Graphite Nanofibers: Demineralization Procedure

Graphite nanofibers (GNF) have been utilized in a number of catalysis and alternative energy applications. For example, they have found use in Lithium-ion batteries where they have been found to be ideal for lithium intercalation,1 as well as in fuel cells where, combined with platinum nanoparticles, they serve as a cathode material.2 GNF can also be used as a catalyst support, enhancing the reactivity and selectivity of supported metal catalysts.3

As-prepared graphite platelet nanofibers can contain small metallic impurities resulting from the preparation procedure. These metallic impurities can interfere with the intended use, particularly when using the graphite nanofiber as a catalyst or catalyst support. By utilizing the acid wash procedure outlined here, the small metallic impurities can be removed, and an overall purity ca. 99.9% can be achieved.

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Demineralization Procedure

  1. Prepare a 1M aqueous solution of either HCl or HNO3

    - HNO3 improves the dispersion properties and is preferred when the materials are to be used as catalytic supports.

  2. Immerse the as-prepared graphite carbon nanofibers in solution prepared in step (a).
  3. Maintain constant agitation for 7-8 hours.
  4. Decant the liquid, which contains metal impurities.
  5. Repeat steps (a) – (d) four times.
  6. Wash the solid in de-ionized water until it is pH neutral.
  7. Dry the graphite nanofibers in an oven at 110°C for 24 hours.




  1. Yoon, S-H.; Park, C-W.; Yang, H.; Korai, Y.; Mochida, I.; Baker, R.T.K.; Rodriguez, N.M. Carbon, 2004, 42, 21.
  2. Bessel, C.A.; Laubernds, K.; Rodriguez, N.M.; Baker, R.T.K. J. Phys Chem. B. 2001, 105, 1115.
  3. Ma, J.; Park, C.; Rodriguez, N.M.; Baker, R.T.K. J. Phys. Chem. B. 2001, 105, 11994.

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