阅读说明：本技术 一种磷化钼基多晶块体及其制备方法与应用 (Molybdenum phosphide-based polycrystalline block and preparation method and application thereof ) 是由 柳伟 雷雨竹 何大平 唐新峰 于 2020-04-28 设计创作，主要内容包括：本发明公开了一种磷化钼基多晶块体及其制备方法与应用,所述方法包括：以单质为原料,按MoP-(1-y)或者Mo-(1-x)A-(x)P-(1-y)B-(y),化学计量比进行称量和混合均匀得到反应物；其中A为Mo晶格位置的掺杂元素,包括Nb、Fe、Co、Ni元素中的一种或多种,B为P晶格位置的掺杂元素,包括S、Se、Te元素中的一种或多种,x和y为掺杂元素的含量,x＝0～0.06,y＝0～0.07；然后在真空条件或惰性条件下经固相反应得到多晶粉状产物,再经加压烧结即得。本发明从单质原料出发经固相反应和加压烧结两步直接制备,无副产物,设备和流程简单、环保、成本低,可直接用作电催化析氢和析氧的工作电极,无需后续处理。(The invention discloses a molybdenum phosphide-based polycrystalline block and a preparation method and application thereof, wherein the method comprises the following steps: using simple substance as raw material according to MoP 1‑y Or Mo 1‑x A x P 1‑y B y Weighing and uniformly mixing the components according to the stoichiometric ratio to obtain a reactant; a is a doping element at a Mo crystal lattice position and comprises one or more of Nb, Fe, Co and Ni elements, B is a doping element at a P crystal lattice position and comprises one or more of S, Se and Te elements, x and y are the content of the doping element, x is 0-0.06, and y is 0-0.07; then obtaining a polycrystalline powder product through solid phase reaction under the vacuum condition or the inert condition, and then obtaining the product through pressure sintering. The invention directly prepares the product by two steps of solid-phase reaction and pressure sintering from simple substance raw materials, has no by-product, simple equipment and flow, environmental protection and finished productThe electrode has low cost, can be directly used as a working electrode for electrocatalytic hydrogen and oxygen evolution, and does not need subsequent treatment.)

1. A method for preparing a molybdenum phosphide-based polycrystalline block, characterized by comprising:

step 1, using simple substance as raw material according to MoP_1-yOr Mo_1-xA_xP_1-yB_yStoichiometric ratio of the components anduniformly mixing to obtain a reactant; a is a doping element at a Mo crystal lattice position and comprises one or more of Nb, Fe, Co and Ni elements, B is a doping element at a P crystal lattice position and comprises one or more of S, Se and Te elements, x and y are the molar contents of the doping elements, x is 0-0.06, and y is 0-0.07;

step 2, carrying out solid-phase reaction on the reactants under vacuum condition or inert condition to obtain Mo_1-xA_xP_1-yB_yA polycrystalline powder product;

step 3, adding Mo_1-xA_xP_1-yB_yThe polycrystalline powder product is pressed and sintered to obtain Mo_1-xA_xP_1-yB_yA polycrystalline bulk material.

2. The method according to claim 1, wherein the simple substance is powder, and the reactant is powder or pressed into an ingot.

3. The method of preparing a molybdenum phosphide-based polycrystalline block according to claim 1, wherein the inert condition is a sealed vessel filled with an inert gas comprising H₂、Ar。

4. The method of preparing a molybdenum phosphide-based polycrystalline block according to claim 1, wherein the temperature of the solid-phase reaction is 700 ℃ to 800 ℃ and the time of the solid-phase reaction is 40 hours to 55 hours.

5. The method of preparing a molybdenum phosphide-based polycrystalline block according to claim 1, wherein the pressure sintering is selected from hot-press sintering and plasma sintering.

6. The method of preparing a molybdenum phosphide-based polycrystalline block according to claim 1, wherein the pressure sintering process comprises: the sintering temperature is 850-950 ℃, the sintering pressure is 40-80 MPa, and the sintering time is 10-60 min.

