Fe Bond Research Articles

Metal-organophosphate biphasic interfacial coordination reaction synthesizing nanofiltration membranes with the ultrathin selective layer, excellent acid-resistance and antifouling performance

Phytate as a natural strongly charged organophosphate has recently attracted much attention in diverse fields including membrane separations towards water-energy-food nexus. However, the ideal phytate-based nanofiltration membrane with defect-free and ultrathin selective layer for highly-efficient water treatment is still much challengeable due to the typical aggregation of metal ions and uncontrolled reaction between metal ion and organophosphate via conventional coating method. Herein, metal-organophosphate biphasic interfacial coordination reaction is proposed to construct ultrathin (13.4 nm) selective layer of phytate-based nanofiltration membranes with high permeance and excellent stability by controllable coordination assembly. Iron acetylacetonate (Fe(acac)3) as an organic phase monomer with powerful electron-gaining ability is exploited to avoid the aggregation of traditional Fe(III) in aqueous phase, which can also coordinate with phytic acid (PA) to ensure a defect-free ultra-thin selective layer. The architecture of the phytate-based selective layer can be well regulated by optimizing the coordination metal source, the concentration of PA and Fe(acac)3, reaction time, so as to achieve the ultrahigh permeation flux of 190 L m−2 h−1 with excellent dye rejection (99.6%). Most interestingly, our phytate-based nanofiltration membranes with plenty of hydrophilic phosphate groups on the surface and high binding energy of P–O–Fe bond (−315.1 kJ mol−1) exhibited the long-term separation stability, excellent acid-resistance and anti-pollution ability, realizing the stable membrane separation process under harsh conditions.

Selective hydroboration of terminal alkynes catalyzed by heterometallic clusters with uranium–metal triple bonds

Selective hydroboration of terminal alkynes catalyzed by heterometallic clusters with uranium–metal triple bonds

Effects of Cu and Fe on cohesion and brittleness of grain boundary of tungsten

First principles calculation is performed to comparatively investigate the effects of Cu and Fe on energetics, cohesion properties, elastic properties, and fracture toughness of the ∑5(310)[001] grain boundary (GB) in body-centered cubic (BCC) W. It shows that both Cu and Fe have a tendency to segregate towards GB of BCC W and increase stability of GB with a lower GB energy. Calculations also indicate that Cu and Fe have a significant effect on decreasing the cohesion and increasing the brittleness of BCC W, which should be fundamentally attributed to lower bond energies of W–Cu and W–Fe bonds than the W–W bonds. The obtained results are interpreted and understood by bond energies and electronic structures, are consistent with existing experimental and theoretical observations, and would clarify the controversy about the effects of Cu and Fe on cohesion properties and brittleness of BCC W in the literature.

FeOx@graphitic carbon core–shell embedded in microporous N-doped biochar activated peroxydisulfate for removal of Bisphenol A: Multiple active sites induced non-radical/radical mechanism

The development of novel carbocatalysts with high activity and stability is important for the rapid degradation of emerging pollutants. Fe/N co-doped biochar (FeOx@GC-NBC) was innovatively synthesized with a pyrolytic carbonization method and then used as a functional peroxydisulfate (PDS) activator to degrade Bisphenol A (BPA). FeOx@GC-NBC with an optimized Fe/N ratio modification exhibited 23.16 and 8.65-fold great activity for BPA removal compared to pristine BC and N-doped BC, respectively. Approximately 93% of total organic carbon (TOC) could be removed in the heterogeneous activation system. We attributed theexcellent performance of FeOx@GC-NBC to the following attributes: i) a microporous carbon matrix with larger specific surface area (1691.81 m2·g−1) was favorable for adsorption, exposure of catalyst active sites (e.g., Fe-Nx, Graphitic N) and electron-transfer; ii) the C–O–Fe bond and highly core–shell structure of graphitic nanosheets (FeOx@GC) enhanced the N retention ability and durability of the catalyst; iii) organics adsorption dominated by a “pore-filling and π-π interaction” mechanism effectively promoted BPA oxidation. In acidic and neutral solutions, the radical oxidation (SO4•–and •OH) processes were responsible for BPA decomposition. In alkaline solution, electron transfer, instead of 1O2 or a high-valent iron species, was the dominant pathway. This study proposes a simple and feasible strategy to synthesize the FeOx@GC-NBC catalyst, which provides insights into catalyst design and the internal active sites involved in the purification mechanism of refractory organics.

