Hydrogen binding on the B36 borophene nanoflake decorated with first row transition metal atoms: DFT, QTAIM and AIMD study

Abstract

Borophene, a monolayer of boron atoms, belongs to intensively studied two-dimensional “beyond-graphene” materials. The B₃₆ borophene nanoflake is a finite size model system, containing a hexagonal vacancy similar to the ones present in β₁₂ and χ₃ borophene sheets. The hydrogen binding performance of B₃₆ decorated with various transition metal atoms is investigated using density functional theory and quantum theory of atoms in molecules. Hydrogen is considered to become one of the crucial energy sources in future, hence, a search for effective hydrogen storage materials is of urge importance. Obtained results suggest that B₃₆ decorated with Co, Ni, Fe, and Cu possess strong affinity to bind the H₂ molecule via formation of η²-dihydrogen bonds. Among them, the strongest H₂ binding is found for Co- and Ni-decorated B₃₆. Furthermore, B₃₆ decorated with Sc and Ti behave like H–H bond breakers while B₃₆ decorated with Zn possess only negligible affinity to bind H₂ molecule. The stability of the B₃₆ decorated with Co and Ni is verified by ab initio molecular dynamics. The presented data may also serve as a basis for reference in future large-scale computational studies of borophene-based materials.