Hydrogen Storage in Nanotubes

In their recent letter (28 Jan., p. [593][1]), Michael J. Heben and Anne C. Dillon point out that we, along with another group of authors, had misinterpreted their research with hydrogen storage in carbon single-wall nanotubes. In our report, “High H2 uptake by alkali-doped carbon nanotubes under ambient pressure and moderate temperatures” (P. Chen, W. Wu, J. Lin, K. L. Tan, 2 July 1999, p. 91), we referred to the work of A. C. Dillon et al. ([1][2]) as being performed at a temperature of 133 kelvin and a pressure of 300 torr. Although they noted that the rate of hydrogen desorption peaked between 275 and 300 kelvin, we emphasized that the adsorption started at 133 kelvin and 300 torr, because from our experience with multiwalled carbon nanotubes, we had found that such nanotubes adsorb only a small amount of H2 at ambient or high temperatures [our work is reported in ([2][3])]. Recently, we performed low-temperature, low-pressure experiments on multiwalled carbon nanotubes and found that there was only very little H2 staying in the sample at ambient or high temperatures in spite of the fact that adsorption was observed at subambient temperatures. This shows that some hydrogen was stabilized between 275 and 300 kelvin by Dillon et al. 's single-wall carbon nanotubes. We apologize for our misemphasizing the low-temperature and low-pressure conditions of Dillon et al. 's experiments, which may have led to a misunderstanding of their results as referred to in our report. 1. [↵][4]1. A. C. Dillon 2. et al. , Nature 386, 377 (1997). [OpenUrl][5][CrossRef][6][Web of Science][7] 2. [↵][8]1. X. Wu, 2. P. Chen, 3. J. Lin, 4. K. L. Tan , Int. J. Hydrogen Energy 25, 261 (2000). [OpenUrl][9][CrossRef][10][Web of Science][11] [1]: /lookup/doi/10.1126/science.287.5453.591e [2]: #ref-1 [3]: #ref-2 [4]: #xref-ref-1-1 View reference 1 in text [5]: {openurl}?query=rft.jtitle%253DNature%26rft.volume%253D386%26rft.spage%253D377%26rft_id%253Dinfo%253Adoi%252F10.1038%252F386377a0%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [6]: /lookup/external-ref?access_num=10.1038/386377a0&link_type=DOI [7]: /lookup/external-ref?access_num=A1997WQ17000058&link_type=ISI [8]: #xref-ref-2-1 View reference 2 in text [9]: {openurl}?query=rft.jtitle%253DInt.%2BJ.%2BHydrogen%2BEnergy%26rft.volume%253D25%26rft.spage%253D261%26rft.atitle%253DINT%2BJ%2BHYDROGEN%2BENERGY%26rft_id%253Dinfo%253Adoi%252F10.1016%252FS0360-3199%252899%252900037-3%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [10]: /lookup/external-ref?access_num=10.1016/S0360-3199(99)00037-3&link_type=DOI [11]: /lookup/external-ref?access_num=000084301900011&link_type=ISI