Unveiling a Chemisorbed Crystallographically Heterogeneous Graphene/L10-FePd Interface with a Robust and Perpendicular Orbital Moment.

A crystallographically heterogeneous interface was fabricated by growing hexagonal graphene (Gr) using chemical vapor deposition (CVD) on a tetragonal FePd epitaxial film grown by magnetron sputtering. FePd was alternately arranged with Fe and Pd in the vertical direction, and the outermost surface atom was identified primarily as Fe rather than Pd. This means that FePd has a high degree of L10-ordering, and the outermost Fe bonds to the carbon of Gr at the interface. When Gr is grown by CVD, the crystal orientation of hexagonal Gr toward tetragonal L10-FePd selects an energetically stable structure based on the van der Waals (vdW) force. The atomic relationship of Gr/L10-FePd, which is an energetically stable interface, was unveiled theoretically and experimentally. The Gr armchair axis was parallel to FePd [100]L10, where Gr was under a small strain by chemical bonding. Focusing on the interatomic distance between the Gr and FePd layers, the distance was theoretically and experimentally determined to be approximately 0.2 nm. This shorter distance (≈0.2 nm) can be explained by the chemisorption-type vdW force of strong orbital hybridization, rather than the longer distance (≈0.38 nm) of the physisorption-type vdW force. Notably, depth-resolved X-ray magnetic circular dichroism analyses revealed that the orbital magnetic moment (Ml) of Fe in FePd emerged at the Gr/FePd interface (@inner FePd: Ml = 0.16 μB → @Gr/FePd interface: Ml = 0.32 μB). This interfacially enhanced Ml showed obvious anisotropy in the perpendicular direction, which contributed to interfacial perpendicular magnetic anisotropy (IPMA). Moreover, the interfacially enhanced Ml and interfacially enhanced electron density exhibited robustness. It is considered that the shortening of the interatomic distance produces a robust high electron density at the interface, resulting in a chemisorption-type vdW force and orbital hybridization. Eventually, the robust interfacial anisotropic Ml emerged at the crystallographically heterogeneous Gr/L10-FePd interface. From a practical viewpoint, IPMA is useful because it can be incorporated into the large bulk perpendicular magnetic anisotropy (PMA) of L10-FePd. A micromagnetic simulation assuming both PMA and IPMA predicted that perpendicularly magnetized magnetic tunnel junctions (p-MTJs) using Gr/L10-FePd could realize 10-year data retention in a small recording layer with a circular diameter and thickness of 10 and 2 nm, respectively. We unveiled the energetically stable atomic structure in the crystallographically heterogeneous interface, discovered the emergence of the robust IPMA, and predicted that the Gr/L10-FePd p-MTJ is significant for high-density X nm generation magnetic random-access memory (MRAM) applications.

High-capacity NCNT-encapsulated metal NP catalysts on carbonised loofah with dual-reaction centres over C–M bond bridges for Fenton-like degradation of antibiotics

The intensification of electron transport between the dual-reaction centres in Fenton-like catalyst is demonstrated through the incorporation of carbon-metal (C–M) bond bridges. Herein, nitrogen-doped carbon nanotube-encapsulated Fe3C (Fe3C@NCNT) with dual-reaction centres over short C–Fe bond was constructed through DFT calculation, and accordingly a series of NCNTs-encapsulated Fe/Fe3C, Co, and Mo2C nanoparticles on carbonised loofah were developed by dynamic thermal impregnation and subsequent pyrolysis process. The resultant catalysts displayed satisfactory degradation properties of antibiotics, in which Fe/Fe3C@NCNTs-CL-800 achieved norfloxacin (NOR) removal efficiency of 93.8% in 90 min under neutral pH, and presented excellent cycle stability in NOR removal as well as universality in various antibiotic degradation systems. The remarkable degradation performance of heterogeneous Fenton-like catalysts was attributed to enhancing electron transport to electron-rich M centres over short C–M bond bridges. This study will open a new perspective on the rational design of catalysts for Fenton-like degradation.

Sandwiching Phosphorene with Iron Porphyrin Monolayer for High Stability and Its Biomimetic Sensor to Sensitively Detect Living Cell Released NO.

