Hydrogen storage properties of a Ru-decorated carbon nanomaterial

VALERIA VERDINELLI; ESTEFANIA GERMAN; ALFREDO JUAN

Dubrovnik

Conferencia; 29th International Conference on Diamond and Carbon Materials; 2018

Elsevier

An alternative fuel is needed for the future energy demand when fossil fuels become unavailable. Among potential candidates such as solar, wind, nuclear, tidal, hydro, biofuels and geothermal energy, hydrogen appears to be the best choice due to its high density per unit mass, no environmental implications and abundance in the universe. However, hydrogen utilization as fuel is being hindered by lack of effective hydrogen storage solutions. Although carbon nanomaterials are promising hydrogen storage media, a modification of their surfaces is required to increase the hydrogen uptake capacity. Ru decorated single-walled carbon nanotube (SWCNT) has been studied by using spin-polarized density functional theory (DFT). A Ru atom is adsorbed on SWCNT with an adsorption energy (Eads) of -2.15 eV. Bader charge analysis reveals a charge transfer of 0.44 e- from Ru atom to SWCNT. A hydrogen molecule interacts with Ru with an Eads (H2) = -0.70 eV, whereas the H-H bond elongates from 0.75 to 2.35 Å. The subsequent addition of H2 molecules on the previous system (H2-Ru/SWCNT) shows that Ru adatom can hold up to four H2 molecules presenting an Eads of -0.93 eV/H2. After H2 molecules adsorption, Ru atom is placed on the bridge site instead of being near the hollow site. These results suggest that Ru/SWCNT system can be a good candidate for hydrogen storage applications.