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As an extension of single-atom catalysts, despite the increased opportunities to optimize the hydrogen evolution reaction (HER) activity with the variation of the composition, dual-metal-atom catalysts, i.e., dimers, are deeply trapped in a design blind spot due to the lack of the essential recognition of the intrinsic catalytic mechanism at the atomic level. Herein, based on first-principles calculations, a series of platinum-transition metal dimers were constructed on nitrogen-doped graphene (PtM-NDG, M = Fe, Co, Ni, Cu) to reveal the effects of the internal (i.e., M atom) and external (i.e., NDG substrate) environments on the HER activity. Computational results show that the original over-adsorption of hydrogen intermediate (H*) of PtM dimer is weakened after the introduction of NDG, and the optimal active site migrates from the Pt in PtM dimer to the Pt-M bridge in PtM-NDG, triggered by the redistribution of the charge density of the metal atoms. In particular, the M atom switches from tuning the d-band center of the Pt atom to indirectly assist the adsorption behavior of Pt in the PtM dimer to the direct participation in the bonding with H* in PtM-NDG via its own d-band to regulate the distribution of σ and σ*, which enables fine modulation of the bond strength with H*. Moreover, the overall hydrogen evolution performance of PtM-NDG is mainly determined by the d-band center of the M atom. Furthermore, PtFe-NDG with the lowest energy barrier of the rate-determining step stands out in the process of H

The emergence of superconductivity in doped insulators such as cuprates and pnictides coincides with their doping-driven insulator-metal transitions. Above the critical doping threshold, a metallic state sets in at high temperatures, while superconductivity sets in at low temperatures. An unanswered question is whether the formation of Cooper pairsin a well-established metal will inevitably transform the host material into a superconductor, as manifested by a resistance drop. Here, this question is addressed by investigating the electrical transport in nanoscale rings (full loops) and half loops manufactured from heavily boron-doped diamond. It is shown that in contrast to the diamond half-loops (DHLs) exhibiting a metal-superconductor transition, the diamond nanorings (DNRs) demonstrate a sharp resistance increase up to 430% and a giant negative "magnetoresistance" below the superconducting transition temperature of the starting material. The finding of the unconventional giant negative "magnetoresistance", as distinct from existing categories of magnetoresistance, that is, the conventional giant magnetoresistance in magnetic multilayers, the colossal magnetoresistance in perovskites, and the geometric magnetoresistance in semiconductor-metal hybrids, reveals the transformation of the DNRs from metals to bosonic semiconductors upon the formation of Cooper pairs. DNRs like these could be used to manipulate Cooper pairs in superconducting quantum devices. ispartof: ADVANCED MATERIALS vol:35 issue:22 ispartof: location:Germany status: Published online

Due to the wide use of iron in all kinds of areas, the design and construction of direct, fast, and highly sensitive sensor for Fe3+ are highly desirable and important. In the present work, a kind of fluorescent MXene quantum dots (MQDs) was synthesized via an intermittent ultrasound process using N,N-dimethyl formamide as solvent. The prepared MQDs were characterized via a combination of UV–Vis absorption, fluorescence spectra, X-ray photoelectron energy spectra, and Fourier-transform infrared spectroscopy. Based on the electrostatic-induced aggregation quenching mechanism, the fluorescent MQDs probes exhibited excellent sensing performance for the detection of Fe3+, with a sensitivity of 0.6377 mM−1 and the detection limit of 1.4 μM, superior to those reported in studies. The present MQDs-based probes demonstrate the potential promising applications as the sensing device of Fe3+.

Metallic nanocrystals with specific morphologies are of great interest to various applications, in particular for nanocages with well-defined and controllable surface due to high surface-to-volume ratio with high utilization efficiency of atoms. In the present work, Ru decahedral nanocages were synthesized via a combination of seed-mediated growth and chemical etching approach over Pd decahedra seeds. To be specific, the Pd decahedra were synthesized via a standard procedure, on which the Ru out layers were grown by seed-mediated growth with a few nanometers. Subsequently, Ru decahedral nanocages were formed with selective chemical etching of Pd cores in acidic aqueous solution. The present work suggests an effective strategy towards synthesis of hollow nanocages.