Instability of 2D phosphorene material is the major obstacle for its broad applications. Herein phosphorene is sandwiched with self‐assembled iron porphyrin monolayers on both sides (I‐Phene) to significantly enhance stability. Iron porphyrin has strong interaction with phosphorene through formation of P—Fe bonds. The sandwich structure offers excellent stability of phosphorene by both‐sided monolayer protections for an intact phosphorene structure more than 40 days under ambient conditions. Meanwhile, the electron transfer between iron porphyrin and phosphorene result in a high oxidation state of Fe, making I‐Phene biomimetic sensitivity toward oxidation of nitric oxide (NO) for 2.5 and 4.0 times higher than phosphorene and iron‐porphyrin alone, respectively. Moreover, I‐Phene exhibits excellent selectivity, a wide detection range, and a low detection limit at a low oxidation potential of 0.82 V, which is comparable with the reported noble metal based biomimetic sensors while ranking the best among all non‐noble biomimetic ones. I‐Phene is further used for real‐time monitoring NO released from cells. This work provides effective approach against phosphorene degrading for outstanding stability, which has universal significance for its various important applications, and holds a great promise for a highly sensitive biomimetic sensor in live‐cell assays.

L-cysteine-modified Fe3 O4 nanoparticles as a novel heterogeneous catalyst for persulfate activation on BTEX removal.

l-cysteine-modified Fe3 O4 nanoparticles (l-cys@nFe3 O4 ) were synthesized successfully and used as catalyst to activate persulfate (PS) for benzene, toluene, ethylbenzene, and xylenes (BTEX) degradation. The composite was fully characterized, and the l-cys@nFe3 O4 had more protrusions and l-cys was combined on the surface of nFe3 O4 . The removals of BTEX were 78.2%, 85.1%, 85.3%, 81.2%, respectively, in PS/l-cys@nFe3 O4 system, while only 52.7% 57.8%, 60.8%, and 56.3% of BTEX removals reached under the same condition for nFe3 O4 chelated with l-cys in 48 h. Four successive cycles of BTEX degradation were completed in PS/l-cys@nFe3 O4 system. The synergistic mechanisms of BTEX degradation in PS/l-cys@nFe3 O4 system were investigated by electron paramagnetic resonance (EPR), benzoic acid (BA) probe and X-ray photoelectron spectroscopy (XPS) tests. SFe bond in l-cys-Fe complexes promoted the electron transfer between nFe3 O4 core and the solution, iron and iron at the interface, thereby promoting the Fe3+ /Fe2+ cycle and the catalytic capacity of nFe3 O4 . The optimal pH of PS/l-cys@nFe3 O4 system was 3, while HCO3 - and Cl- exhibited negative influences on BTEX degradation. Only 14.2%, 15.5%, 15.9%, and 15.6% BTEX had been removed in the presence of 0.12-M PS and 8.0 g/L l-cys@nFe3 O4 under the actual groundwater condition. However, expanding the dosage of PS and l-cys@nFe3 O4 was an effective strategy to overcome the adverse effect. PRACTITIONER POINTS: L-cys@nFe3 O4 were synthesized successfully and used as catalyst to activate PS for BTEX degradation. Four successive cycles of BTEX degradation were completed in PS/L-cys@nFe3 O4 system. lS-Fe bond in L-cys@nFe3 O4 promoted the electron transfer between PS and nFe3 O4 core.

The Besnus transition in 4C pyrrhotite revisited

SUMMARY Ferrimagnetic, monoclinic 4C pyrrhotite (Fe7S8) is the only iron sulphide with high relevance for palaeomagnetism and rock magnetism that can be identified in rock materials by its characteristic low-temperature anomaly. Despite its relevance in natural magnetism and the many magnetic studies over the last decades, the physics and the crystallography behind this anomaly, also denoted Besnus transition, is a matter of debate. In this study, we analyse the static and dynamic magnetization associated with the Besnus transition in conjunction with low-temperature structural data of 4C pyrrhotite reported in the literature. The correlation between the Fe–Fe bonds causing spin-orbit coupling and the dynamic magnetic properties show that the magnetic characteristics of the Besnus transition stem from the interaction of two magnetocrystalline anisotropy systems triggered by thermally induced structural changes on an atomic level in monoclinic 4C pyrrhotite. This refutes the widespread view that the Besnus transition is caused by a crystallographic change from monoclinic to triclinic.

