Surfactant-Assisted Restructuring of Boron to Borophene: Implications for Enhanced Hydrogen Evolution

Abstract

Borophene 2D nanosheets of boron and the evolving group III trans-graphene are a potential material for a plethora of applications; however, they have not been well explored due to the ambiguity in their electronic configuration and consequent polymorphism. Here, we introduced liquid-phase treatments utilizing surfactants exfoliating boron to 2D borophene. Poly(ethelyene glycol) (PEG) polymeric chains with neutral characteristics simultaneously with surfactants of cationic and anionic characteristics, respectively, as cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) were utilized to constructively engineer a β rhombohedral crystal structure in borophene layers. These engineered borophene layers, on further analyzing their electrochemical performance by hydrogen evolution reactions, showed a heightened efficacy for borophene sheets synthesized in the presence of PEG, characterized by a Tafel slope of 178 mV/dec in a 0.5 M H2SO4 solution. This enhanced performance was intricately linked to the elevated quality of the borophene sheets during PEG-assisted liquid-phase treatment and to the increased accessibility of active sites characterized by the β rhombohedral crystal lattices engineered by PEG polymeric chains.