Microwave Doping of Sulfur and Iron in β₁₂ Borophene

Borophene, a 2D material exhibiting unique crystallographic phases like the anisotropic atomic lattices of β₁₂ and X₃ phases, has attracted considerable attention due to its intriguing Dirac nature and metallic attributes. Despite surpassing graphene in electronic mobility, borophene's potential in energy storage and catalysis remains untapped due to its inherent electrochemical and catalytic limitations. Elemental doping emerges as a promising strategy to introduce charge carriers, enabling localized electrochemical and catalytic functionalities. However, effective doping of borophene has been a complex and underexplored challenge. Here, an innovative, one-pot microwave-assisted doping method, tailored for the β₁₂ phase of borophene is introduced. By subjecting dispersed β₁₂ borophene in dimethylformamide to controlled microwave exposure with sulfur powder and FeCl₃ as doping precursors, S- and Fe doping in borophene can be controlled. Employing advanced techniques including high-resolution transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, confirm successful sulfur and iron dopant incorporation onto β₁₂ borophene is confirmed, achieving doping levels of up to 11 % and 13 %, respectively. Remarkably, S- and Fe-doped borophene exhibit exceptional supercapacitive behavior, with specific capacitances of 202 and 120 F g^-1, respectively, at a moderate current density of 0.25 A g^-1.