7. A molybdenum phosphide-based polycrystalline block prepared by the method according to any one of claims 1 to 6.

8. Use of the molybdenum phosphide-based polycrystalline mass of claim 7 as a self-supporting working electrode for electrocatalytic hydrogen and oxygen evolution.

Technical Field

The invention relates to the technical field of electro-catalytic hydrogen evolution in water electrolysis and chlor-alkali industry, in particular to a molybdenum phosphide-based polycrystalline block and a preparation method and application thereof.

Background

The hydrogen energy has the obvious advantages of cleanness, zero emission, high combustion heat value and the like, the energy density of the hydrogen energy is up to 142500KJ/mol, which is 3 times of the energy density (46100KJ/mol) of gasoline, and the hydrogen energy is a next-generation novel energy. Hydrogen is an extremely important industrial raw material, has wide application in the fields of petrochemical industry, electronic industry, metallurgical industry, food processing, new energy automobiles, aerospace, medical treatment and the like, and has extremely wide application. At present, the industrial production of hydrogen mainly comprises the modes of hydrogen production by reforming fossil raw materials, hydrogen production by catalytic thermal decomposition of methane/methanol, hydrogen production by biomass, hydrogen production by water electrolysis and the like. The hydrogen production by reforming fossil raw materials and the hydrogen production by catalytic thermal decomposition of methane/methanol are main modes for large-scale hydrogen production, and have the disadvantages of consuming the fossil raw materials and discharging greenhouse gas CO₂(ii) a The efficiency of biomass hydrogen production is low. In contrast, the electrolyzed water can not only produce hydrogen but also produce oxygen, and produce high-purity hydrogen and oxygen with important purposes, thereby being a preparation method which is environment-friendly and has both efficiency and cost; this process currently produces commercially 5% high purity hydrogen. However, the current industrial production of hydrogen and oxygen by electrolysis of water relies on expensive and extremely low earth crust reserves of precious metals (such as Pt, Ru, Ir, etc.) as catalysts. Therefore, the development of high-efficiency non-noble metal hydrogen and oxygen evolution catalysts is of great significance to the development of the electrolytic aquaculture industry.

The development of non-noble metal hydrogen and oxygen evolution catalysts is an important topic of electrocatalytic research in recent years, with one of the important goals being to obtain catalysts with low overpotentials. Current Pt/C noble metals and RuO₂the/C noble metal is a commercial hydrogen evolution catalyst and an oxygen evolution catalyst respectively, and the current density of the catalysts is 10mAcm^-2The overpotential is 50meV and 300meV respectively. In order to improve the catalytic performance of electrochemical catalysts, researchers commonly adopt a chemical synthesis method based on hydrothermal synthesis to construct a catalyst with a nano structure, and the purpose of the method is to increase the surface area, expose more electrocatalytic active sites and effectively reduce the overpotential of hydrogen and oxygen evolution catalysts. The hexagonal phase MoP material is an important non-noble metal electrochemical hydrogen and oxygen evolution catalyst. At present, MoP worksThe method is used for preparing the nano-structure MoP and the electrocatalytic performance of the nano-structure MoP as an electrocatalytic material, but no report that a MoP block is directly adopted as the electrocatalytic material exists. For example, chinese invention patent CN104988536B discloses a method for preparing a high performance molybdenum-based hydrogen evolution electrode from a phosphomolybdate precursor, which comprises cleaning the surface of a foam nickel substrate, growing a molybdate nano precursor on the surface of the foam nickel in situ by using molybdate as a reactant, hydrothermal synthesis and high-temperature heat treatment in a reducing atmosphere, and finally growing the molybdate nano precursor on H₂Carrying out high-temperature phosphating treatment on a molybdate precursor in a reducing atmosphere by taking phosphite, elemental phosphorus and the like as phosphorus sources to finally prepare a nanostructured high-performance molybdenum-based hydrogen evolution electrode; the high-conductivity foam nickel matrix is used as a working electrode for hydrogen evolution and oxygen evolution reactions. For example, the chinese patent application CN107999105A discloses a "method for preparing a molybdenum phosphide hydrogen evolution catalyst with a rod-like porous morphology structure", which uses soluble ammonium molybdate and ammonium dihydrogen phosphate as starting materials and absorbent cotton as a soft template, and obtains a molybdenum phosphide precursor through drying and high-temperature treatment, and finally obtains the molybdenum phosphide hydrogen evolution catalyst with a rod-like porous morphology structure through high-temperature reduction treatment; the molybdenum phosphide hydrogen evolution catalyst prepared by the method is powder, and a conductive adhesive is needed to disperse MoP on a high-conductivity nickel substrate, graphite carbon and other working electrodes for hydrogen evolution and oxygen evolution reaction.

