eprintid: 10167826 rev_number: 7 eprint_status: archive userid: 699 dir: disk0/10/16/78/26 datestamp: 2023-04-05 16:03:58 lastmod: 2023-04-05 16:03:58 status_changed: 2023-04-05 16:03:58 type: article metadata_visibility: show sword_depositor: 699 creators_name: Al-Hamdani, Yasmine S creators_name: Zen, Andrea creators_name: Michaelides, Angelos creators_name: Alfè, Dario title: Mechanisms of adsorbing hydrogen gas on metal decorated graphene ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F57 divisions: F60 note: This is the published version of record. For information on re-use, please refer to the publisher’s terms and conditions. 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. date: 2023-03 date_type: published publisher: American Physical Society (APS) official_url: https://doi.org/10.1103/PhysRevMaterials.7.035402 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green article_type_text: Article verified: verified_manual elements_id: 2014097 doi: 10.1103/physrevmaterials.7.035402 lyricists_name: Michaelides, Angelos lyricists_name: Al-Hamdani, Yasmine lyricists_name: Zen, Andrea lyricists_name: Alfe, Dario lyricists_id: AMICH30 lyricists_id: YSALH17 lyricists_id: AZENX51 lyricists_id: DALFE65 actors_name: Flynn, Bernadette actors_id: BFFLY94 actors_role: owner full_text_status: public publication: Physical Review Materials volume: 7 number: 3 article_number: 035402 issn: 2475-9953 citation: Al-Hamdani, Yasmine S; Zen, Andrea; Michaelides, Angelos; Alfè, Dario; (2023) Mechanisms of adsorbing hydrogen gas on metal decorated graphene. Physical Review Materials , 7 (3) , Article 035402. 10.1103/physrevmaterials.7.035402 <https://doi.org/10.1103/physrevmaterials.7.035402>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10167826/1/PhysRevMaterials.7.035402.pdf