Based on its excellent visible light absorption and photoelectric response capabilities, SbSI has attracted significant research attention for a wide range of applications. Despite the fact that interesting physical properties can be induced from the sophisticated band structures of SbSI, that is, either with direct or indirect band gaps, its nonlinear optical (NLO) properties are not yet fully explored. In the present work, the NLO response of SbSI nanorods is investigated by the combination of open-aperture (OA) Z-scan, pump–probe, and spatial self-phase modulation (SSPM). It is found that the synthesized SbSI nanorods possess a relatively large nonlinear absorption coefficient and a small saturable optical intensity at a wavelength of 400 nm, compared to those of other materials. More importantly, the OA Z-scan experiments suggest that the direct band gap of SbSI plays a dominant role on the NLO effects, which is further verified by the SSPM experiments. The present work suggests that the SbSI nanorods may have great potentials for optical switches and saturable absorbers.

Despite the recent efforts and progress on the transition metal-based electrocatalysts for water splitting, it is still a challenge to fabricate oxygen evolution reaction electrocatalysts with high performance, simultaneously via a simple, facile, and environment-friendly way. Herein, we report a facile strategy for the fabrication of NiFe oxides-based micro/nano-structures on Ni foams via simple femtosecond laser ablation, where the Ni : Fe ratio can be readily tuned by changing the amount of Fe precursors dropped on the Ni foams. The resulted electrocatalysts exhibit excellent oxygen evolution reaction activity with low overpotentials of 221 and 241 mV at 25 and 50 mA cm−2, and good long-term durability under high current density in alkaline condition, suggesting great potentials for practical applications.

Although there is a general consensus that the electrocatalysts will undergo reconstruction to generate (oxy)hydroxides as real active sites during the electrochemical oxygen evolution reaction (OER), the understanding of this process is still far from satisfactory. In particular, the reconstruction process of most of these electrocatalysts is either slow or occurs only on the surface, which thus restrains the OER performance of the electrocatalysts. Herein, we reveal a fast and deep reconstruction of the coprecipitated Fe phosphates on nickel foam, via in situ Raman spectroscopy together with electron microscopy, X-ray photoelectron spectroscopy, and electrochemical tests. The generated NiFe (oxy)hydroxide nanosheets after reconstruction behave as the real active sites for the OER in the alkaline condition, with a low overpotential and excellent durability. The present work provides deep insights on the reconstruction dynamics of OER electrocatalysts.

The saturable absorption properties of BiOI nanosheets with exposed {110} facets prepared by the chemical vapor transport were investigated by Z-scan with femtosecond pulse laser. The nonlinear absorption coefficient at 400 nm is stronger and more sensitive to photoexcitation than its nonlinear response at 800 nm. The small saturation intensity could have been achieved, which is one order of magnitude smaller than that of black phosphorus nanosheets, while the I m χ ( 3 ) are determined to be − 4.35 × 10 − 12 e s u close to theoretical prediction. According to time-resolved photoluminescence spectrum results, this strong saturated absorption at 400 nm may be attributed to the interband recombination process, whose lifetime was 230 ps.

Due to widely use of iron in all kinds of areas, the design and construction of direct, fast, and highly sensitive sensor for Fe3+ is highly desirable and important. In the present work, a kind of fluorescent MQDs were synthesized via an intermittent ultrasound process with N,N-dimethyl formamide as solvent. The prepared MQDs were characterized via a combination of UV-Vis absorption, fluorescence spectra, X-ray photoelectron energy spectra, and Fourier transform infrared spectroscopy. Based on the electrostatic induced aggregation quenching mechanism, the fluorescent MQDs probes exhibited excellent sensing performance for the detection of Fe3+, with a sensitivity of 0.6377 mM− 1 and the detection limit of 1.4 µM, superior to those reported in literatures. The present MQDs-based probes demonstrate potential promising applications as the sensing device of Fe3+.

The development of simple and effective methods for the rapid preparation of electrocatalysts for overall water splitting from earth-abundant elements is an important and challenging task. A facile and ultrafast two-step method was developed to prepare a Ni/NiO@CoFe layered double hydroxide hierarchical nanostructure (NCF) within a few minutes by femtosecond laser ablation and electrodeposition. In 1 m KOH solution, the optimized NCF catalysts show a low overpotential of 230 mV for the oxygen evolution reaction (OER) at a current density of 10 mA cm-2 with a low Tafel slope of 34.3 mV dec-1 , indicating fast and efficient OER kinetics. Owing to the synergistic effect between NiO and CoFe layered double hydroxide, the hydrogen evolution reaction performance of the NCF was also improved. The synthesized electrocatalysts were further utilized in overall water splitting with a potential of only 1.56 V at a current density of 10 mA cm-2 and excellent durability, better than that of the commercial RuO2 (+)//Pt/C(-) system. The present work provides new insights on the rapid and facile preparation of efficient electrocatalysts for overall water splitting on a large scale.

