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Constructing metal-semiconductor interfaces by loading metal atoms onto two-dimensional material to build atomically dispersed single-atom catalysts (SACs) has emerged as a new frontier for improving atom utilization and designing multifunctional electrocatalysts. Nowadays, studies on black phosphorus nanosheets in electrocatalysis have received much attention and the successful preparation of metal nanoparticle/black phosphorus (BP) hybrid electrocatalysts indicates BP nanosheets can serve as a potential support platform for SACs. Herein, by using large-scale ab initio calculations, we explored a large composition space of SACs with transition metal atoms supported on BP monolayer (M-BP) and built a comprehensive picture of activity trend, stability, and electronic origin towards oxygen reduction and evolution reaction (ORR and OER) and hydrogen evolution reaction (HER). The results show that the catalytic activity can be widely tuned by reasonable regulation of metal atoms. Ni-, Pd-, and Pt-BP could effectively balance the binding strength of the target intermediates, thus achieving efficient bifunctional activity for OER and ORR. Favorable bifunctional catalytic performance for OER and HER can be realized on Rh-BP. Especially, Pt-BP exhibits promising trifunctional activity towards OER, ORR, and HER. Multiple-level corrections among overpotential, Gibbs free energy, orbital population, and d-band center reveal that the trend and origin of catalytic activity are intrinsically determined by the d-band center of metal sites. The thermodynamic and dynamic stability simulations demonstrate that the active metal centers are firmly anchored on BP substrate with intact M-P bonds. These findings provide a theoretical basis for the rational design of BP-based SACs toward promising multifunctional activity. [ABSTRACT FROM AUTHOR]

Inspired by potential application prospects of spintronics and valleytronics, a novel heterobilayer Janus structure is designed by replacing the chalcogenide atomic layers in the original bilayer MoS2. Based on first-principles calculations, it is found that the SMoS/SeMoS structure exhibits a direct band-gap semiconductor and a typical type-II band alignment with longer carrier lifetime. The transition metal (TM) atom represented by V/Cr/Mn can be stably adsorbed on the heterobilayer Janus SMoS/SeMoS sheet and effectively introduce magnetic moments (m). The calculation results demonstrate that the most stable adsorption site of the TM atom is CX(A), and the TM (V/Cr/Mn) adatom modified SMoS/SeMoS system is converted into metal (V-) or half-metal (Cr/Mn-), respectively. Under the coupling of different indirect exchange interactions, the structure exhibits stable intrinsic anti-ferromagnetic interactions for V-SMoS/SeMoS and ferromagnetic ground state for Cr/Mn-SMoS/SeMoS, respectively, and the magnetic transition temperature (T c) reaches a high temperature or even room temperature. Moreover, the robust out-of-plane magnetocrystalline anisotropy energy ensures stable long-range magnetic order. Specifically, the combination of spin injection and strong spin–orbit coupling interaction effectively breaks the time-reversal symmetry, which leads to valley polarization of the system. Based on this, the biaxial strain can effectively regulate the electronic structure, magnetic properties and valley polarization of TM-SMoS/SeMoS nanosheets with double breaking of spatial-inversion and time-reversal symmetry. [ABSTRACT FROM AUTHOR]

It is urgent to develop high-performance anode materials for lithium-ion batteries. In this work, a C3N/C3B p–n heterostructure was systematically investigated by first-principles calculations. The bonding strength of Li in C3N is relatively low (−0.53 eV), whereas the C3N/C3B heterostructure (−1.64 eV to −2.84 eV) can greatly improve the bonding strength without compromising the Li migration capability. The good bonding strength and Li mobility in the C3N/C3B heterostructure are mainly caused by the synergy effect and internal electric field of the p–n heterostructure. Moreover, the electronic structures indicate that the C3N/C3B heterostructure has good conductivity with a tiny bandgap of 0.09 eV. Compared to pristine C3N, the stiffness of the C3N/C3B heterostructure improved significantly (549.35 N m−1). Besides, the C3N/C3B heterostructure presents a high lithium-ion storage capacity (986.61 mA h g−1). The ultrahigh stiffness, good conductivities of electrons and ions, high bonding strength of Li, and high capacity show that the C3N/C3B heterostructure is a prospective anode material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

