First-principles prediction of two-dimensional B3Ox (x=1, 2) with bilayer boron kagome lattice

The kagome lattice has emerged as a novel platform for exploring multiple quantum states, and the design of new kagome lattice materials is instrumental in deepening research in this field. Recently, Gao et al. (Adv. Sci. 2023, 2305059) theoretically predicted a novel bilayer kagome borophene (BK-borophene) with multiple van Hove singularities. However, the weak antioxidant properties of this borophene hinder its practical applications. In this work, we have designed two novel boron oxides, B3O and B3O2, based on BK-borophene using first-principles calculations combined with surface oxidation strategies. Compared to BK-borophene, the newly designed B3O and B3O2 exhibit excellent antioxidant properties without compromising the bilayer kagome lattice structure composed of boron. Unlike the metallic BK-borophene, both boron oxides are semiconductors. In addition, we investigate the evolution of kagome energy bands in B3O and B3O2 using DFT and tight-binding models, providing a theoretical foundation for future related applications.