Borophene, a two-dimensional monolayer made of boron atoms, has attracted wide attention due to its appealing properties. Great efforts have been devoted to fine tuning its electronic and magnetic properties for desired applications. Herein, we theoretically investigate the versatile electronic and magnetic properties of bilayer borophene (BLB) intercalated by 3d transition metal (TM) atoms, TM@BLBs (TM = Ti-Fe), using ab initio calculations. Four allotropes of AA-stacking (α -, β-, β- and χ -) BLBs with different intercalation concentrations of TM atoms are considered. Our results show that the TM atoms are strongly bonded to the borophene layers with fairly large binding energies, around 6.31 ∼ 15.44 eV per TM atom. The BLBs with Cr and Mn intercalation have robust ferromagnetism, while for the systems decorated with Fe atoms, fruitful magnetic properties, such as nonmagnetic, ferromagnetic or antiferromagnetic, are identified. In particular, the α- and β-BLBs intercalated by Mn or Fe atom can be transformed into a semiconductor, half metal or graphene-like semimetal. Moreover, some heavily doped TM@BLBs expose high Curie temperatures above room temperature. The attractive properties of TM@BLBs entail an efficient way to modulate the electronic and magnetic properties of borophene sheets for advanced applications.

The structural, electronic, and magnetic properties of transition metal atoms intercalated bilayer graphene, [GTMG] x/y , (x, y is integer, TM = Ti, Cr, Mn, Fe) with different TM/carbon hexagons ratios and insertion patterns, are systematically studied by density functional theory calculations. All the studied systems are thermodynamically stable and competitive ionic−covalent bonding characters are dominated in the TM−graphene interaction. Most studied systems are ferromagnetic; particularly, [GCrG] 1:1 8 , [GCrG] 1:9 , [GFeG] 1:6(1) , and [GTMG] 1:6(2) (TM = Cr, Mn, Fe) exhibit large magnetic moment of 4. 43, 5.60, 7.02, 10.85, 9.04, and 5.19 μ B per unit cell, respectively. In contrast, [GCrG] 1:8 and [GFeG] 1:8 are ferrimagnetic, while eight other [GTMG] x/y are nonmagnetic. Moreover, five intercalation nanostructures of [GTMG] 1:18 (TM = Ti, Mn), [GTMG] 1:9 (TM = Ti, Mn) and [GTiG] 1:6 are semiconductors with the gaps of 0.141/0.824 eV, 0.413/0.668 eV, and 0.087 eV, respectively. Comparison on different isomers with same TM/carbon hexagons ratios showed that the electronic and magnetic properties of these [GTMG] x/y are largely dependent on the TM atoms arrangement. For thus, an effective way to control the electronic and magnetic properties of graphene based nanostructures is proposed.

Single atom catalysts (SAC) for water splitting hold the promise of producing H2 in a highly efficient and economical way. As the performance of SACs depends on the interaction between the adsorbate atom and supporting substrate, developing more efficient SACs with suitable substrates is of significance. In this work, inspired by the successful fabrications of borophene in experiments, we systematically study the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) activities of a series of 3d transition metal‐based SACs supported by various borophene monolayers (BMs=α_sheet, α1_sheet, and β1_sheet borophene), TM/BMs, using density functional theory calculations and kinetic simulations. All of the TM/BMs systems exhibit superior HER performance compared to Pt with close to zero thermoneutral Gibbs free energy (ΔGH*) of H adsorption. Furthermore, three Ni‐deposited systems, namely, Ni/α_BM, Ni/α1_BM and Ni/β1_BM, were identified to be superior OER catalysts with remarkably reduced overpotentials. Based on these results, Ni/BMs can be expected to serve as stunning bifunctional electrocatalysts for water splitting. This work provides a guideline for developing efficient bifunctional electrocatalysts.

Interlayer charge transfer in heterostructures plays an important role in tuning the electronic properties, which opens a new avenue for potential applications of two-dimensional nanomaterials. In this work, the hydrogen evolution...

Controlling the electronic and magnetic properties of G/TMD (graphene on transition metal dichalcogenide) heterostructures is essential to develop electronic devices. Despite extensive studies in perfecting G/TMDs, most products have various defects due to the limitations of the fabrication techniques, and research investigating the performances of defective G/TMDs is scarce. Here, we conduct a comprehensive study of the effects of 3d transition metal (TM ¼ Sc-Ni) atom-intercalated G/ WSe 2 heterostructures, as well as their defective configurations having single vacancies on graphene or WSe 2 sublayers. Interestingly, Ni-intercalated G/WSe 2 exhibits a small band gap of 0.06 eV, a typical characteristic of nonmagnetic semiconductors. With the presence of one single vacancy in graphene, nonmagnetic (or ferromagnetic) semiconductors with sizable band gaps, 0.10-0.51 eV, can be achieved by intercalating Ti, Cr, Fe and Ni atoms into the heterostructures. Moreover, V and Mn doped nondefective and Sc, V, Co doped defective G/WSe 2 can lead to sizable half metallic band gaps of 0.1-0.58 eV. Further analysis indicates that the significant electron transfer from TM atoms to graphene accounts for the opening of a large band gap. Our results provide theoretical guidance to future applications of G/TMD based heterostructures in (spin) electronic devices.