Black phosphorus (BP), a new rediscovered 2-dimensional material, has gained enormous attention in the field of electrocatalysis, particularly for oxygen evolution reactions. However, its easily being oxidized nature and the bulk crystal structure restricts sufficient active sites, which severely hinders its potential applications in catalysis. Herein, BP nanosheets are prepared and deposited with Co(OH)2 nanosheets to construct the Co(OH)2/BP interfaces. Owing to the high Fermi level of Co(OH)2 than that of BP, the electrons are transferred initiatively from Co(OH)2 to BP, affording remarkable oxygen evolution reaction performance with an overpotential of 276 mV at a current density of 10 mA cm−2. Moreover, the potentiostatic tests present decent electrocatalytic stability of the synthesized Co(OH)2/BP nanosheets. It is further anticipated that engineering the interface towards manipulating the charge density on BP surface and/or interface by depositing other kind of catalysts could be a straightforward strategy to design outstanding hybrid electrocatalysts.

Solar desalination is a sustainable, low-cost and eco-friendly method for water purification. Current methods for solar evaporation desalination suffer from relatively low efficiencies, complex preparations, high cost, and instability. Here, for the first time, we propose a femtosecond laser structured Ti foam for use in a rapid steam escaping evaporator for solar steam generation. The assembled device has a high water evaporation rate of ∼1.79 kg m−2 h−1 and a solar steam efficiency of ∼90% under one sun irradiation. The device is constructed from a treated Ti foam, insulation cotton and polyurethane sponge. The treated Ti foam possesses efficient broadband solar absorption (>97%), Janus characteristics (superhydrophilicity/hydrophobicity) for pumping water on the vapor surface, and superaerophobicity for rapid vapor release, all of which facilitate confined water evaporation. The underlying insulation cotton alleviates thermal dissipation. The pre-wetted polyurethane sponge supplies water to the Ti foam, thus avoiding direct contact between the treated foam and bulk water. Promisingly, a home-made system was built to verify the feasibility of generating purified water. The femtosecond direct writing technology provides a rapid approach for efficient desalination using natural sunlight.

Long hexagonal Co3(PO4)2·4H2O nanosheets were synthesized using a hydrothermal method, where their nonlinearity was probed via a femtosecond Z-scan system. The results show that the Co3(PO4)2·4H2O nanosheets exhibit saturable absorption when the incident photon energy is greater than the forbidden band width, while optical limiting is found when the incident photon energy is smaller than the forbidden band width. In particular, the obtained Co3(PO4)2·4H2O nanosheets demonstrate the best optical limiting properties at 600 nm. The present study suggests the cobalt phosphates nanosheets as a promising candidate for optical limiters.

The picosecond dynamics of excited charge carriers in the silicon substrate of THz metamaterial antennas was studied at different wavelengths. Time-resolved THz pump-THz probe spectroscopy was performed with light from a tunable free electron laser in the 9.3–16.7 THz frequency range using fluences of 2–12 J/m2. Depending on the excitation wavelength with respect to the resonance center, transient transmission increase, decrease, or a combination of both was observed. The transient transmission changes can be explained by local electric field enhancement, which induces impact ionization in the silicon substrate, increasing the local number of charge carriers by several orders of magnitude, and their subsequent diffusion and recombination. The studied metamaterials can be integrated with common semiconductor devices and can potentially be used in sensing applications and THz energy harvesting. ispartof: Optics Express vol:29 issue:1 pages:170-181 ispartof: location:United States status: published

supplementary informations

Marks decahedral nanoparticles have attracted significant attention in recent years. In this work, a method of synthesizing Marks decahedron via etching regular decahedral nanoparticles is proposed and verified by Pd nanoparticles, which shows a high yield of Marks decahedron. The present work suggests that one can tune the concave size of Marks decahedral via controlling the etching time and the amount of Poly(vinyl pyrrolidone) (PVP). The thermal stability of Marks nanoparticles is explained by Bond-Energy model, which predicts the largest groove to be the most stable configuration. Moreover, the present method can be extended to synthesize Marks decahedral nanoparticles of other elements, and is of great significance for further studies and applications of Mark decahedral nanoparticles.

