Investigation of 2D Boridene from First Principles and Experiments
Journal article, 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

MBene

boridene

surface terminations

HER

Author

Pernilla Helmer

Linköping University

Joseph Halim

Linköping University

Jie Zhou

Linköping University

Roopathy Mohan

Chalmers, Physics, Chemical Physics

Björn Wickman

Chalmers, Physics, Chemical Physics

Jonas Bjork

Linköping University

Johanna Rosen

Linköping University

Advanced Functional Materials

1616-301X (ISSN) 16163028 (eISSN)

Vol. 32 2109060

Subject Categories

Materials Engineering

Physical Sciences

DOI

10.1002/adfm.202109060

More information

Latest update

7/17/2024