First principles study on desorption of chemisorbed hydrogen atoms from single-walled carbon nanotubes under external electric field

Based on first principles calculations, we suggest a new way to release chemisorbed hydrogen atoms from the single-walled carbon nanotubes. The transverse external electric field serves as the key source for this mechanism. As the electric field strength increases, there is a notable increase in the C–H bond lengths at the sharp highly curved sites of the carbon nanotube. The compression of the tube along the direction of electric field results in the release of hydrogen atoms from the sharp sites. The synergetic action of electric field and compression turns out the desorption process easier at favorable field strengths. This present investigation provides a new alternative way to release hydrogen atoms from the hydrogenated carbon nanotubes under the influence of external electric field that requires comparatively lower temperature suitable for hydrogen based fuel cells used in mobile applications.

► Desorption of chemisorbed hydrogen from hydrogenated SWCNTs under transverse electric field. ► Electric field weakens C–H bonds due to polarization of charges. ► Compression of the whole system under favorable field strength releases the hydrogen atoms. ► This mechanism may need relatively lower temperature than thermal desorption process (<600 K). ► With suitable SWCNTs, nanoindenter and electric field, desorption can be viable experimentally.