A theoretical model is developed to systematically study the effect of the matrix on the order-disorder phase transition of FePt nanoparticles, which shows a significant role of the matrix or substrate to the ordering kinetics of FePt nanoparticles during the annealing process. It is shown that there exists a temperature window where one can obtain ordered FePt phase, while the high temperature limit with the largest nucleation rate is favorable for the formation of ordered FePt phase (L10). The matrix or substrate not only reduces particle agglomeration and sintering, but also increases the high temperature limit as well as nucleation rate. Furthermore, the effect of the matrix to the ordering kinetics of FePt nanoparticles relies on its surface energy, the higher the surface energy of the matrix is, the more pronounced the effect is. The validity of the present model is supported by as well the explanations of the contradiction results as the good agreement between the model predictions and experimental data. Those findings are very interesting and crucial for practical application when synthesizing ordered FePt nanoparticles.

Combining two different layered structures to form van der Waals (vdW) heterostructure has recently emerged as an intriguing way of designing electronic and optoelectronic devices. Using first-prin...

The cohesive energy, formation enthalpies, and elastic constants of AgAl, AuAg, AuPd, AuPt, CuNi, CuPt, NiPb, NiPd, NiPt, and PtPd alloys are calculated by molecular dynamics simulation and first-principle calculation. It is found that the calculated formation enthalpies generally agree with the availible experimental data. The Debye temperatures of these alloys with different compositions are computed from the obtained elastic constants. An empirical relationship between Debye temperature and cohesive energy is developed, which is confirmed by both the simulation and calculation.

Platinum and palladium (PtPd) alloy nanoparticles (NPs) are excellent catalysts for direct methanol fuel cells. In this study, we developed PtPd alloy NPs through the co-reduction of K2PtCl4 and Na2PdCl4 in a polyol synthesis environment. During the reaction, the feed molar ratio of the two precursors was carried over to the final products, which have a narrow size distribution with a mean size of approximately 4 nm. The catalytic activity for methanol oxidation reactions possible depends closely on the composition of as-prepared PtPd alloy NPs, and the NPs with a Pt atomic percentage of approximately 75% result in higher activity and stability with a mass specific activity that is 7 times greater than that of commercial Pt/C catalysts. The results indicate that through composition control, PtPd alloy NPs can improve the effectiveness of catalytic performance.

CuPt nanodendrites have special electrocatalytic performance due to their unique morphologies and structures. In this work, we report a facile and one-pot synthesis of highly branched and dispersed CuPt nanodendrites with a size of about 22 nm and Pt/Cu ratio of 2 : 1. X-ray photoelectron spectra indicate a Pt-rich surface of the prepared CuPt nanodendrites. The combination of a highly branched structure with a Pt-rich shell would be very beneficial for catalytic properties, which was confirmed by electrochemical tests towards MOR. A systematic study on morphology evolution of the products and understanding of their growth mechanism was carried out using the effects of reaction time and reducing agents.

NbMoTaW refractory high entropy alloy (RHEA) possesses superior high temperature mechanical strength while the very low plastic strain at room temperature limits its practical applications. In present work, the method of adjusting composition was employed to improve the mechanical properties of (NbTaW)1−xMox (x = 0, 0.05, 0.15, 0.25) alloys especially the plasticity at room temperature by the combination of experiments and first-principles calculations. Phase composition of the (NbTaW)1−xMox alloys identified using experiments and theoretical prediction were all single-phase solid solution. Microstructure and elements distribution of the alloys were characterized by SEM and EDS. All the as-casted alloys had dendrite structures and the grain size firstly increased (x 0.15) with the increase of Mo content. The compressive properties and the analysis of fracture surface demonstrated that strength and ductility of (NbTaW)1−xMox alloys were obviously enhanced with the decrease of Mo content. NbTaW MEA had the maximum mechanical strength (1460 MPa) and ductility (16.2%) in the designed alloys. Both the mechanical strength and plasticity at room temperature were greatly improved compared with that of NbMoTaW RHEA. The experimental results well agreed with that of first-principles calculations. The elastic anisotropy and microhardness of these alloys were also predicted. The orders of elastic anisotropy were (NbTaW)0.75Mo0.25