Removal of cesium from liquid radioactive waste by in situ electrochemical synthesis of cesium zinc ferrocyanide

Cesium ion in the simulated liquid radioactive waste was treated with cesium zinc ferrocyanide (CsZnFC) precipitate synthesized by in situ electrochemical synthesis method (ISESM) in this study. The best removal rate of Cs+ was 99.42%, and the residual Cs+ in the effluent was 29.13 μg L‐1 under the optimal experimental conditions of initial pH (pHint) of 7.0, reaction temperature (T) of 35 °C, current density (J) of 0.7 mA cm−2, electrolytic time (t) of 30 min, and molar ratio of [Fe(CN)6]4- to Cs (RFCN/Cs) of 1.0. The synthesized precipitate was characterized by SEM-EDS, XRD and FT-IR. The precipitated particles are cubic with a particle size of around 190 nm. The XRD pattern shows that the phase composition of the synthesized compound is Cs2Zn[Fe(CN)6], and the absorption peaks of O–H bonds, C–N bonds, and C–Fe bonds appear in IR spectrum. The method of in situ electrochemical synthesis of CsZnFC is promising for the treatment of liquid radioactive wastes.

Construction of LaFeO3/g-C3N4 nanosheet-graphene heterojunction with built-in electric field for efficient visible-light photocatalytic hydrogen production

Photocatalytic hydrogen desorption from water has been considered to be a more effective way to solve energy shortages. However, the relatively high charge recombination rate and poor recyclability are the principal factors restricting the realistic utilization of photocatalysts. Herein, in order to improve the utilization of photogenerated carriers and the response range of visible light, a ternary composite material LaFeO3/g-C3N4 nanosheets-graphene had been successfully prepared. A series of systematic studies on the structure, microscopic morphology, magnetic properties and photocatalytic hydrogen evolution activity have been carried out. The combination of CNNS, LaFeO3 and graphene in the composites was confirmed by XRD and XPS. SEM and TEM results show that LaFeO3 micro-particles grow uniformly on the CNNS flaps and the graphene is observed to cover the surface of the LaFeO3/CNNS. The optical properties indicate that the absorption edge of the composite material extends to the visible light region. The excellent photocatalytic performance of LFO/CNNS-0.25G composite (1326.5 μmol h−1 g−1) is mainly result in the improved redox capacity and carrier separation due to the tight C–O–Fe bond of Z-scheme heterojunction, meanwhile, the introduction of graphene also broadens the visible light response and accelerates the carrier transport. This research can provide a novel strategy for designing artificial photocatalytic systems with high charge transfer efficiency.

Structure and physical properties of Li2O–Fe2O3–P2O5 glasses

The structure and physical properties of (50−x)Li2O·xFe2O3·50P2O5 glasses (0 ≤ x ≤ 25 mol%) have been studied by different techniques. The amorphous nature of the glasses has been affirmed by x-ray diffraction. By increasing Fe2O3 content, the Fe/P ratio increases, and the covalent P–O–Fe bonds also increase, which leads to a more durable structure. For Fe2O3 ≤ 15 mol%, Fe ions enter the network as a network modifier breaking P–O–P and P = O bonds and act as a network former for Fe2O3 > 15 mol%. Hardness (H v) increases with increasing Fe2O3 content because of the strengthening of the network. Studying the chemical durability of the investigated glasses has shown that the compositions containing high content of iron oxide are more water−resistant. Moreover, density and molar volume increase with different rates with Fe2O3 content. It is believed that the conduction in these glasses is predominantly ionic and dominated by Li+ ions as the main charge carriers. The contribution of the polarons to the conduction process has a negligible impact compared to that of the ionic conduction by Li+ ions. Regarding the shielding properties, the mass attenuation coefficient was calculated by the XCOM program and other photon shielding properties like mean free path (λ), and half value layer (HVL) were calculated within the energy range of 0.335 MeV-9 MeV. The effect of replacing lithium oxide by iron oxide has been analyzed which proved that iron is more efficient than lithium in attenuating and removing fast neutrons.

Effect of Fe doping on structural, elastic and electronic properties of B2–ZrCu phase under hydrostatic pressure: A first-principles study

The effects of Fe doping and applied hydrostatic pressure on structural, mechanical and electronic properties of Zr8Cu8-xFex (x = 0, 1, 2, 3) are investigated via the first-principles calculations. The equation of state (EOS) is established for B2–CuZr crystalline structure. The values are in good agreement with previous experimental results. The phase stability is improved simultaneously by the substitution of Fe for Cu and enhanced hydrostatic pressure for Zr8Cu8-xFex (x = 0, 1, 2, 3). Doping concentration plays an important role in tuning the values of bulk modulus B. However, the values of Vickers hardness HV follows the sequence as: Zr8Cu6Fe2 > Zr8Cu7Fe1 > Zr8Cu5Fe3 > Zr8Cu8 (0–30 GPa). The sequence of B/G, Poisson's ratio ʋ is just opposite to that of HV. It implies a strong correlation between ductility and charge density topology (closely related to bonding character and substitutional atomic sites). Substitution of Fe for Cu tailor the metallic characteristic of Zr–Cu bond into more directional covalent characteristic of Zr–Fe bond, thus make doped Zr8Cu8-xFex (x = 1, 2, 3) harder and more brittle than non-doped Zr8Cu8. The hydrostatic pressure generally enhances the predominant metallic character of Zr8Cu8-xFex (x = 0, 1, 2, 3), thus make all doped and non-doped compositions transit into a more ductile regime. The combined effects of directional bonding and pressurizing thus make Zr8Cu6Fe2 (0 GPa) the most hard and brittle material and Zr8Cu8 (30 GPa) the most ductile material among all compositions.

