Gibbs Free Energy Diagram Research Articles

Ligand engineering regulates the electronic structure of Ni-N-C sites to promote electrocatalytic acetylene semi-hydrogenation

Compared with traditional thermal catalytic hydrogenation technology, electrocatalytic acetylene semi-hydrogenation (EASH) is a green and environmentally friendly method. EASH utilizes renewable electricity under normal temperature and pressure conditions, and uses water as a hydrogen source to electrocatalytically semi-hydrogenate acetylene to ethylene. Ni-based single-atom catalysts (SACs) have shown good application prospects in EASH, but there is still much room for optimization. The axial coordination regulation of the active center is a potential means to improve its activity. In this work, the activity and selectivity of NiN4 SACs with 14 axial ligands (X) for EASH were systematically studied via density functional theory (DFT). First, the binding energy and ab initio molecular dynamics simulation results show that all the NiN4-X can exist stably. Second, the Gibbs free energy diagram shows that the activation and adsorption of C2H2 is the rate-determining step of the reaction. The introduction of the –ONO ligand enhances the activation and adsorption of C2H2 by NiN4, which is beneficial to the occurrence of EASH and inhibits the side reactions of hydrogen evolution. The two parameters ΔG∗CHCH and ΔG∗CH2CH3 can be used as characteristic descriptors to predict the activity and selectivity of EASH. Finally, the catalytic activity mechanism was explained from the perspective of electrons and orbitals, and it was found that the dz2 orbital played a leading role in the axial ligand regulation of C2H2 catalytic activity. This work provides a new method for the development of efficient EASH catalysts.

High throughput MN4-G screening electrocatalyst for highly selective acetylene semi-hydrogenation

The large-scale production of polyethylene in the petrochemical industry requires the effective removal of trace amounts of acetylene impurities. Currently, acetylene is selectively reduced to ethylene via catalytic hydrogenation under high-temperature and high-pressure conditions. However, owing to the harsh reaction conditions of this thermocatalytic method, it requires significant energy and lacks selectivity. Electrocatalytic acetylene semi-hydrogenation (EASH) has emerged as a promising alternative to traditional thermal catalytic hydrogenation. In this study, the density functional theory (DFT) calculations were used to systematically investigate the electrocatalytic activity and selectivity of 25 nitrogen-doped graphene composites containing 3d, 4d, and 5d transition metals (MN4-G) toward EASH, aiming to identify efficient single-atom catalysts (SACs) for EASH reactions. Firstly, the binding, cohesive, and formation energy calculations reveal that all single metal atoms except Mo, Ru, Ag, W Re and Os can be stably immobilized on nitrogen-doped graphene. Secondly, the Gibbs free energy diagram exhibits that Cu and Ni SACs promote EASH and inhibit the hydrogen evolution side reaction. Moreover, the d-band center of the metal site and the acetylene adsorption energy can be used as characteristic descriptors to predict the EASH selectivity of the catalyst. Finally, the mechanism of catalytic activity is described from the perspective of electrons and orbitals, revealing the coupling between dz2 and C2H4-πz∗ orbitals plays a vital role in ethylene desorption. This study provides an in-depth understanding of the mechanism of high-efficiency EASH catalysts at the electronic orbital level.

Optimization of Electrochemical Reduction of Biomass Derived 5-Hydroxymethylfurfural (HMF): A Volcano Plot and Bimetallic Catalysts.

2,5-bis(hydroxymethyl)furan (BHMF) derived from 5-Hydroxymethylfurfural (HMF) through a hydrogenation process has extensive applications in the production of resins, polymers, and artificial fibers. However, screening out the candidate and then modulating the active site to optimize the catalyst for high yield of BHMF are currently insufficient. In this study, Gibbs free energy diagrams of the reduction of HMF on 13 metals were presented, along with the identification of the rate-determining step (RDS) with the highest reaction barrier for each metal. We attempted to construct a volcano plot for HMFRR reaction. Additionally, a strategy was proposed to adjust the reaction barriers of RDS by combining two appropriate metals. Further experiments confirmed that Pb with the lowest energy barrier exhibited the highest HMF conversion (BHMF selectivity) among single metals. The modified catalyst by doping Ag on Pb, further boosted the HMF conversion (BHMF selectivity) from 42.1% (59.4%) to 80.8% (80.9%), respectively. These results provide an approach to rationally design and construct the catalyst system for efficient conversion of HMF.

