A molecular dynamics investigation of hydrogen adsorption on Ag–Cu bimetallic nanoclusters supported on a bundle of single-walled carbon nanotubes

Abstract

The adsorption of H₂ on nanocomposites containing a bundle of single-walled carbon nanotubes and an Ag_250−nCu_n bimetallic nanocluster located on the groove site of the bundle, was studied by molecular dynamics simulation at temperatures of 300 to 500 K. Simulations were performed in order to study the effect of the Ag mole fraction and the diameter of the nanotube on the H₂ adsorption. The structure of the nanocluster obeys a core–shell character in which Ag atoms tend to segregate at its surface. The adsorption isotherms show Langmuir-type (I) behavior with monolayer regime at all of the mentioned temperatures and Ag mole fractions. An increase of the Ag mole fraction increases the H₂ adsorption and an increase of the diameter of the nanotube decreases the adsorption. Therefore, the Ag mole fraction and nanotube diameter act in opposite directions. However, the effect of the Ag mole fraction is more important than the diameter of the nanotube in the bundle, which is favorable from an experimental point of view.