The preparation of the MoP material with a specific micro-nano structure by the chemical synthesis method mainly comprises the steps of preparing a molybdenum oxide/molybdenum salt precursor through a solvothermal reaction, and then performing a high-temperature phosphating reaction in a reducing atmosphere to prepare the MoP-based material: the synthesis process involves multi-step reactions such as solvothermal reaction, cleaning, drying, high-temperature heat treatment in reducing atmosphere, phosphating reaction and the like, the working procedure is complex, and the controllable preparation difficulty is high; meanwhile, H is required for high-temperature phosphating treatment₂、PH₃And elemental phosphorus sources and the like, and toxic wastewater and waste residues are discharged and NH is discharged in the synthesis process₃、PH₃、H₂And the like incompletely reacted toxic/hazardous gases. Moreover, the prepared MoP material is not grown on the surface of the working electrode in situ, and a conductive adhesive is used for realizing MoP andthe combination of the working electrodes can be used for the hydrogen and oxygen evolution reaction.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a molybdenum phosphide-based polycrystalline block and a preparation method and application thereof. Moreover, the molybdenum phosphide-based polycrystalline block prepared by the process has excellent electrocatalytic properties: the current density is 10mAcm^-2Overpotentials in the hydrogen evolution process and the oxygen evolution process respectively reach 205mV and 213 mV; in addition, the compact molybdenum phosphide-based polycrystalline block has high conductivity equivalent to working electrodes of metallic nickel, carbon materials and the like, can be directly used as a self-supporting working electrode for electrocatalytic hydrogen and oxygen evolution, and does not need subsequent treatment.

The invention is realized by the following steps:

an object of the present invention is to provide a method for producing a molybdenum phosphide-based polycrystalline bulk, comprising:

step 1, using simple substance as raw material according to MoP_1-yOr Mo_1-xA_xP_1-yB_yWeighing and uniformly mixing the components according to the stoichiometric ratio to obtain a reactant; a is a doping element at a Mo crystal lattice position and comprises one or more of Nb, Fe, Co and Ni elements, B is a doping element at a P crystal lattice position and comprises one or more of S, Se and Te elements, x and y are the content of the doping element, x is 0-0.06, and y is 0-0.07;

step 2, carrying out solid-phase reaction on the reactants under vacuum condition or inert condition to obtain Mo_1-xA_xP_1-yB_yA polycrystalline powder product;

step 3, adding Mo_1-xA_xP_1-yB_yThe polycrystalline powder product is pressed and sintered to obtain Mo_1-xA_xP_1-yB_yA polycrystalline bulk material.

The above-mentioned reasons are that x is controlled to 0 to 0.06 and y is controlled to 0 to 0.07In order not to affect the intrinsic electrocatalytic properties of the MoP and to obtain a highly dense sintered mass. As shown in the doping amount and the density variation trend in Table 1, if x is greater than 0.06 and y is greater than 0.07, Mo is present_1-xA_xP_1-yB_yThe density and conductivity of the polycrystalline block may be too low, which affects the ability of the polycrystalline block to serve as an in-situ working electrode for electrocatalytic reaction.

Preferably, the inert condition is a sealed container filled with inert gas or a vacuum environment, and the inert gas comprises H₂And Ar. The inert gas can be in a small amount, the introduction amount of the inert gas is not limited, and the inert gas is mainly used for avoiding the material from being oxidized or nitrided under the high-temperature condition.

