DFT study of H2 adsorption on Pd-decorated single walled carbon nanotubes with C-vacancies

Carbon nanotubes are considered important materials for hydrogen storage. Although the C–H interaction is very weak at room temperature, the incorporation of highly dispersed Pd nanoparticles increases the H2 adsorption on carbon surfaces. In this work we performed density functional theory studies of H2 adsorption on single walled carbon nanotubes (SWCNTs) with C-vacancies and a Pd decoration. We used the VASP and SIESTA codes. Our calculations show that Pd adsorption is favored on the C-vacancies of the (5,5) SWCNT, while H2 adsorption also occurs preferentially on C-defective sites.

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► Pd adsorption is favored on C-vacancies of the (5,5) SWCNT system.
► H2 adsorption occurs preferentially on C-defective sites and then on Pd decoration.
► Pd blocks the preferential interaction between C-vacancies and H2.
► Decoration promotes H2 adsorption on Pd and facilitates subsequent desorption.