In recent years, two-dimensional (2D) C-based materials have been intensively studied due to their excellent physicochemical properties. Meanwhile, extensive research has revealed that the electrical properties of layered materials can be tuned by changing the stacking pattern. However, the tuning of ion diffusion properties through stacking remains to be explored. In this work, bilayer C3B with different stackings as a lithium-ion battery anode material is systematically investigated by first-principles calculations. The calculated results show that bilayer C3B has better electronic properties (with a band gap of 0.44 eV to 0.54 eV) and enhanced bonding strength of Li (−2.82 to −3.27 eV) compared to monolayer C3B. Moreover, the intralayer migration barrier of Li can be regulated by stacking. Interestingly, the AB stacked configuration has the lowest migration barrier of 0.100 eV, which is significantly lower than those of other stacking configurations and monolayer C3B. Further studies revealed that the formation of fast ion diffusion channels in the AB stacked configuration is due to the combined effect of layer distance and in-plane charge transfer. These results offer a new strategy for the regulation of ion diffusion properties in 2D van der Waals materials. [ABSTRACT FROM AUTHOR]

Transition-metal chalcogenides (TMCs) are attractive high-capacity anode candidates for secondary batteries, but they suffer from significant challenges including dramatic volume expansion and rapid capacity fading. Despite considerable progress, it was still a big challenge to achieve hundreds of stable cycles with high capacity retention. Herein, we reveal that the copper (Cu) current collector corrosion due to the sulphur (S) species attack leads to serious decay in anode performance in TMC-based batteries, as evidenced by the side-reaction product Cu2S generated via the consumption of S and Cu on the cycled TMC electrode. The electrochemical test and DFT calculations both reveal that the resultant Cu2S increases the resistance at interfaces and reduces the charge transfer, leading to a low capacity and short lifespan. By simply introducing a conductive layer between Cu foil and TMCs, the corrosive influence of Cu is remarkably suppressed, resulting in much enhanced cycling performance. At current densities of 0.5C and 1C, the Cu/2hTi/MoS2 sample delivered a high discharge capacity of 1010 and 740 mA h g−1 after 400 cycles, respectively. This work provides new insights to understand the fundamental mechanism of the electrochemical reactions and strategy to improve the energy storage ability of TMCs. [ABSTRACT FROM AUTHOR]

In monolayer transition metal dichalcogenides, defects, such as chalcogen vacancies, play an important role in determining their properties. Herein, monolayer MoSe2 with varying Se vacancy concentrations is successfully prepared by adjusting the amount of the precursors during the chemical vapor deposition synthesis. The Raman and low‐temperature photoluminescence spectra are systematically studied at varying defect concentrations. Furthermore, it is found that Se vacancies introduce in‐gap electronic states, leading to distinct localized exciton emissions, which can be engineered by controlling the concentration of Se vacancies. Density functional theory calculations indicate that the observed variations in localized exciton emission are attributed to the change of defect level with increasing defect concentration. The results provide insights into the influence of varying Se vacancy concentrations on defect‐induced Raman and PL spectroscopy in MoSe2. [ABSTRACT FROM AUTHOR]

By constructing Zinc‐Blende (ZB)/Wurtzite (WZ) boron nitride (BN) (ZB1‐x/WZx‐BN) superlattices (SLs), their electronic structure and mechanical properties were investigated by first‐principles techniques based on density functional theory. It is found that the band structure is significantly modulated by the ratio of WZ phase in ZB/WZ‐BN SLs. With the increase of WZ ratio, the band gap of SLs decreases and then increases dramatically. More importantly, transformation from type‐I to type‐II band alignment between ZB and WZ can be tuned by adjusting the ratio of WZ to be >0.6. In addition, a universal expression of the band gap is proposed to reveal a nonlinear dependence of the band gap within the structure of SLs as induced by from the interface effect achieved via structural transformation. The elastic constants results revealed that the change of ZB/WZ ratio poses no significant effect on the mechanical properties. The effect of structure modulation on band structure and mechanical properties is significantly important for future engineering of novel semiconductor SLs. The electronic structures of ZB1‐x/WZx‐BN on homojunction interface were systematically investigated with first‐principles calculations. A nonlinear dependence of band gap on the composition of SLs is obtained through the introduction of a higher‐order term expressed as cx3(1‐x) to perfectly describe the interface effect. [ABSTRACT FROM AUTHOR]

