阅读说明：本技术 双金属磷化物及其制备方法和应用 (Bimetallic phosphide and preparation method and application thereof ) 是由 邱永福 花开慧 陈孝东 陈易 范洪波 金具涛 于 2020-06-09 设计创作，主要内容包括：本发明涉及一种双金属磷化物及其制备方法和应用。该双金属磷化物的制备方法包括以下步骤：将铁氰化钾和钴盐进行共沉淀反应,制成铁钴普鲁士蓝；及在保护气氛下,将铁钴普鲁士蓝进行磷化处理,制成双金属磷化物。该双金属磷化物的制备方法简便,采用的原材料成本低、容易获得,可实现工业化规模生产,按照该方法制得的双金属磷化物具有丰富的多孔结构,呈规则的立方块形貌,粒径较为均匀,在催化剂领域或电极材料领域具有广阔的应用前景。(The invention relates to a bimetal phosphide and a preparation method and application thereof. The preparation method of the bimetal phosphide comprises the following steps: carrying out coprecipitation reaction on potassium ferricyanide and cobalt salt to prepare iron-cobalt Prussian blue; and under the protective atmosphere, carrying out phosphating treatment on the iron-cobalt Prussian blue to prepare the bimetal phosphide. The preparation method of the bimetal phosphide is simple and convenient, the adopted raw materials are low in cost and easy to obtain, industrial scale production can be realized, the bimetal phosphide prepared according to the method has rich porous structure, is in a regular cubic morphology, has uniform particle size, and has wide application prospect in the field of catalysts or electrode materials.)

1. The preparation method of the bimetal phosphide is characterized by comprising the following steps:

carrying out coprecipitation reaction on potassium ferricyanide and cobalt salt to prepare iron-cobalt Prussian blue; and

and under the protective atmosphere, carrying out phosphating treatment on the iron-cobalt Prussian blue to prepare the bimetal phosphide.

2. The method of claim 1, wherein the iron-cobalt Prussian blue has a chemical formula of Fe_0.667Co(CN)₄(H₂O)₄。

3. The method of claim 1, wherein the step of co-precipitating the potassium ferricyanide and the cobalt salt comprises: mixing and reacting a complexing agent, the potassium ferricyanide, the cobalt salt and water.

4. The method of claim 3, wherein the step of reacting the complexing agent, the potassium ferricyanide, the cobalt salt, and water comprises:

dissolving potassium ferricyanide in water to form a potassium ferricyanide solution;

dissolving cobalt salt in water to form a cobalt salt solution; and

and mixing the potassium ferricyanide solution, the cobalt salt solution and a complexing agent for reaction.

5. The method according to claim 3, wherein said complexing agent is at least one selected from the group consisting of sodium citrate and citric acid.

6. The method according to claim 1, wherein the cobalt salt is at least one selected from the group consisting of cobalt nitrate, cobalt sulfate, cobalt carbonate, cobalt chloride, cobalt bromide, cobalt iodide, and cobalt fluoride; and/or

The phosphorus source in the phosphating treatment is at least one selected from sodium hypophosphite, potassium hypophosphite and phosphine.

7. The method according to any one of claims 1 to 6, wherein the temperature of the phosphating treatment is 350 ℃ to 650 ℃.

8. The bimetal phosphide is characterized by being porous cubic iron-cobalt phosphide, the particle size of the bimetal phosphide is 300-350 nm, and the pore volume of the bimetal phosphide is 0.65cm³/g～0.75cm³The aperture of the bimetal phosphide is 45 nm-55 nm.

9. A catalyst for hydrogen production by water electrolysis, which is characterized by comprising the bimetallic phosphide prepared by the preparation method of the bimetallic phosphide of any one of claims 1-7 or the bimetallic phosphide of claim 8.

10. An electrode comprising an electrode active material, wherein the electrode active material comprises the bimetal phosphide prepared by the preparation method of the bimetal phosphide of any one of claims 1 to 7 or the bimetal phosphide of claim 8.

Technical Field

The invention relates to the technical field of metal phosphide, in particular to a bimetal phosphide and a preparation method and application thereof.

Background

With the continuous consumption of fossil fuels, various new energy production plans are receiving wide attention in order to meet the huge energy demand of the current. Hydrogen energy is expected to become the most effective substitute of fossil fuel as a clean energy with little pollution.

The hydrogen energy is mainly produced by electrochemically decomposing water to produce Hydrogen (HER), wherein direct current is introduced into an electrolytic cell filled with electrolyte, so that water molecules are electrochemically reacted on electrodes to be decomposed into hydrogen and oxygen. The method has the advantages of high efficiency, environmental friendliness, high gas production purity, strong energy fluctuation adaptability and the like. In order to further reduce the overpotential of the decomposed water and reduce the energy consumed by the reaction, catalysts are generally added, and noble metals such as Pt and Pd and oxides thereof have excellent catalytic activity for electrocatalytic decomposition of water, but the scarcity and high cost of the noble metal-based catalysts make them not widely used in industrial production.

Disclosure of Invention

Therefore, a need exists for a low-cost bimetallic phosphide capable of being applied to preparing a catalyst for hydrogen production by water electrolysis and a preparation method thereof.