Atomic layer deposition (ALD) is a vapor phase technique capable of producing a variety of materials. It consists of the alternation of separate self-limiting surface reactions, which enables accurate control of film thickness at the Angstrom level. ALD becomes a powerful tool for a lot of industrial and research applications. Coating strategies are the key for ALD; however, there are few systematic reviews concerning coating strategies for ALD. This review provides a detailed summary of state-of-the-art coating strategies in ALD, emphasizing the recent progress in the fabrication of novel nanostructures. The progress in coating strategies is reviewed in three parts: template-assisted preparation of low-dimensional nanomaterials and complex nanostructures; surface treatments, including the surface activation and the surface blocking ways; enhanced reactor, such as plasma and fluid bed reactor, and improved growth method such as the ABC-type model. In addition, we also discussed the challenges facing the coating method for ALD.

Water electrolysis shows great promise for the low-cost mass production of high-purity hydrogen. The relatively high dissociation energy of water, however, often results in rather sluggish kinetics of the hydrogen evolution reaction (HER) in alkaline conditions, even for the case of state-of-the-art Pt-based electrocatalysts. Here, we show the high efficiency of the hybrids of PtRu nanoclusters (NCs) and black phosphorus (BP) nanosheets in HER. Our PtRu NCs/BP electrocatalysts demonstrate a HER activity of 88.5 mA cm -2 at -70 mV in 1 M KOH, which is higher than that of commercial Pt/C by 1 order of magnitude. The observed extraordinarily high HER activity of the PtRu NCs/BP hybrids is interpreted in the framework of density functional theory. Theoretical modeling indicates that the electronic interaction between BP and PtRu NCs speeds up the dissociation of water and optimizes the adsorption strength for H∗ species, giving rise to the remarkably high HER activity of the PtRu NCs/BP hybrids.

Highly efficient and low-cost non-noble metal based electrocatalysts for oxygen evolution reaction (OER) have attracted more and more attention in recent years. However, the current research has been focused on the construction of novel OER electrocatalysts themselves, little attention has been paid to the modification of the substrates. In this work, a different strategy is proposed via laser ablation to fabricate the Cu foams with rich micro/nano-structures as OER substrates. Later, the precipitation conversion method was utilized to grow cobalt hydroxide on the laser fabricated Cu foams. The as-produced Cu/Cu oxides/Co(OH)2 electrocatalysts exhibit high OER activity in 1 M KOH, requiring an overpotential of only 259 mV at a current density of 50 mA cm−2 with excellent mild-term durability. The improved catalytic performance of the prepared samples can be attributed to the increased surface area, rich active sites, and the superhydrophilicity of the laser produced micro/nano-structures.

Poor ductility of Refractory high entropy alloys (RHEAs) at room temperature (RT) is the main problem restricting their practical applications. Alloying is an effective method to improve the mechanical properties of RHEAs. Here, Ti was employed to enhance the RT ductility of NbTaMoW RHEAs by means of alloying. The influence of Ti addition on the mechanical properties of the equiatomic NbTaMoW RHEA was investigated from the perspective of first-principles calculation combining experiments. The phase structure, lattice parameters, densities, elastic properties and electronic structure were calculated, respectively. The results show that NbMoTaW and NbMoTaWTi alloy were single-phase BCC structure. Both alloys were electrically conductive and shown metallic characteristic. Ti alloying effectively enhanced the atomic interaction, strength and ductility of NbMoTaW alloy due to the increasing Ti–Ti metallic bonds and decreasing covalent bonds. The calculated data were well agreed with the experimental results, demonstrating that first-principles calculation was an effective method to predict the alloying performance enhancement of RHEAs.

The structure of cobalt-doped silicon clusters, SinCo+ (n = 5–8) and SinCo2+ (n = 8–12), is investigated in a combined infrared multiple photon dissociation spectroscopy and density functional theory study. The singly doped clusters have exohedral structures in which the Co atom substitutes an atom of bare Sin+1+ clusters. In the doubly doped SinCo2+ clusters, the second Co atom is adsorbed to the singly doped counterparts and, for n ≥ 9, one of the Co atoms is encapsulated by a silicon cage. Computational analysis of the electronic and magnetic properties of the identified isomers indicates a distance dependent magnetic coupling between the Co atoms in the SinCo2+ clusters.

