@article{discovery10167826,
           month = {March},
          volume = {7},
          number = {3},
       publisher = {American Physical Society (APS)},
            note = {This is the published version of record. For information on re-use, please refer to the publisher's terms and conditions.},
           title = {Mechanisms of adsorbing hydrogen gas on metal decorated graphene},
         journal = {Physical Review Materials},
            year = {2023},
             url = {https://doi.org/10.1103/PhysRevMaterials.7.035402},
            issn = {2475-9953},
          author = {Al-Hamdani, Yasmine S and Zen, Andrea and Michaelides, Angelos and Alf{\`e}, Dario},
        abstract = {Hydrogen is a key player in global strategies to reduce greenhouse gas emissions. In order to make hydrogen
a widely used fuel, we require more efficient methods of storing it than the current standard of pressurized
cylinders. An alternative method is to adsorb H2 in a material and avoid the use of high pressures. Among many
potential materials, layered materials such as graphene present a practical advantage as they are lightweight.
However, graphene and other 2D materials typically bind H2 too weakly to store it at the typical operating
conditions of a hydrogen fuel cell, meaning that high pressure would still be required. Modifying the material,
for example by decorating graphene with adatoms, can strengthen the adsorption energy of H2 molecules, but
the underlying mechanisms are still not well understood. In this work, we systematically screen alkali and
alkaline-earth metal decorated graphene sheets for the static thermodynamic adsorption of hydrogen gas from
first principles and focus on the mechanisms of binding. We show that there are three mechanisms of adsorption
on metal decorated graphene and each leads to distinctly different hydrogen adsorption structures. The three
mechanisms can be described as weak van der Waals physisorption, metal adatom facilitated polarization, and
Kubas adsorption. Among these mechanisms, we find that Kubas adsorption is easily perturbed by an external
electric field, providing a way to tune H2 adsorption. This work is foundational and builds our understanding of
H2 adsorption under idealized conditions.}
}