To manipulate the electrical and optical properties of ultrathin two-dimensional (2D) layered materials, many approaches including the engineering of strain, doping, defects, and chemical absorption have been developed in recent years. However, the researches on crested substrates, which cause strains and emerging functionalities from the rigid substrate are limited. It shows great potential in improving carrier mobility, promoting charge transfer and charge injection, and decreasing the contact resistance of 2D material devices. Here, recent advances on crested substrates in 2D material-based optoelectronic and photonic devices are reviewed. These developments are classified in three aspects: the generation of crested structure in 2D materials; the strain-induced effect and more effects (plasmonic resonance, charge transfer, hot electron injection, optical effect) due to the crested surface; the state-of-the-art of the performance enhancement in 2D materials optoelectronics and photonics. We also present our perspectives on the physics and potential applications based on the crested structures. [ABSTRACT FROM AUTHOR]

• C 3 N nanoribbons exhibits excellent mechanical properties and good electronic conductivity. • H-passivated C 3 N nanoribbons have a high Li insertion capacity of 708.60 mA h g−1. • C 3 N nanoribbons exhibits significantly enhanced Li binding strength (0.21-2.11 eV) without the sacrifice of Li mobility. The potential of C 3 N nanoribbons used as anode material for lithium-ion batteries has been systematically investigated through first-principles calculations. The results suggest that C 3 N nanoribbons have excellent mechanical properties (stiffness ranging from 286.28 to 412.69 N m−1) and good electronic conductivity (with a bandgap of 0-0.31 eV). Further studies reveal that the H-passivated C 3 N nanoribbons have high Li insertion capacity (708.60 mA h g−1) and significantly enhanced Li binding strength (0.21-2.11 eV) without the sacrifice of Li mobility. The high stiffness, superior cycle performance, good electronic conductivity, and excellent Li migration capability indicate the great potential of C 3 N nanoribbons to be an anode material. The calculated results provide the valuable insights for the development of high-performance C 3 N nanoribbons electrode materials in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

• Predicted three new C 3 N allotropes structures and verified its stability. • Investigated the origin of metallic behavior in C 3 N allotropes. • Revealed the excellent mechanical properties, good electronic conductivity and Li migration capability of C 3 N allotropes. Two-dimensional monolayer C 3 N has attracted much attention in many fields, owing to its unique mechanical, electrical and thermal properties and diverse structure. However, the physical origin of these properties lacks a systematic and clear understanding. In this work, three dynamically stable metallic C 3 N allotropes were computationally investigated. The cohesive energy of all these structures is within 0.09 eV/atom of that of the experimentally reported semi-conductive C 3 N structure. Density-functional theory calculations showed that the metallicity of two-dimensional C 3 N can be attributed to the continuity of the carbon chains, which form channels for passage of free electrons. Furthermore, additional calculations showed that the C 3 N allotropes possess excellent mechanical properties, good electronic conductivity and Li migration capability (wherein the C-C chains provide a good migration channel for lithium ions). These properties make C 3 N a promising candidate for Li-ion battery anode materials. Our findings suggest a physical mechanistic basis for modulating the electrochemical properties of such materials by controlling the arrangement of atoms. The study also provides new ideas for the modulation of the structure and properties of two-dimensional materials and points out a direction for the ongoing development and application of C-N materials and devices. [ABSTRACT FROM AUTHOR]

The possibility of Fe loaded on BP (Fe@BP) as an efficient gas sensor for the detection of toxic gases such as NO2, NO, and CO is studied by the first‐principles calculation, and it is proposed that Fe@BP is an excellent gas‐sensitive material. The adsorption behaviors of gases on Fe@BP were analyzed in terms of adsorption configurations and electronic properties. It is found that all gases adsorbed on Fe@BP exhibit significantly enhanced interactions, and the adsorption intensity is much larger than that of molecules adsorbed on the surface of pure BP. Fe@BP has high selectivity for toxic and ambient gas molecules. In addition, the adsorption strength of NO2 and NO molecules on Fe@BP increases after compression strain is applied (within −3%), while the adsorption strength of CO decreases gradually. After the tensile strain is applied, the adsorption intensity of NO2 and NO is decreased, but that of CO is increased gradually. It is speculated that the strain causes changes in the electronic structure, which affects the adsorption behavior. The adsorption of NO has a stronger strain sensitivity. For these reasons, Fe@BP with high adsorption strength and strain selection is the ideal gas‐sensitive material. [ABSTRACT FROM AUTHOR]

