Investigation of 2D Boridene from First Principles and Experiments
Artikel i vetenskaplig tidskrift, 2022

Recently, a 2D metal boride - boridene - has been experimentally realized in the form of single-layer molybdenum boride sheets with ordered metal vacancies, through selective etching of the nanolaminated 3D parent borides (Mo2/3Y1/3)(2)AlB2 and (Mo2/3Sc1/3)(2)AlB2. The chemical formula of the boridene was suggested to be Mo4/3B2-xTz, where T-z denotes surface terminations. Here, the termination composition and material properties of Mo4/3B2-xTz from both theoretical and experimental perspectives are investigated. Termination sites are considered theoretically for termination species T = O, OH, and F, and the energetically favored termination configuration is identified at z = 2 for both single species terminations and binary termination mixes of different stoichiometries in ordered and disordered configurations. Mo4/3B2-xTz is shown to be dynamically stable for multiple termination stoichiometries, displaying semiconducting, semimetallic, or metallic behavior depending on how different terminations are combined. The approximate chemical formula of a freestanding film of boridene is attained as Mo1.33B1.9O0.3(OH)(1.5)F-0.7 from X-ray photoelectron spectroscopy (XPS) analysis which, within error margins, is consistent with the theoretical results. Finally, metallic and additive-free Mo4/3B2-xTz shows high catalytic performance for the hydrogen evolution reaction, with an onset potential of 0.15 V versus the reversible hydrogen electrode.

electronic structure



surface terminations



Pernilla Helmer

Linköpings universitet

Joseph Halim

Linköpings universitet

Jie Zhou

Linköpings universitet

Roopathy Mohan

Chalmers, Fysik, Kemisk fysik

Björn Wickman

Chalmers, Fysik, Kemisk fysik

Jonas Bjork

Linköpings universitet

Johanna Rosen

Linköpings universitet

Advanced Functional Materials

1616-301X (ISSN) 16163028 (eISSN)

Vol. 32 2109060






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