Preferably, the temperature of the solid phase reaction is 700 ℃ to 800 ℃ (more preferably 700 ℃ to 750 ℃); the solid phase reaction time is 40-55 h. The range of the solid-phase reaction temperature and the solid-phase reaction time is set so that the reaction between the constituent elements proceeds smoothly. As described in experimental example 2, if the temperature of the solid phase reaction is less than 700 ℃, the reaction between the constituent elements is difficult to completely proceed.

Preferably, the pressure sintering is selected from hot-press sintering or plasma sintering.

Preferably, the pressure sintering process is as follows: the sintering temperature is 850-950 ℃, the sintering pressure is 40-80 MPa, and the sintering time is 10-60 min. According to the Mo-P binary phase diagram, the decomposition of MoP can be caused when the temperature is higher than 950 ℃. Theoretically, the higher the sintering temperature and the higher the sintering pressure, the higher the densification of the sintered product. The sintering mold is generally made of graphite, and pressure of more than 80MPa is difficult to apply. Under the pressure sintering process, high-density Mo can be stably obtained_1-xA_xP_1-yB_yThe density of the polycrystalline block reaches more than 80 percent and the conductivity is higher than 1 x 10⁶S/m (as described in Table 1).

The second purpose of the invention is to provide the molybdenum phosphide-based polycrystalline block prepared by the method.

It is a further object of the present invention to provide the use of said molybdenum phosphide-based polycrystalline mass as a self-supporting working electrode for electrocatalytic hydrogen and oxygen evolution.

Compared with the prior art, the invention has the following advantages and effects:

1. according to the preparation method of the molybdenum phosphide-based polycrystalline block, the MoP-based polycrystalline block material is prepared by combining solid-phase reaction with heating sintering for the first time, no by-product is generated, and the preparation method has the advantages of simple equipment and process, low production cost, suitability for large-scale production, environmental friendliness and the like; the material mainly adopts simple substance Mo powder, P powder, Nb powder, Se powder, Te powder and the like, and has rich sources and low cost of raw materials.

2. The conductivity of the molybdenum phosphide-based polycrystalline block provided by the invention reaches 10⁶The electrode has S/m magnitude, has the conductivity equivalent to that of working electrodes such as metallic nickel, carbon materials and the like, can be directly used for self-supporting working electrodes for electrocatalytic hydrogen and oxygen evolution, and does not need subsequent treatment.

3. The molybdenum phosphide-based polycrystalline block provided by the invention has excellent electrocatalytic properties: the current density is 10mAcm^-2The overpotential of the hydrogen evolution and oxygen evolution processes respectively reaches 205mV and 213mV, and the molybdenum phosphide-based polycrystalline block is integrally used as a working electrode and a catalyst, so that the stability is obviously improved, and the method can be widely applied to the field of electrocatalytic hydrogen evolution in water electrolysis and chlor-alkali industries.

Drawings

FIG. 1 shows the powder XRD patterns of MoP after solid phase reaction and after plasma activated sintering in example 1;

FIG. 2 is an SEM image of the powder after solid-phase reaction of MoP in example 1;

FIG. 3 is a SEM cross-section of a MoP plasma activated sintered mass of example 1;

FIG. 4 shows the hydrogen evolution overpotential diagram of the MoP polycrystalline bulk in the alkaline environment (1M KOH) of example 1; the hydrogen evolution overpotentials of the Pt/C electrode under the same conditions are listed as comparison;

FIG. 5 shows the oxygen evolution overpotential diagram of the MoP polycrystalline bulk of example 1 in alkaline environment (1M KOH); RuO₂The hydrogen evolution overpotentials of the/Ni electrode under the same conditions are listed as comparison;

FIG. 6 shows the MoP of examples 1-5_1-y(y is 0 to 0.07) sintering of polycrystalline blockPowder XRD spectrum;

FIG. 7 shows Mo in examples 6 to 8_1-xNb_xPowder XRD pattern of P (x is 0-0.06) sintered polycrystalline block;

FIG. 8 shows the MoP of examples 9-10_1-ySe_y(y is 0-0.02) powder XRD pattern of the sintered polycrystalline block;

FIG. 9 shows the MoP of examples 11-12_1-yTe_y(y is 0 to 0.02) powder XRD pattern of the sintered polycrystalline block.