First-principles study on MoSSe/ GaTe van der Waals heterostructures: A promising water-splitting photocatalyst

Photocatalytic water splitting using semiconductor electrocatalysts in photoelectrochemical cells is an appealing approach to converting sunlight and water into clean and renewable hydrogen fuel. MoSSe/GaTe der Waals heterojunctions has recently been suggested as a promising photocatalyst for water splitting. Depending on the stacking mode, the two type MoSSe/GaTe heterojunctions have moderate band gaps of 1.081 eV and 1.307 eV, significant visible absorption coefficients, and band-edge positions spanning the redox potential of water. Bader charge and differential charge density analyses show that the GaTe layer loses electrons and the MoSSe monolayer gains electrons, resulting in a built-in electric field pointing from the GaTe layer to the MoSSe layer. Moreover, the Gibbs free energy diagram indicates that solar energy can effectively drive water splitting on MoSSe/GaTe junction. The influence of the bi-axial strain and pH value of water are discussed. Therefore, the MoSSe/GaTe heterostructures are promising for applications in photocatalytic water decomposition.

Unraveling the two-stage precipitation mechanism in a hierarchical-structured fcc/L21 high-entropy alloy: Experiments and analytical modeling

Understanding the phase stability and precipitation mechanisms is crucial for engineering multiphase nanostructured alloys with optimal mechanical properties. In this work, we studied the formation and temporal evolution of nanoprecipitates and their effect on mechanical properties of an fcc/L21 eutectic high-entropy alloy through a combination of experiments and analytical modeling. Aging the alloy at 1023 K results in the precipitation of coherent L12 nanoparticles in the fcc phase and coherent bcc nanoparticles in the L21 phase, leading to the formation of an fcc/L12 + L21/bcc hierarchical structure. Notably, the scanning transmission electron microscopy (STEM) results reveal that the precipitation in both the fcc and L21 phases is not through a one-step nucleation, but a two-stage transformation consisting of an initial chemical separation via spinodal decomposition and subsequent structural ordering/disordering. The Gibbs free energy diagrams of the fcc and L21 phases were modeled through numerical techniques, and the spinodal decomposition regions of the two systems at different temperatures were calculated. Based on the modeling results, we discussed the phase stability and thermodynamics of spinodal decomposition of the two phases. In addition, the formation of hierarchical structure substantially enhances the strength of the alloy. Modeling of the strengthening mechanisms reveals that the order strengthening of L12 nanoparticles plays a major role in enhancing the yield strength of the alloy, whereas the contribution from the bcc nanoparticles can be negligible. Our findings provide insights into the phase stability, precipitation and strengthening mechanisms of hierarchical-structured alloys.

Tuning the Bonding Behavior of d‐p Orbitals to Enhance Oxygen Reduction through Push–Pull Electronic Effects

AbstractThe regulation of electronic structure is intricately linked to the intrinsic activity of oxygen reduction. Herein, a strategy for electronic structure modulation induced by bimetallic push–pull electronic effects in dual‐atom catalysts (Fe,Ni/N‐C@NG) is developed. Experiments and theoretical analysis reveal that Fe sites exhibit favorable bonding behaviors (Fe–O: dxz‐p, dyz‐p, and dz2‐p) and spin configurations, which can enable rapid desorption of *OH and thus enhance the intrinsic activity of oxygen reduction. In situ monitoring techniques and Gibbs free energy diagram further demonstrate that the adjacent Ni could serve as second active center to participate in oxygen reduction. The Fe,Ni/N‐C@NG exhibits enhanced oxygen reduction reaction activity and excellent stability. Meanwhile, the assembled Zn–air battery maintains stability for over 300 h with a small voltage gap. This study provides multiple insights into the orbital scale laws of oxygen reduction.

Rh4 cluster supported on the In2O3(111) surface for enhancing the turnover frequency of CO2 hydrogenation to methanol: The application of energetic span model