The mechanical properties and electronic structures of TiC and TiN with different doping ratio of vanadium (V) are studied in this work using the first principles calculations. The simulation results show that Ti1−xVxN has lower formation energy than Ti1−xVxC, suggesting higher chemical stability of Ti1−xVxN. Ti0.25V0.75C and TiN show larger hardness than other Ti1−xVxC and Ti1−xVxN compounds. The anisotropic Young's modulus of Ti1−xVxC and Ti1−xVxN models are plotted in 3D surface constructions, and VN exhibited the strongest anisotropy. The uniaxial tensile simulation of Ti1−xVxC and Ti1−xVxN are conducted along [111] direction. The tensile strength of Ti1−xVxN is stronger than Ti1−xVxC. The tensile strength increases with the increasing of V‐doping ratio. Furthermore, the electronic structures of Ti1−xVxC and Ti1−xVxN are estimated. The modeling techniques used in this work and the calculation results are helpful for systematically understanding the properties of Ti1−xVxC and Ti1−xVxN in nanoscale. The mechanical properties and the electronic structures of TiC and TiN with different doping ratio of vanadium (V) are studied in this work using the first principles calculations. The results are helpful for systematically understanding the properties of Ti1−xVxC and Ti1−xVxN in nanoscale. [ABSTRACT FROM AUTHOR]

• MoS 2 monolayer flakes with various shapes have been grown by CVD. • Growth-induced strain affect the MoS 2 monolayers. • Investigated the mechanism of the distinct PL edge on MoS 2 monolayer flakes. Two-dimensional materials such as transitional metal dichalcogenides exhibit unique optical and electrical properties. Here we report on the varying optical properties of CVD grown MoS 2 monolayer flakes with different shapes. In particular, it is observed that the perimeter and the central region of the flakes have non-uniform photoluminescence (PL) energy and intensity. We quantified these effects systematically and propose that thermally induced strain during growth is the origin. The strain relaxation after transfer of the MoS 2 flakes supports this explanation. Detailed investigations of the spatial distribution of the PL energy reveal that depending on the shape of the MoS 2 flakes, the width of the strain field is different. Thus, our results help to elucidate the fundamental mechanisms responsible for the differences in PL and Raman signals between the perimeter region and the center region of monolayer MoS 2 and suggest that the induced strain plays an important role in the growth of monolayer materials. [ABSTRACT FROM AUTHOR]

• The adsorption of CO, O 2 , NO 2 , NO, H 2 S, NH 3 , SO 2 , CH 4 and CH 2 O on 2D Na 3 Bi was researched by DFT. • The electronic properties change dramatically after adsorption. • NO 2 /Na 3 Bi and CH 2 O/Na 3 Bi systems are supposed to exhibit metallic property. 2D Na 3 Bi has attracted significant interests due to its surface properties. The adsorption characteristics of gas molecules on Na 3 Bi monolayer are researched by a first-principles calculation method based on density functional theory. The results show that due to the gas molecular injection, the surface electronic distribution of the 2D Na 3 Bi is reconstructed with adsorption energy of 0.062-2.837 eV and charge transfer of 0.003-1.565, and show the obvious change of electronic and molecular structures. In addition, the band gap has significantly changed, especially when adsorbed by NO 2 and CH 2 O, the system changes into metallicity. Furthermore, there were noticeable orbital hybridization between NO 2 as well as CH 2 O and Na 3 Bi monolayer during adsorption process in DOS. It is possible to detect and identify gas molecules by the novel adsorption properties of 2D Na 3 Bi. This work will provide a theoretical model for the application of Na 3 Bi-based gas sensitive materials in the future. [ABSTRACT FROM AUTHOR]

• The structural stability and temperature effect in allotropes of scandium chalcogenides ScX (X=S, Se and Te) are studied. • The phase transition from hcp structure to β -hcp structure in ScTe is found at finite temperature. • The energy barrier between hcp and β -hcp structure of ScTe suggests that the phase transformation can occur easily. Based on first-principles calculations, the structural stability and temperature effect in ScX (X=S, Se and Te) compounds are studied with three typical structures of B1 (NaCl-type), hcp (NiAs-type) and β -hcp (inverse Li 2 O 2 -type). Their dynamic stability has been verified using phonon mode analysis and molecular dynamics simulations. From the total energy calculations, we find that the most stable ground state structures are B1 for ScS, and hcp for ScSe and ScTe, respectively. Moreover, structural stabilities at finite temperature are studied with the combination of phonon dependent dynamics analysis and first-principles calculations, which reveals a phase transition from hcp to B1 in ScSe around 230 K and a phase transition from hcp to β -hcp in ScTe around 460 K, in accordance with experimental findings. The energy barrier and pathway along the phase transformation from hcp to β -hcp ScTe are also calculated and analyzed by the solid-state nudged elastic band method. [ABSTRACT FROM AUTHOR]

