Calcium-Decorated Carbyne Networks as Hydrogen Storage Media

Abstract

Among the carbon allotropes, carbyne chains appear outstandingly accessible for sorption and very light. Hydrogen adsorption on calcium-decorated carbyne chain was studied using ab initio density functional calculations. The estimation of surface area of carbyne gives the value four times larger than that of graphene, which makes carbyne attractive as a storage scaffold medium. Furthermore, calculations show that a Ca-decorated carbyne can adsorb up to 6 H(2) molecules per Ca atom with a binding energy of ∼0.2 eV, desirable for reversible storage, and the hydrogen storage capacity can exceed ∼8 wt %. Unlike recently reported transition metal-decorated carbon nanostructures, which suffer from the metal clustering diminishing the storage capacity, the clustering of Ca atoms on carbyne is energetically unfavorable. Thermodynamics of adsorption of H(2) molecules on the Ca atom was also investigated using equilibrium grand partition function.

Carbon-atom wires: 1-D systems with tunable properties

“…176 A network of wires decorated by calcium atoms has been proposed as an efficient material for H storage, as a result of numerical calculations. 177 Possible architectures comprise a wire-graphene system and a 3-D network of wires joined by sp 3 links to form a diamond-like lattice.…”

Improved hydrogen storage in Ca-decorated boron heterofullerenes: a theoretical study

“…[7][8][9][10][11][12][13][14][15][16][17][18][19] In this work, we study the Ca decoration of carbon-boron heterofullerenes. The rst heterofullerenes realized in experiments were boron-doped carbon fullerenes.…”

Theoretical study of hydrogen adsorption on Ca-decorated C48B12 clusters

“…This binding mechanism has been confirmed in the Ca-coated systems reported previously. 18,29,32,34,42 C. Adsorption of molecular hydrogen on Ca-decorated C 48 B 12 To know the binding mode of H 2 molecules, they are allowed to approach the Ca atoms in different orientations. The adsorption strength of H 2 molecules is measured by the adsorption energy (E ad ) which is defined as…”

“…29 This makes Ca atom one of the most attractive decorating metal atoms. [30][31][32][33][34][35] On the other hand, it was suggested to enhance the structural stability of metal decorated complexes by introducing structural or chemical defects. [36][37][38][39][40][41][42] For instance, substitutional doping of boron at the carbon site in carbon nanomaterials improves dramatically the binding strength of metal atoms.…”