The turnover frequency of CO2 hydrogenation to methanol on the surface of Rh4 cluster supported In2O3(111) is investigated using the first-principles calculation. The Rh4 cluster and H2 promote oxygen vacancy formation, which facilitates the interaction between the Rh4 cluster and the In2O3(111) carrier and improves the stability of catalyst. The adsorption behavior of CO2 and H2 on catalyst is predicted by electrostatic potential and Fukui(−) index. The loading of Rh4 cluster promotes the adsorption of CO2 and allows easier dissociation of H2 compared to the In2O3(111)_D surface. Afterwards, Gibbs free energy diagrams of three hydrogenation pathways are established and the turnover frequencies of all possible routes are calculated based on the energetic span model. The results reveal that the HCOO pathway is regarded as the optimum hydrogenation mechanism due to its greatest turnover frequency (3.02 × 10−5 s−1), higher than that of In2O3(111)_D and other reported catalysts. The specific process is CO2(g) + 6H → HCOO* + 5H → HCOOH* + 4H → H2COOH* + 3H → H2CO* + 2H + H2O(g) → H2COH* + H + H2O(g) → CH3OH(g) + H2O(g), while the RWGS pathway and by-products are effectively inhibited, thus enhancing the selectivity of methanol. The improvement in catalytic activity may result from the loaded Rh4 cluster facilitating the adsorption of CO2 and the dissociation of H2.

Theoretical Analysis of Metals Supported on Tungsten Oxide Nanowires (W18O49) for Water Dissociation Reaction

AbstractPt is the cause of the high total cost of fuel cells and electrolyzers, leading to difficult commercialization. Here, various types of metal atoms, i.e., Pt, Pd, Ni, Ir, Ag, and Rh, suitable for catalysts are used and supported by W18O49 nanowires for oxygen evolution reaction (OER) by the density functional theory (DFT) method. Four adsorbate molecules involved in OER were tested on adsorption energy: OH, O, OOH, and OO. Although the adsorption energy of these adsorbate molecules indicates that W18O49 has low adsorption energy, the Gibbs free energy diagram demonstrates that W18O49 has high OER reaction energy. Pt, Pd, Ni, and Rh have the lowest Gibbs energy to initiate the reaction and reasonable Gibbs free energy for other OER reactions. Bimetallic or trimetallic active sites can be developed along with selecting other metals with Pt, Pd, Rh, and Ni to reduce the Gibbs free energy difference for the decomposition of OH to O and OOH to H2O. Ag metal can also be applied as a second or third metal because Ag exhibits a relatively low Gibbs free energy difference in the O to OOH step. A selectivity study of each step on bimetallic and trimetallic active sites needs to be performed.

Simulations and Experiments on the Microstructure and Property Evolution of In Situ TiC+Al3Ti-Reinforced Aluminum Coatings on AZ91D Magnesium Alloy

With the development of computational thermodynamics, it is possible to design a material based on its simulated microstructure and properties before practical operations. In order to improve the surface properties of AZ91D magnesium alloy, Jmatpro was used in this study to design an alloy system with in situ TiC+AlTi3-reinforced aluminum coatings. The Gibbs free energy, hardness, and phase diagrams of aluminum coatings with different ratios of Ti to B4C were simulated. According to the simulation results, TiB2, TiC, Al3Ti_DO22, and Al4C3 were formed in the coating while TiB2, TiC, Al3Ti_DO22, Al4C3, and Al3Mg2 were formed in the transition zone between the base metal and the coating. Based on the simulation results, different amounts of Ti were used with B4C (the ratios were 3:1, 4:1, 5:1, and 6:1) to fabricate TiC+Al3Ti reinforced aluminum coatings on AZ91D magnesium alloy via laser cladding. The microstructure and phase composition of the coating were studied using scanning electron microscopy (SEM) incorporated with energy- dispersive spectrometry (EDS) and X-ray diffraction (XRD). The results indicated that intermetallic phases, such as AlTi3(C, N)0.6, AlMg, Al3Mg2, Al3Ti, and TiC were formed in the coatings. As the Ti content increased, the content of Al3Ti increased and the content of TiC decreased in the coatings, which is consistent with the simulation results. The average hardness of the coatings was approximately four to five times that of the magnesium alloy substrate, and the corrosion current density of the coatings was around 2.5 × 10−6, which is two orders of magnitude lower than that of AZ91D magnesium alloy.