FIG. 10 shows powder XRD patterns of MoP in Experimental example 2 after solid-phase reaction at different temperatures.

Detailed Description

Example 1

The embodiment provides a preparation method of a MoP polycrystalline block by combining solid-phase reaction and plasma activated sintering, which comprises the following steps:

1) elemental Mo powder and P powder with the purity of 99.9 percent are used as raw materials, and are weighed, ground and uniformly mixed according to the stoichiometric ratio of MoP to obtain a reactant;

2) tabletting the reactant obtained in the step 1), then vacuum-sealing the reactant in a quartz glass tube, and placing the quartz glass tube in a muffle furnace for reacting for 48 hours at 750 ℃ to obtain a reaction product;

3) grinding and refining the polycrystalline powder product obtained in the step 2), and then obtaining a compact polycrystalline product by adopting a plasma activation sintering method under the conditions of 950 ℃, 80MPa and 10min of heat preservation;

4) the surface of the plasma activated sintered MoP polycrystalline block body can be directly used for electrochemical hydrogen evolution and oxygen evolution experiments after being polished by 800-mesh sand paper.

FIG. 1 shows powder XRD patterns of MoP after solid-phase reaction and after plasma activated sintering; FIGS. 2 and 3 are SEM images of the cross sections of the MoP solid-phase reaction powder and the plasma activated sintering block respectively, and show the cross-sectional morphology of the prepared MoP polycrystalline block and the compact microstructure thereof; fig. 4 and 5 show the hydrogen evolution and oxygen evolution overpotentials of the MoP polycrystalline bulk under alkaline environment (1M KOH, PH 14), respectively. The hydrogen evolution overpotential of the Pt/C electrode under the same condition is 115mV, RuO₂The overpotential of hydrogen evolution of the/Ni electrode under the same condition is 319mV。

The MoP polycrystalline block body which is activated and sintered by plasma has compact structure and room-temperature conductivity as high as 6.74 multiplied by 10⁶S/m (shown in Table 1) is equivalent to the conductivity of a conventional working electrode such as metallic nickel and a carbon material. The MoP polycrystalline block has excellent electrochemical performance, and the hydrogen evolution overpotential and the oxygen evolution overpotential of the MoP polycrystalline block are 205mV and 213mV @10mAcm respectively^-2Can be directly used for electrochemical hydrogen and oxygen evolution without subsequent treatment.

Example 2

The present embodiment provides a MoP_1-yThe preparation method of the polycrystalline block by combining the solid-phase reaction with the plasma activated sintering comprises the following steps:

1) using simple substance Mo powder and P powder with the purity of 99.9% as raw materials according to the MoP_1-y(y is 0.01) weighing, grinding and uniformly mixing to obtain a reactant;

2) tabletting the reactant obtained in the step 1), then vacuum-sealing the reactant in a quartz glass tube, and placing the quartz glass tube in a muffle furnace for reacting for 48 hours at 750 ℃ to obtain a reaction product;

3) grinding and refining the polycrystalline powder product obtained in the step 2), and then obtaining a compact polycrystalline product by adopting a plasma activation sintering method under the conditions of 950 ℃, 80MPa and 10min of heat preservation;

4) plasma activated sintering (MoP)_0.99The surface of the polycrystalline block body can be directly used for electrochemical hydrogen and oxygen evolution experiments after being polished by sand paper.

Example 3

The present embodiment provides a MoP_1-yMethod for the production of polycrystalline masses by solid-phase reaction combined with plasma activated sintering, according to MoP_0.97(y is 0.03) stoichiometric ratio, and the procedure is as in example 2.

