Modified ψ-Graphene as a hydrogen storage device in hydrogen-powered vehicles

What is it about?

Hydrogen-powered vehicles can become a reality if we solve some of the fundamental issues of hydrogen storage. Light vehicles cannot store large and cumbersome tanks containing pressurized hydrogen. We have theoretically predicted the possibility of hydrogen storage in yttrium-decorated ψ-Graphene using density functional theory simulations. This system can store more than the prescribed amount of hydrogen, is thermally stable, and shows reversible hydrogen storage—so that you can use and reuse the fuel tank.

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Photo by Eelco Böhtlingk on Unsplash

Photo by Eelco Böhtlingk on Unsplash

Why is it important?

Finding a solution to the hydrogen storage problem is imperative as the energy and fuel crises unfold. To this end, the solid-state hydrogen storage via adsorption on porous materials is a viable technique. Computational investigations are extremely useful as a screening tool—to figure out which materials can be applied and how they can be tuned to improve their storage performance. They also give insight into the underlying mechanisms of molecular-interactions during hydrogen adsorption. Through our simulations, we find that yttrium-decorated ψ-Graphene can store 8.31 wt% of hydrogen. The binding energy (−0.39 eV/hydrogen) is neither too weak nor too strong, and desorption can be initiated by raising the temperatures to ~497 K. The interaction between hydrogen molecules and the modified ψ-Graphene may be via the Kubas mechanism—which involves a donation and subsequent back-donation of electronic charge between the valence orbitals of yttrium and hydrogen. Further, the system is stable at elevated temperatures. Thus, theoretically speaking, yttrium-decorated ψ-Graphene is a promising hydrogen storage material. We hope this work motivates experimental trials.

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