New insight into efficient photocatalytic CO2 reduction without any sacrifice agent over the novel hierarchical structured SiOC whisker aerogel

Photoreduction of CO2 to valuable fuels provides a promising strategy for managing the global carbon balance using renewable solar energy, yet the design of active, cost-effective, highly selective, and stable CO2 reduction photocatalysts remains a big challenge. Herein, we report a novel SiOC aerogel photocatalyst synthesized by a simple one-step sol-gel process, combined with the supercritical drying technique and heat treatment processes. The resulting SiOC aerogel exhibits a large BET specific area with typical hierarchical structures, which is responsible for the enhanced photocatalytic activity. In addition, the formation mechanism of the SiOC whisker aerogel is revealed in this study. The optimized SiOC aerogel exhibits CH4 and CO evolution activity of 5.8 and 20.5 μmol/g under simulated sunlight irradiation, respectively, without any additional co-catalyst or sacrificial agent, which is 6.4 and 3.9 times higher than those of the pristine SiC aerogel. The density functional theory (DFT) calculation confirms that the resulting SiOC aerogel can effectively adsorb and activate CO2 and H2O molecules on the catalyst surface. The Gibbs free energy diagram further verifies the superior performance of the resulting SiOC aerogel over the pristine SiC and SiO2 cluster via the rate-determining step calculations. The high efficiency of CO2 reduction can be attributed to the structural merits and the electronic structures modulation, which greatly achieves fast separation and transfer of charge carriers. The work paves an insight into the rational design of photocatalysts toward simultaneously facilitating carrier separation and CO2 activation from aerogel-based porous materials.

A new carbon allotrope: Biphenylene as promising anode materials for Li-ion and Li[sbnd]O2 batteries

Using first-principles computational approaches, we investigate a new carbon allotrope, biphenylene, composed of tetragonal, hexagonal, and octagonal carbon rings as a promising material for Li-ion and LiO2 batteries. We find the Li/C ratio is <1/6 for the single-layer biphenylene which is similar to that of graphene. However, it can reach to lithium composition of Li1C6, Li1C4.5, Li1C4, Li1C3.75, and Li1C3 for bi-, tri-, tetra-, penta-layer, and bulk biphenylene, respectively. It is also found that Li is very mobile on both single-layer and bi-layer biphenylene based on the calculation results of the interaction between Li and substrate and Li diffusion. In addition, we also elucidate the electrochemical performance via the discharge−charge mechanism using Li/biphenylene as electrocatalyst materials of LiO2 battery. Gibbs free energy diagram of the discharge-charge mechanism is illustrated to examine the electrochemical performance. Our results reveal that biphenylene network can be a promising and low-cost catalyst for both Li-ion and LiO2 batteries.

Strong Spin Polarization Effect of Atomically Dispersed Metal Site Boosts the Selective Photocatalytic Nitrobenzene Hydrogenation to Aniline over Graphitic Carbon Nitride.

Atomically dispersed catalysts (ADCs) with a well-defined structure are theoretically desirable for a high-selectivity photocatalytic reaction. However, achieving high product selectivity remains a practical challenge for ADCs-based photocatalysts. Herein, we reveal a spin polarization effect on achieving high product selectivity (95.0%) toward the photocatalytic nitrobenzene (PhNO2) hydrogenation to aniline (PhNH2) on atomically dispersed Fe site-loaded graphitic carbon nitride (Fe/g-C3N4). In combination with the Gibbs free energy diagram and electronic structure analysis, the origin of the photocatalytic performance is attributed not only to the strong metal-support interaction between the Fe site and g-C3N4, but more importantly to the strong spin polarization effect that promotes the potential-determining step (PDS) of *PhNO to *PhNOH. This work could be helpful for the design of ADCs-based photocatalysts in view of the spin polarization effect.

Boron-embedded C3N nanosheets as efficient electrocatalysts for reduction of nitric oxide

The electrochemical reduction of nitric oxide (NO) is among the most efficient techniques for converting this poisonous gas into valuable compounds. This paper investigates the potential of boron (B)-doped C3N nanosheets for the catalytic reduction of NO molecules using density functional theory calculations. To achieve this goal, two unique B-doped C3N monolayers are investigated, namely, those in which the B atom is substituted with either a carbon (labeled as BC) or a nitrogen atom (labeled as BN). The findings reveal that the NO molecule might be sufficiently activated over both BC and BN electrocatalysts, with the successive reduction process producing NH3 at low coverages and N2 at high coverages. According to the Gibbs free energy diagrams, the BC nanosheet displays outstanding catalytic performance for NO reduction at normal temperature with no limiting potential. The strong coupling of the ∗HNO and NO species may result in the spontaneous formation of N2 at ambient temperature. The findings of this work might be used to develop metal-free electrocatalysts for removing hazardous NO molecules from the environment.

Effects of functional groups in iron porphyrin on the mechanism and activity of oxygen reduction reaction.