Effect of S on H-induced grain-boundary embrittlement in γ-Fe by first-principles calculations

The effect of interstitial impurities (H and S) on the atomic, electronic structure, and mechanical properties of the γ-Fe Σ5 (021) grain boundary (GB) was investigated via first-principles calculations. H atoms act as an intergranular embrittler in the Σ5 GB due to a reduction in the charge density between the Fe atoms connected to the grains, whereas H and S co-segregation produces more pronounced embrittlement behavior, resulting in intergranular fracture. The S-induced embrittlement plays a crucial role in the H and S segregation, due to a combination of the structural and chemical effects. The fracturing of Σ5 GB due to S and H segregation is a two-step process. The first step is the breaking of Fe–Fe bonds in the GB, followed by the breaking of the remaining Fe–S bonds in the second step, resulting in the complete separation of the two grains. Moreover, the S atom can slightly compensate for the embrittlement induced by H, because some of the Fe atoms that obtain electrons from the S atoms can provide more electrons to the H atoms, and thus, they can compensate for the electrons that must be acquired from other Fe atoms. We call this “the electrons compensating effect” and this effect is helpful in the design and alloying of steels that are resistant to H embrittlement.

Study on transition metal ion Fe3+ catalyzed biodiesel oxidation and inhibition mechanism

Methyl linoleate is used as an alternative component of biodiesel. The catalytic oxidation of biodiesel is studied in the presence of iron acetate using methyl linoleate as the alternative component. The composition of the products obtained from the oxidation process of methyl linoleate is analyzed by GC–MS and liquid phase microextraction. Density functional theory is used to calculate the electronic effects of the related reactants and products and the related catalytic oxidation reaction paths are derived. The results show that during the process of catalytic oxidation of methyl linoleate in biodiesel, mainly the catalytic cracking reaction of C–H and C–C bonds and Fenton-like reaction occur. The combination of two antioxidants, TEPA and [MI][C6H2(OH)3COO], can effectively inhibit the catalytic oxidation of Cu2+ and Fe3+ and interrupt the chain reaction of the oxidation process. The negative value of the electrostatic potential of ferric acetate is relatively large, it is obviously alkaline, and has a certain ability to bind with H. The irregular structure of the iron acetate unit cell makes the O–Fe bond in the molecule easy to break, which is beneficial for the catalytic oxidation process.

Self-diffusion processes in stoichiometric iron mononitride

In this work, we studied atomic self-diffusion and structural phase transformation in a single phase iron mononitride (FeN) thin film deposited at an optimized substrate temperature (Ts) of 423 K. At this Ts, the FeN film exhibits a tetrahedral coordination between Fe and N atoms (ZnS-type structure with a lattice parameter of 4.28 Å). The structure of the FeN film was studied by combining x-ray diffraction with Fe and N K-edge x-ray absorption spectroscopy and conversion electron Mössbauer spectroscopy measurements. Self-diffusion of Fe and N was measured using secondary ion mass spectroscopy depth profiling in trilayer structures: [FeN(50 nm)/57FeN(2 nm)/FeN(50 nm)] and [FeN(50 nm)/Fe15N(2 nm)/FeN(50 nm)] deposited on an amorphous quartz substrate using reactive magnetron sputtering. It was found that atomic self-diffusion is strongly associated with thermal stability. Before reaching the phase decomposition temperature, the self-diffusion of N was found to be slower than Fe. Upon phase decomposition, both Fe and N diffuse rapidly, and at this stage, the self-diffusion of N takes over Fe. Within the thermally stable state, slower N diffusion indicates that Fe–N bonds are stronger than Fe–Fe bonds in FeN. This behavior was predicted theoretically and has been evidenced in this work.