Example 4

The present embodiment provides a MoP_1-yMethod for the production of polycrystalline masses by solid-phase reaction combined with plasma activated sintering, according to MoP_0.95(y is 0.05) stoichiometric ratio, and the procedure is as in example 2.

Example 5

The present embodiment provides a MoP_1-ySolid phase reaction bonding of polycrystalline massesMethod for preparing by plasma activated sintering according to MoP_0.93(y is 0.07) stoichiometry, the procedure is as in example 2.

Example 6

This example provides a Mo_1-xNb_xThe preparation method of the P polycrystalline block by combining the solid-phase reaction with the plasma activated sintering comprises the following steps:

1) using simple substance Mo powder with the purity of 99.9%, Nb powder and P powder as raw materials according to the proportion of Mo_1-xNb_xP_1-yB_yWeighing and grinding the mixture according to the stoichiometric ratio (x is 0.02 and y is 0) and uniformly mixing to obtain a reactant;

2) tabletting the reactant obtained in the step 1), then vacuum-sealing the reactant in a quartz glass tube, and placing the quartz glass tube in a muffle furnace for reacting for 48 hours at 750 ℃ to obtain a reaction product;

3) grinding and refining the polycrystalline powder product obtained in the step 2), and then obtaining a compact polycrystalline product by adopting a plasma activation sintering method under the conditions of 950 ℃, 80MPa and 10min of heat preservation;

4) plasma activated sintering of Mo_1-xNb_xThe surface of the P polycrystalline block body can be directly used for electrochemical hydrogen and oxygen evolution experiments after being polished by abrasive paper.

Example 7

In this example, Mo is removed_1-xNb_xP_1-yB_yThe reaction mixture was weighed and mixed by grinding in a stoichiometric ratio (x is 0.03 and y is 0), and the rest of the procedure was the same as in example 6.

Example 8

In this example, Mo is removed_1-xNb_xP_1-yB_yThe reaction mixture was weighed and mixed by grinding in a stoichiometric ratio (x is 0.06 and y is 0), and the rest of the procedure was the same as in example 6.

Example 9

The present embodiment provides a MoP_1-ySe_yThe preparation method of the polycrystalline block by combining the solid-phase reaction with the plasma activated sintering comprises the following steps:

1) using simple substance Mo powder with the purity of 99.9%, P powder and Se powder as raw materials according to the proportion of Mo_1-xA_xP_1-ySe_y(x is 0, y is 0.005) in a stoichiometric ratio, and uniformly mixing the mixture by grinding to obtain a reactant;

2) tabletting the reactant obtained in the step 1), then vacuum-sealing the reactant in a quartz glass tube, and placing the quartz glass tube in a muffle furnace for reacting for 48 hours at 750 ℃ to obtain a reaction product;

3) grinding and refining the polycrystalline powder product obtained in the step 2), and then obtaining a compact polycrystalline product by adopting a plasma activation sintering method under the conditions of 950 ℃, 80MPa and 10min of heat preservation;

4) plasma activated sintering (MoP)_1-ySe_yThe surface of the polycrystalline block body can be directly used for electrochemical hydrogen and oxygen evolution experiments after being polished by sand paper.

Example 10

Examples are given by Mo_1-xA_xP_1-ySe_yThe reaction mixture was weighed and mixed by grinding in a stoichiometric ratio (x is 0 and y is 0.005), and the rest of the procedure was the same as in example 9.

Example 11

The present embodiment provides a MoP_1-yTe_yThe preparation method of the polycrystalline block by combining the solid-phase reaction with the plasma activated sintering comprises the following steps:

1) using simple substance Mo powder with purity of 99.9%, P powder and Te powder as raw material_1-xA_xP_1-yTe_y(x is 0, y is 0.005) in a stoichiometric ratio, and uniformly mixing the mixture by grinding to obtain a reactant;

2) tabletting the reactant obtained in the step 1), then vacuum-sealing the reactant in a quartz glass tube, and placing the quartz glass tube in a muffle furnace for reacting for 48 hours at 750 ℃ to obtain a reaction product;

3) grinding and refining the polycrystalline powder product obtained in the step 2), and then obtaining a compact polycrystalline product by adopting a plasma activation sintering method under the conditions of 950 ℃, 80MPa and 10min of heat preservation;

4) plasma activated sintering (MoP)_1-yTe_yThe surface of the polycrystalline block body can be directly used for electrochemical hydrogen and oxygen evolution experiments after being polished by sand paper.