The activity of the oxygen reduction reaction (ORR) on the cathode is one of the dominant factors in the performance of proton exchange membrane fuel cells. Iron porphyrin has low cost, environmental benignity, and maximum efficiency of metal usage. Therefore, this material can be a promising single-atomic metal dispersion catalyst for fuel cell cathodes. The variation of functional groups was proven to effectively modify the activity of the ORR on the iron porphyrin. However, the influences of functional groups on the mechanisms of the ORR remain ambiguous. This work paid attention to the substitution of carboxyl (-COOH), methyl (-CH3), and amino (-NH2) functional groups at the meso positions of the porphyrin ring. By using van der Waals density functional theory (vdW-DF) calculations, we found that the ORR mechanisms can follow the associative and dissociative pathways, respectively. The Gibbs free energy diagrams revealed that the rate-limiting step occurs at the second hydrogenation step for the first pathway and the O2 dissociation step for the second pathway for all considered functional groups. The thermodynamic energy barrier at the rate-limiting step was found to be in the following order: porphyrin-(CH3)4 < porphyrin-(NH2)4 < original porphyrin < porphyrin-(COOH)4 for the associative mechanism and porphyrin-(NH2)4 < porphyrin-(CH3)4 < porphyrin-(COOH)4 < original porphyrin for the dissociative pathway. The findings suggested that porphyrin-(CH3)4 and porphyrin-(NH2)4 should be the best choices among the considered substrates for the oxygen reduction reaction. Furthermore, the interaction between the ORR intermediates and the substrates was attributed to the resonance of the d z 2 , d xz , and d yz components of the Fe d orbital and the C and N p orbitals of the substrates with the p orbitals of the oxygen atoms in the intermediates. Finally, the nature of the interaction between the adsorbent and adsorbate was charge transfer.

Theoretical study on the mechanism of water oxidation catalyzed by a mononuclear copper complex: important roles of a redox non-innocent ligand and HPO4 2- anion.

The water oxidation reaction is the bottleneck problem of the artificial photosynthetic system. In this work, the mechanism of water oxidation catalyzed by a mononuclear copper complex in alkaline conditions was studied by density functional calculations. Firstly, a water molecule coordinating with the copper center of the complex (Cuii, 1) generates Cuii-H2O (2). 2 undergoes two proton-coupled electron transfer processes to produce intermediate (4). The oxidation process occurs mainly on the ligand moiety, and 4 (˙L-Cuii-O˙) can be described as a Cuii center interacting with a ligand radical antiferromagnetically and an oxyl radical ferromagnetically. 4 is the active species that can trigger O-O bond formation via the water nucleophilic attack mechanism. This process occurs in a step-wise manner. The attacking water transfers one of the protons to the HPO4 2- coupled with an electron transfer to the ligand radical, which generates a transient OH˙ interacting with the oxyl radical and H2PO4 -. Then the O-O bond is formed through the direct coupling of the oxo radical and the OH radical. The triplet di-oxygen could be released after two oxidation processes. According to the Gibbs free energy diagram, the O-O bond formation was suggested to be the rate-limiting step with a calculated total barrier of 19.5 kcal mol-1. More importantly, the copper complex catalyzing water oxidation with the help of a redox non-innocent ligand and HPO4 2- was emphasized.

The role of coverage effects on the structure–sensitivity of formic acid electrooxidation on Pd surfaces

Direct formic acid (FA) fuel cells (DFAFCs) with Pd anode catalysts are promising for small portable applications. During the electrooxidation of formic acid (FAO), CO accumulates on the Pd electrocatalyst, thereby decreasing its performance. In this work, we use density functional theory (DFT; RPBE) to elucidate the significance of coverage effects on the structure–sensitivity of FAO over four low–index Pd surfaces: Pd(111), Pd(100), Pd(110), and Pd(211). We construct coverage–dependent Gibbs free energy diagrams and in agreement with experiment, predict that Pd(100) and Pd(211) are the most active surfaces. Additionally, we find that the presence of CO spectator species can alter the preferred electrooxidation pathway under different applied potentials. Such pathway transitions appear to be critical for rationalizing experimental trends regarding electrocatalytic activity and are only captured when coverage effects are accounted for. Insights derived from this work may facilitate the design of improved FAO electrocatalysts.

