Article  Google Scholar 

  5. S.-T. Wong, Y. Xu, W. Liu, L. Wang and X. Guo, Appl. Catal. A 136 (1996) 7.

    Article  CAS  Google Scholar 

  6. Y. Xu, W. Liu, S.-T. Wong, L. Wang and X. Guo, Catal. Lett. 40 (1996) 207.

    Article  CAS  Google Scholar 

  7. L. Wang, Y. Xu, S.-T. Wong, W. Cui and X. Guo, Appl. Catal. A 152 (1997) 173.

    Article  CAS  Google Scholar 

  8. Y. Shu, Y. Xu, S.-T. Wong, L. Wang and X. Guo, J. Catal. 170 (1997) 11.

    Article  CAS  Google Scholar 

  9. L. Chen, L. Lin, Z. Xu, T. Zhang and X. Li, Catal. Lett. 39 (1996) 169.

    Article  CAS  Google Scholar 

  10. L. Chen, L. Lin, Z. Xu, X. Li and T. Zhang, J. Catal. 157 (1995) 190.

    Article  CAS  Google Scholar 

  11. D. Wang, J.H. Lunsford and M.P. Rosynek, Topics Catal. 3 (1996) 289.

    Article  CAS  Google Scholar 

  12. D. Wang, J.H. Lunsford and M.P. Rosynek, J. Catal. 169 (1997) 347.

    Article  CAS  Google Scholar 

  13. F. Solymosi, A. Erdöhelyi and A. Szöke, Catal. Lett. 32 (1995) 43.

    Article  CAS  Google Scholar 

  14. A. Szöke and F. Solymosi, Appl. Catal. A 142 (1996) 361.

    Article  Google Scholar 

  15. F. Solymosi, A. Szöke and J. Cserényi, Catal. Lett. 39 (1996) 157.

    Article  CAS  Google Scholar 

  16. F. Solymosi, J. Cserényi, A. Szöke, T. Bánsági and A. Oszkó, J. Catal. 165 (1997) 150.

    Article  CAS  Google Scholar 

  17. L. Wang, L. Tao, M. Xie, G. Xu, J. Huang and Y. Xu, Catal. Lett. 21 (1993) 35.

    Article  CAS  Google Scholar 

  18. J.R. Regalbuto and J.-W. Ha, Catal. Lett. 29 (1994) 189.

    Article  CAS  Google Scholar 

  19. C.C. Williams, J.G. Ekerdt, J.-M. Jehng, F.D. Hardcastle, A.M. Turek and I.E. Wachs, J. Phys. Chem. 95 (1991) 8781.

    Article  CAS  Google Scholar 

  20. C.C. Williams, J.G. Ekerdt, J.-M. Jehng, F.D. Hardcastle and I.E. Wachs, J. Phys. Chem. 95 (1991) 8791.

    Article  CAS  Google Scholar 

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Jiang, H., Wang, L., Cui, W. et al. Study on the induction period of methane aromatization over Mo/HZSM-5: partial reduction of Mo species and formation of carbonaceous deposit. Catalysis Letters 57, 95–102 (1999). https://doi.org/10.1023/A:1019087313679

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