(165g) Study of Hydrogen Adsorption Behavior in Ti Doped B40 Fullerene

Hydrogen is considered as one of the most promising energy carrier due to its abundance, renewability, environmental friendliness and high energy density per unit mass. For commercial applications, it is necessary to develop safe and efficient high capacity hydrogen storage medium. Metal doping has been found to be an effective method to improve hydrogen adsorption ability. Boron is lighter than carbon and possess high electron binding energy than carbon which makes boron efficient for fullerene formation. B₄₀ fullerene has been considered as promising hydrogen storage material due to its large surface area. In this study we have investigated hydrogen adsorption behavior in B₄₀ fullerene doped with titanium (Ti) using density functional theory. The binding energy study of Ti doped both endohedrally and exohedrally in B₄₀ fullerene at the hexagonal and heptagonal cavities reveals that the doping of Ti atoms outside the hollow sites of the B₄₀ structure is most stable. A comparison study with different metal atoms doped at both hexagonal and heptagonal surface of B₄₀ nano cage shows that Ti₆B₄₀ exhibits good adsorption property with hydrogen due to its less cohesive energy than the binding energy with B₄₀. It is observed that the shape and stability of the B₄₀ cage structure rapidly changes with increased number of doping atoms. We have achieved a gravimetric density of 9.3 wt% when 36 H2 molecules are adsorbed. In addition, ab initio molecular dynamics simulations have shown the chemisorption and physisorption mechanisms of the hydrogen adsorption behavior