Synthesis, Characterization, and First-Principles Analysis of the MAB-Like Ternary Transition-Metal Boride Fe(MoB)₂

Abstract

Novel transition-metal borides have attracted considerable attention because they exhibit high stability under extreme conditions. Compared with binary borides, ternary transition-metal borides (TTMBs) exhibit novel boron substructures and diverse properties, which result in excellent designability. In this study, we synthesized the MAB-like (where M = iron, A = molybdenum, and B = boron) phase Fe(MoB) 2 using a high-pressure and high-temperature method. Fe(MoB) 2 exhibited ferromagnetic metastable characteristics with a saturation magnetization of 8.35 emu/g at room temperature. Microhardness measurement revealed an indentation hardness of 10.72 GPa, which was higher than those of conventional magnetic materials. First-principles calculations revealed excellent mechanical properties, which mainly originated from the strong covalent short B 2 chains. Furthermore, magnetism was attributed to the Fe 3d electrons. Numerous d−d hybridizations existed between the Fe 3d e g and Mo 4d orbitals, and the antibonding/nonbonding state difference for up/down-spin electrons in the hybridization orbitals led to the local magnetic moment of Fe(MoB) 2 . The magnetic anisotropy energy analyses reveal that Fe(MoB) 2 prefers the easy magnetization axis along the z direction, and Mo atom acts as a medium to realize the exchange action between two Fe atoms. The B−B and Fe−B bonds were considerably stronger than the Fe−Mo and Mo−B bonds, and Fe(MoB) 2 exhibited a class of atomically laminate composed of FeB 2 and Mo layers. These results may provide guidance for the design of novel multifunctional TTMBs by adjusting the interactions between binary metal components.

Increasing Mo5+ in M-doped La2(MoO4)3 (M = Fe, Co, Ni, Cu, and Zn) toward efficient electrocatalytic nitrogen fixation

“…37,38 Consequently, This journal is © The Royal Society of Chemistry 2024 a trend can be summarized that the higher percentage of Mo 5+ promotes the NRR performance due to facilitating the surface hydrogenation reaction and inhibiting the hydrogen precipitation reaction. [39][40][41] This trend is evidenced by the linear tting relationship between the Mo 5+ proportion, NH 3 yield rate, and FE (Fig. 3(f)).…”

Synthesis of Ni–B Compounds by High-Pressure and High-Temperature Method

“…And it is easy to find the growth step in microsize particles, and the B also have three forms of small ball-like B, dispersive B, and agminated B in the samples (Figures S4–S7). So, the Ni 2 B, α-Ni 4 B 3 , β-Ni 4 B 3 , and NiB are synthesized, even though a bit of boron in the samples, but it will not dramatically influence the properties of samples, ,, because the major form of B is small ball-like B, which is at local position and will influence the local properties. If the major form of B is dispersive B, it will exhibit distinct properties.…”

“…synthesized, even though a bit of boron in the samples, but it will not dramatically influence the properties of samples, 25,44,45 because the major form of B is small ball-like B, which is at local position and will influence the local properties. If the major form of B is dispersive B, it will exhibit distinct properties.…”

Tantalum Diboride: The Superhard and Metallic Boride

“…Transition-metal (TM) borides have been attracting considerable interest in recent years for their potential applications in extreme environments. − They are considered as good candidate materials for the main components of hypersonic vehicles and scramjet engines due to their good thermal conductivity, high melting point, high hardness, and so forth. The possible origins of these superior properties are due to the fact that the chemical bonds in these borides are extremely complicated with localized nonmetal-to-nonmetal, metal-to-nonmetal, or metal-to-metal interactions resembling both covalent and metallic bonds.…”