A sulfur vacancy-rich, Sn-doped as well as carbon-coated MoS 2 composite (Vs-SMS@C) is rationally synthesized via a simple hydrothermal method combined with ball-milling reduction, which enhances the sodium storage performance. Benefiting from the 3D fast Na + transport network composed of the defective carbon coating, Mo─S─C bonds, enlarged interlayer spacing, S-vacancies, and lattice distortion in the composite, the Na + storage kinetics is significantly accelerated. As expected, Vs-SMS@C releases an ultrahigh reversible capacity of 1089 mAh g -1 at 0.1 A g -1 , higher than the theoretical capacity. It delivers a satisfactory capacity of 463 mAh g -1 at a high current density of 10 A g -1 , which is the state-of-the-art rate capability compared to other MoS 2 based sodium ion battery anodes to the knowledge. Moreover, a super long-term cycle stability is achieved by Vs-SMS@C, which keeps 91.6% of the initial capacity after 3000 cycles under the current density of 5 A g -1 in the voltage of 0.3-3.0 V. The sodium storage mechanism of Vs-SMS@C is investigated by employing electrochemical methods and ex situ techniques. The synergistic effect between S-vacancies and doped-Sn is evidenced by DFT calculations. This work opens new ideas for seeking excellent metal sulfide anodes., (© 2023 Wiley‐VCH GmbH.)

The rapid industrial development has contributed to worsening global pollution, necessitating the urgent development of highly sensitive, cost-effective, and portable gas sensors. In this work, the adsorption of CO, CO 2 , H 2 S, NH 3 , NO, NO 2 , O 2 , and SO 2 gas molecules on pristine and Cu- and Al-decorated monolayer TiSe 2 has been investigated based on first-principles calculations. First, the results of the phonon spectrum and ab initio molecular dynamics simulations demonstrated that TiSe 2 is dynamically stable. In addition, compared to pristine TiSe 2 (-0.029 to -0.154 eV), the adsorption energy of gas molecules (excluding CO 2 ) significantly decreased after decorated with Cu or Al (-0.212 to -0.977 eV in Cu-decorated TiSe 2 , -0.438 to -2.896 eV in Al-decorated TiSe 2 ). Among them, NH 3 and NO 2 have the lowest adsorption energies in Cu and Al-decorated TiSe 2 , respectively. Further research has shown that the decrease in adsorption energy of gas molecules is mainly due to orbital hybridization and charge transfer between decorated Cu and Al atoms and gas molecules. These findings suggest that TiSe 2 decorated with Cu and Al can effectively improve its sensitivity to NH 3 and NO 2 , respectively, making it promising in gas sensing applications.

It is urgent to develop high-performance anode materials for lithium-ion batteries. In this work, a C 3 N/C 3 B p-n heterostructure was systematically investigated by first-principles calculations. The bonding strength of Li in C 3 N is relatively low (-0.53 eV), whereas the C 3 N/C 3 B heterostructure (-1.64 eV to -2.84 eV) can greatly improve the bonding strength without compromising the Li migration capability. The good bonding strength and Li mobility in the C 3 N/C 3 B heterostructure are mainly caused by the synergy effect and internal electric field of the p-n heterostructure. Moreover, the electronic structures indicate that the C 3 N/C 3 B heterostructure has good conductivity with a tiny bandgap of 0.09 eV. Compared to pristine C 3 N, the stiffness of the C 3 N/C 3 B heterostructure improved significantly (549.35 N m -1 ). Besides, the C 3 N/C 3 B heterostructure presents a high lithium-ion storage capacity (986.61 mA h g -1 ). The ultrahigh stiffness, good conductivities of electrons and ions, high bonding strength of Li, and high capacity show that the C 3 N/C 3 B heterostructure is a prospective anode material for lithium-ion batteries.