Example 12

Examples are given by Mo_1-xA_xP_1-yTe_yThe reaction mixture was weighed and mixed by grinding in a stoichiometric ratio (x is 0 and y is 0.005), and the rest of the procedure was the same as in example 11.

Experimental example 1

The conductivity and the compactness of the molybdenum phosphide-based polycrystalline compacts prepared in examples 1 to 12 were evaluated as shown in Table 1.

TABLE 1

As can be seen from the variation trend of the doping amount influencing the density and the conductivity in Table 1, increasing the doping amount greatly reduces Mo_1-xA_xP_1-yDensity and conductivity of the By polycrystalline block; in this embodiment, Mo is added in the case where the doping amount x is 0-0.06 and y is 0-0.07_1-xA_xP_1-yB_yThe density of the polycrystalline block is higher than 80% and the conductivity is higher than 1 x 10⁶S/m, can be used as an electro-catalytic reaction catalyst and an in-situ working electrode without the assistance of an external working electrode. The x and y ranges chosen for this example are Mo_1-xA_xP_1-yB_yThe polycrystalline block body can be suitable for the doping amount range, and the problems that the density and the conductivity are too low and the capability of the polycrystalline block body serving as an in-situ working electrode is influenced due to too high doping amount are avoided.

FIG. 6 shows MoP of examples 1-5_1-y(y is 0 to 0.07) powder XRD pattern of the plasma activated sintered product. When P is deleted to y of 0.05 or more, MoP_1-yThe polycrystalline block has Mo impurity phase, the density and the conductivity of the polycrystalline block are obviously reduced (shown in table 1), but the conductivity of the polycrystalline block is kept at 3 x 10⁶And S/m is more than or equal to.

FIG. 7 shows Mo in examples 6 to 8_1-xNb_xAnd (3) powder XRD pattern of the P (x is 0-0.06) plasma activated sintering product. Nb is doped to exceedWhen y is 0.02, Mo_1-xNb_xNbP mixed phase appears in the P polycrystalline block, and the overall conductivity is kept unchanged (shown in table 1) and is as high as 6-7 multiplied by 10⁶S/m。

FIG. 8 shows MoP of examples 9-10_1-ySe_y(y is 0-0.02) powder XRD pattern of the plasma activated sintered product. After Se doping, MoP_1-ySe_yThe polycrystalline mass was a single phase with a significant decrease in density and conductivity (shown in Table 1), but still as high as 2.29X 10⁶And S/m is more than or equal to.

FIG. 9 shows MoP of examples 11-12_1-yTe_y(y is 0-0.02) powder XRD pattern of the plasma activated sintered product. After Te doping, MoP_1-yTe_yThe polycrystalline mass was a single phase with a significant reduction in density and conductivity (shown in Table 1), but still as high as 1.78X 10⁶And S/m is more than or equal to.

Experimental example 2 exploration of solid phase reaction temperature

The powder XRD pattern of MoP after solid phase reaction at different temperatures (650 deg.C, 700 deg.C, 750 deg.C) is shown in FIG. 10.

As can be seen from FIG. 10, when the solid-phase reaction time is 40-55 h, the solid-phase reaction temperature is lower than 700 ℃ and the reaction of Mo and P is incomplete, the product contains a large amount of MoP₂And a hetero phase of Mo simple substance. Therefore, in order to realize complete reaction of the simple substance element in the solid phase reaction and energy conservation, the invention uses Mo_1-xA_xP_1-yB_yThe solid phase reaction temperature of (2) is controlled within the range of 700-800 ℃.

The invention is not to be considered as limited to the particular embodiments shown, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.