The development of industrial application of water splitting demands simple and effective methods for the preparation of highly efficient electrocatalysts that are inexpensive and robust. Herein, we report a simple activation method to decorate 3D cobalt iron oxyhydroxide (CoFe-OOH) nanosheets on Co2P nanoparticles with Ni foams (NF) as substrates. The synthesized catalysts exhibit excellent activity for electrochemical oxygen evolution reaction due to the hierarchical heterostructures and synergistic effects of CoFe-OOH and Co2P. The as-prepared catalysts require a low overpotential of 199 mV to deliver 30 mA cm−2 in oxygen evolution reaction in 1 M KOH with a small Tafel slope of 39 mV dec−1, indicating favorable kinetics during electrolysis. The synthesized catalysts are further used as cathode and anode for overall water splitting, which only requires a cell voltage of 1.60 V at a current density of 30 mA cm−2. This work provides new insights on the preparation of efficient electrocatalysts for overall water splitting, which may have the potentials for industrial water electrolysis.

NbMoTaW refractory high entropy alloy (RHEA) has shown great potential applications for high temperature components due to its high temperature mechanical strength. However, the brittleness at room temperature hinders its engineering application and further development. To overcome this deficiency, refractory alloying elements with melting temperatures over 1850 °C, i.e., Cr, Zr, V, Hf, and Re, were chosen to enhance the mechanical performance of NbMoTaW RHEA in the present work. The effects of refractory alloying elements on the strength and ductility of NbMoTaW RHEA were investigated via a combination of theory and experiment. To be specific, the first-principle calculations based on density functional theory were employed to predict the mechanical properties of the alloyed NbMoTaWX (X = Cr, Zr, V, Hf and Re) RHEAs and explain the alloying effect from the atomic and electronic level. Moreover, the phase structures of the alloyed RHEAs were determined based on the formation enthalpy and cohesive energy, as well as some empirical parameters, such as the average valence electron concentration VEC and atomic size difference δ. In combination with the experimental results, the calculated elastic constants and modulus indicated that most of these alloying elements enhanced the strength of NbMoTaW RHEA, while only Zr-alloying significantly improved the ductility. The strengthening mechanism of different elements was well analyzed based on the total and partial density of states, overlapping Mulliken population, charge density contour, and atomic distance. The improvement of the ductility for Zr-alloying was attributed to the formation of Zr–Zr metallic bonds in the alloyed NbMoTaWX RHEAs. The theoretic predictions were confirmed by the experimental investigations. The present work provides a good guidance for design and construction of NbMoTaW RHEA.

A sandwich structure of black phosphorus nanosheets coupled with MoS2 nanosheets was prepared via liquid exfoliation and hydrothermal methods. An enhancement of saturated absorption was observed at the long wavelength of 1550 nm via the femtosecond Z-scan technique, which is much stronger than its nonlinear response at 400 and 800 nm. According to the ultrafast pump-probe results, this strong saturated absorption can be attributed to the dominant role of a slow relaxation process, corresponding to the enhanced interface and defects effects. Moreover, the nonlinear refractive properties were found to transform from self-focusing to self-defocusing with the increasing of excitation wavelength from visible to near-infrared region, which can be qualitatively explained by an effective medium approach, similar to noble metal nanomaterials. These results suggest that the synthesized MoS2/BP/MoS2 may have potential applications for nonlinear optical devices.

Alloying is an effective method to strengthen high entropy alloys (HEAs). Unfortunately, most of the investigations focus on the perspective of experiments and few are available from the perspective of atomic and electrical scale such as electronic structure, energy band structure and charge density. In present work, first-principle calculation based on density functional theory was employed to calculate the ground state total energy, lattice parameters, elastic constants and polycrystal modulus of NbMoTaW and NbMoTaWV refractory high entropy alloys (RHEAs). The effects of V addition on the phase structure, elastic properties and electronic structure of NbMoTaW-based RHEAs were studied, respectively. V addition is helpful to improve the mechanical properties of NbMoTaW alloy according to the calculated value of shear modulus to bulk modulus, Cauchy pressure and Vickers hardness. Based on calculated energy band, electronic state density, charge density and charge density difference, V addition is found to shorten the pseudo-energy gap and enhance interaction force between Mo and W atoms. This tends to improve the mechanical properties of the alloy. The calculated results were in good agreement with the experimental data, demonstrating that the methods were effective in predicting the performance of RHEAs.