Two-dimensional materials (2DMs) that are stacked vertically with a certain twist angle provide new degrees of freedom for designing novel physical properties. Twist-related properties of homogeneous bilayer and heterogeneous bilayer 2DMs, such as excitons and phonons, have been described in many pioneering works. However, twist-related properties of homogeneous trilayer 2DMs have been rarely reported. In this work, trilayer MoS 2 with the twisted angle of 12° by optimized vapor deposition rather than the conventional mechanical stacking method was successfully fabricated. The inversion symmetry of trilayer MoS 2 is changed by twist. Phonons and excitons produced by twist have an enormous influence on the interlayer interaction of trilayer MoS 2 , making trilayer MoS 2 appear to have exotic optical properties. Compared with monolayer MoS 2 , the phonon vibration and photoluminescence intensity of trilayer MoS 2 with one-interlayer-twisted are significantly improved, and the second harmonic generation response in the non-twist region of trilayer MoS 2 is ∼3 times that of monolayer MoS 2 . In addition, interlayer coupling, inversion symmetry, and exciton behavior of the twist region show regional differences. This work provides a new way for designing twist and exploring the influence of twist on the structures of 2DMs with few layers.

In recent years, two-dimensional (2D) C-based materials have been intensively studied due to their excellent physicochemical properties. Meanwhile, extensive research has revealed that the electrical properties of layered materials can be tuned by changing the stacking pattern. However, the tuning of ion diffusion properties through stacking remains to be explored. In this work, bilayer C 3 B with different stackings as a lithium-ion battery anode material is systematically investigated by first-principles calculations. The calculated results show that bilayer C 3 B has better electronic properties (with a band gap of 0.44 eV to 0.54 eV) and enhanced bonding strength of Li (-2.82 to -3.27 eV) compared to monolayer C 3 B. Moreover, the intralayer migration barrier of Li can be regulated by stacking. Interestingly, the AB stacked configuration has the lowest migration barrier of 0.100 eV, which is significantly lower than those of other stacking configurations and monolayer C 3 B. Further studies revealed that the formation of fast ion diffusion channels in the AB stacked configuration is due to the combined effect of layer distance and in-plane charge transfer. These results offer a new strategy for the regulation of ion diffusion properties in 2D van der Waals materials.

Alloying transition metal dichalcogenides (TMDs) with different compositions is demonstrated as an effective way to acquire 2D semiconductors with widely tunable bandgaps. Herein, for the first time, the large-area synthesis of layered HfS 2(1- x ) Se 2 x alloys with fully tunable chemical compositions on sapphire by chemical vapor deposition is reported, greatly expanding and enriching the family of 2D TMDs semiconductors. The configuration and high quality of their crystal structure are confirmed by various characterization techniques, and the bandgap of these alloys can be continually modulated from 2.64 to 1.94 eV with composition variations. Furthermore, prototype HfS 2(1- x ) Se 2 x photodetectors with different Se compositions are fabricated, and the HfSe 2 photodetector manifests the best performance among all the tested HfS 2(1- x ) Se 2 x devices. Remarkably, by introducing a hexagonal boron nitride layer, the performance of the HfSe 2 photodetector is greatly improved, exhibiting a high on/off ratio exceeding 10 5 , an ultrafast response time of about 190 µs, and a high detectivity of 10 12 Jones. This simple and controllable approach opens up a new way to produce high-quality 2D HfS 2(1- x ) Se 2 x layers, which are highly qualified candidates for the next-generation application in high-performance optoelectronics., (© 2018 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this study, rhenium-tungsten mixed particles with different content of rhenium have been prepared by spray-drying method followed by hydrogen reduction. Using such particles, the cathodes have been prepared by powder metallurgy followed by impregnating BaO, CaO, and Al2O3 with 4:1:1 molar ratio. After proper activation, electron emission test is performed in standard parallel-plate diode configuration. The emission results reveal that the Re-W matrix cathode containing 75% rhenium has the highest direct current emission density of 11.67 A/cm2 at 1000 °C. The work function of Re-W matrices has been investigated by density functional theory method in the frame of the generalized gradient approximation (GGA). The theoretical calculation results indicate that the work function of the matrix has limited contribution to the emission current density of Re-W matrix dispenser cathode. The in situ AES, SEM, and XRD were applied and the results reveal that the superior emission property of the 75Re cathode is owing to a plenty of nanoparticles and higher free barium concentration on the cathode surface, which is attributed to the Re3W single phase in 75Re matrix.