Highly Strong Interaction between Fe/Fe3C Nanoparticles and N‐Doped Carbon toward Enhanced Oxygen Reduction Reaction Performance

AbstractTransition metal compounds anchored on N‐doped carbon (NC) show intrinsic activity and stability for oxygen reduction reaction (ORR). However, the interaction between the transition metal compounds and NC still needs to be strengthened for electron transfer at the compounds/carbon interface. Herein, Fe/Fe3C hybrid nanoparticles encapsulated into N‐doped carbon (Fe@NC) are used as high‐performance ORR catalysts. Benefiting from the strong interaction at Fe/Fe3C nanoparticles/NC interface, the electrons can transfer from Fe/Fe3C hybrid nanoparticles to NC, redistributing the electron density of active sites and promoting the ORR process. The as‐synthesized Fe@NC exhibits outstanding ORR catalytic activity with an onset potential of 1.01 V and a half‐wave potential of 0.92 V in alkaline media. It also shows prominent cycling stability and tolerance to methanol crossover, superior to Pt/C catalyst. The theoretical analysis reveals that the Fe nanoparticles have regulated the electron distributions at the heterojunction interface. The Gibbs free energy diagrams for ORR illustrate that the rate‐determining step is the conversion of OH* to OH−. In situ Raman spectra give evidence of O‐containing intermediates to prove the ORR process.

Enhanced OER Performance by Cu Substituted Spinel Cobalt Oxide

Cobaltite spinel oxides (CuCo2O4), which show electrocatalytic activity for oxygen evolution reaction (OER), are readily synthesized using a facile hydrothermal method, with a stationary ratio, uniform flower-like mesopores morphology, and high crystallinity. We have carried out first-principles calculations on the mechanism of the reaction pathway and the Gibbs free energy diagram of CuCo2O4 structures using density functional theory and purely confirmed by experimental results. This catalyst performed an outstanding OER performance with an overpotential 230 mV at 10 mA cm−2 in 1 M KOH, which was close to IrO2 with an overpotential 190 mV at 10 mA cm−2. This work provides a facile method for electrocatalytic oxygen production with enhanced conductivity and enhanced OER by replacing cobalt with copper.Graphical Abstract

Control of Large‐Scale Single‐Phase Ni Silicide Formation from Reactive Multilayers

The Ni/Si reactive multilayer (RML) is full of application potentials including reactive joining, igniters, and power sources. Here, the Ni/Si RMLs with atomic ratios of Ni and Si (2:1, 1:1, and 1:2) are studied, where the bilayer thickness and the total thickness are controlled to be 53 nm and 2 μm, respectively. After laser ignition, a rapid explosive reaction is observed where there are two self‐propagation wavefronts and their velocities reach 7.20 and 11.93 m s−1. The uniform, small grains, and single‐phase Ni silicides are obtained and controlled by tuning growth parameters. From the understanding of the Gibbs free energy diagram, the first wavefront comes from the solid‐state amorphization reaction between the Ni and a‐Si. The formation of the final Ni silicide causes the second wavefront. The entire reaction is described by a transient heat transfer model. It proposes a key parameter called heat loss rate, which explains the importance of RML thickness and the thermal diffusivity of the substrate. It allows to accurately control the reaction rate, which masters the final silicide phase. Thus, the oxidation of samples downgrades the reliability as the self‐propagation velocity of the two wavefronts dropped to 1.34 and 1.91 m s−1 in samples after 200 h of oxidation.

Thermodynamic mechanism of phase formation for W-Mo-Cu composite by electric field sintering

Since diffusion alloying and metallurgical bonding interfaces have been confirmed to be existed in W-Mo-Cu composite, the thermodynamic mechanism of phase formation is unclear yet. This paper aims at constructing the Gibbs free-energy change diagram for W-Mo-Cu ternary system and revealing the thermodynamic mechanism of the direct alloying among W, Mo and Cu which is not yet clear. The content combines the analysis of experimental results and calculated results based on Miedema's model. The large current electric field induces field emission and provides sufficient energy to overcome thermodynamic barriers and helps the atom diffusion at a relatively low temperature. The high-resolution electron microstructures show that new crystallite phases of (Mo, W), (Mo, Cu), (W, Cu), and amorphous phase (Mo, W) are formed in large current electric field sintering. Meanwhile, the Gibbs free-energy change diagram for W-Mo-Cu system shows that Mo effectively reduces the value of free-energy change, and when Mo content or sintering temperature is as high as possible, Gibbs free-energy change is as small as possible. Additionally, Gibbs free-energy change diagrams for W-Mo, W-Cu and Mo-Cu binary systems are also constructed during the derivation, and the results show that the crystalline and amorphous phases of (Mo, W) are the most easily to be formed, followed by that of (Mo, W) and finally that of (W, Cu).