Structural, optical, and magnetic evaluation of Co-, Ni-, and Mn-modified multiferroic BiFeO3 ceramics

Co-, Ni-, and Mn-doped BiFeO3 (BFO) ceramics were synthesized herein through a solid-state reaction. All doped BFO samples exhibit visible-light response, and the Co- and Ni-doped BFO samples present enhanced ferromagnetic order at room temperature. All doped samples show secondary phases in minor quantities. Optical spectra reveal two absorptions bands, indicating multiple electron transitions for BFO and its secondary phases. M − H hysteresis loops suggest enhanced ferromagnetism in the Co- and Ni-doped BFO samples because of magnetic spinel CFP and NFO phases, respectively, whereas changes in oxygen vacancies and Fe–O–Fe bond angle play minor roles in the ferromagnetic behavior.

Multi-walled carbon nanotubes facilitated Roxarsone elimination in SR-AOPs by accelerating electron transfer in modified electrolytic manganese residue and forming surface activated-complexes

A novel catalyst (MT/EMR) used for SR-AOPs with high removal efficiency toward roxarsone (ROX) (90.96% within 60 min) was prepared for the first time by ball milling multi-walled carbon nanotubes (MWCNTs) with electrolytic manganese residue (EMR). The incorporation of MWCNTs could improve the adsorption capacity and accelerate the transformation of metals in EMR with partial mass loss to facilitate the PDS activation. Additionally, pH test, quenching experiment and electrochemical test verified a two-electron pathway involving surface activated-complex contributed to the directly ROX oxidization. Benefit from the introduction of MWCNTs, the degradation rate (kobs) of catalytic reaction was increased by 10.1 times compared with that of single-EMR. Additionally, the M-O-C (M=Fe or Mn) bonds in MT/EMR making the catalyst more stable than EMR. This work provided a novel and effective strategy to establish waste solid-based catalysts for green preparation and expanded the adsorption-oxidation technology to solve the problem of organoarsenic pollution.

Reactive molecular dynamics study of the oxidation behavior of iron‐based alloy in supercritical water

AbstractA theoretical study of the oxidation behavior of iron‐based alloy in the supercritical water (SCW) has been carried out based on ReaxFF force‐field molecular dynamics simulation. An atomic model has been proposed to simulate the initial chemisorption reactions and atoms diffusion behavior across the oxide layer. Simulation results imply that Cr addition has an important effect on the oxidation behavior of iron‐based alloy. In the initial stage of oxidation, H2O prefers to adsorb on the Cr atom, and some species in the form of Cr(OH)4 are observed on the FeCr alloy surface. Once an initial oxide layer is formed, further oxidation is controlled by the migration of vacancy. The O vacancies are formed at the oxide/FeCr alloy interface and migrate toward the steam, whereas Fe vacancies are formed at the oxide/steam interface and migrate toward the FeCr alloy. Attributed to the stronger binding energy of O–Cr bond than O–Fe bond, the Cr diffusivity in the oxide is less than Fe atoms. Thus, double oxide layers, including the inner Fe–Cr–O layer and outer Fe–O layer, are formed on the FeCr alloy, which is in good agreement with previous experimental observation.

Effect of Mo concentration on structural, mechanical, electronic and magnetic properties of Fe2B: a first-principles study

ABSTRACT First-principles calculations were performed to study the structural, mechanical, electronic and magnetic properties of Fe(8−x)Mo x B4 (x = 0, 0.25, 0.5, 1, 2, 3, 4, 5, 6, 7, 8). Results show that the Mo atoms would enter the Fe2B lattice by replacing the Fe atoms and cause a change in the crystal structure. According to the calculated formation enthalpy, all borides are thermodynamically stable; moreover, Mo would reduce the stability of Fe2B when the Mo atomic number is less than four in the unit cell. On the whole, with the increase of Mo content, the Young’s moduli and shear moduli decrease firstly and then increase, while the bulk moduli get bigger. Although the hardness of Fe2B would decline with increasing Mo content, Mo is an excellent candidate for improving the ductility of Fe2B on the basis of the G/B and Poisson’s ratio ν values. The charge density plots indicate that the integral strength of the linear boron chains in [002] orientation is reduced in Mo-alloyed Fe2B. The toughness improvement of Fe2B would be attributed to the evolutions of B–B bonds, Fe/Mo–B bonds and Fe/Mo–Fe bonds, which may induce the deflection of the Fe2B cleavage plane. Besides, the magnetic moments of these borides monotonically decrease with the increase in Mo content.