A method for preparing a bimetallic phosphide comprises the following steps:

carrying out coprecipitation reaction on potassium ferricyanide and cobalt salt to prepare iron-cobalt Prussian blue; and

and under the protective atmosphere, carrying out phosphating treatment on the iron-cobalt Prussian blue to prepare the bimetal phosphide.

The preparation method of the bimetal phosphide is simple and convenient, the adopted raw materials are low in cost and easy to obtain, industrial scale production can be realized, the bimetal phosphide prepared by the method has rich porous structure, is in a regular cubic morphology, has uniform particle size, and has wide application prospect in the field of catalysts or electrode materials.

In addition, the preparation method of the bimetal phosphide takes the Prussian blue analogue as the bimetal precursor, and the unique bimetal phosphide prepared by phosphating can play a role in the synergy of two different metal ions, change the electronic structure of the catalyst and provide more surface reaction active sites, thereby improving the catalytic efficiency and stability of the catalyst. Therefore, compared with single metal phosphide, the double metal phosphide has better conductivity, is more favorable for electron transmission, and can further reduce the interface resistance of charge transfer and the surface reaction kinetic energy barrier, and further improve the electrocatalytic activity.

In one embodiment, the iron-cobalt Prussian blue has a chemical formula of Fe_0.667Co(CN)₄(H₂O)₄。

In one embodiment, the step of performing a coprecipitation reaction of potassium ferricyanide and a cobalt salt includes: mixing and reacting a complexing agent, the potassium ferricyanide, the cobalt salt and water.

In one embodiment, the step of mixing and reacting the complexing agent, the potassium ferricyanide, the cobalt salt and water comprises:

dissolving potassium ferricyanide in water to form a potassium ferricyanide solution;

dissolving cobalt salt in water to form a cobalt salt solution; and

and mixing the potassium ferricyanide solution, the cobalt salt solution and a complexing agent for reaction.

In one embodiment, the complexing agent is selected from at least one of sodium citrate and citric acid.

In one embodiment, the cobalt salt is selected from at least one of cobalt nitrate, cobalt sulfate, cobalt carbonate, cobalt chloride, cobalt bromide, cobalt iodide, and cobalt fluoride.

In one embodiment, the phosphorus source in the phosphating treatment is selected from at least one of sodium hypophosphite, potassium hypophosphite and phosphine.

In one embodiment, the temperature of the phosphating treatment is 350-650 ℃.

The bimetal phosphide is porous cubic iron-cobalt phosphide, the particle size of the bimetal phosphide is 300-350 nm, and the pore volume of the bimetal phosphide is 0.65cm³/g～0.75cm³The aperture of the bimetal phosphide is 45 nm-55 nm.

The bimetal phosphide prepared by the preparation method of the bimetal phosphide or the application of the bimetal phosphide in preparing a catalyst or an electrode material.

The catalyst for producing hydrogen by electrolyzing water comprises the bimetallic phosphide prepared by the preparation method of the bimetallic phosphide or the bimetallic phosphide.

An electrode comprises an electrode active material, wherein the electrode active material comprises the bimetal phosphide prepared by the preparation method of the bimetal phosphide or the bimetal phosphide.

Drawings

FIG. 1 is a scanning electron micrograph of iron cobalt Prussian blue of example 1;

FIG. 2 is a transmission electron micrograph of iron cobalt Prussian blue of example 1;

FIG. 3 is a scanning electron micrograph of the bimetallic phosphide of example 1;

FIG. 4 is a transmission electron micrograph of the bimetallic phosphide of example 1;

FIG. 5 is a scanning electron micrograph of a metal phosphide of comparative example 1.

Detailed Description

In order that the invention may be more fully understood, reference will now be made to the following description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

An embodiment of the invention provides a preparation method of a bimetal phosphide, which is simple and convenient, adopts low-cost raw materials, is easy to obtain, and can realize industrial mass production. The bimetal phosphide prepared by the method has rich porous structure, is in a regular cubic shape and has uniform particle size. Compared with the metal phosphide prepared by the traditional method, the precursor of the method can be prepared at normal temperature, and the bimetal phosphide prepared by the method has more regular appearance and more prominent three-dimensional porous structure, and has wide application prospect in the field of catalysts or electrode materials.

Specifically, the preparation method of the bimetal phosphide comprises the following steps of S110-S120:

step S110: and (3) carrying out coprecipitation reaction on potassium ferricyanide and cobalt salt to prepare the iron-cobalt Prussian blue.

Specifically, potassium ferricyanide and cobalt salt are dissolved in water for coprecipitation reaction to prepare iron-cobalt Prussian blue.

Prussian Blue (PB), ferricyanide (ferricyanide), Berlin Blue (Berlin Bue), Gong Blue, iron Blue, Miloli Blue, Chinese Blue (Chinese Blue), Hualan and Ore Blue, and the chemical formula is Fe₄[Fe(CN)₆]₃The metal organic framework compound (MOF) is simple in structure, simple and convenient to prepare, low in price and long in history. A large amount of Prussian blue analogues can be prepared by selecting proper transition metal ions (Co, Fe, Ni, Mn, Pt, Cr and the like) to replace ferrous ions and ferric ions in Prussian blue.

The Prussian blue analogue has the advantages of adjustable morphology, good molecular tuning capability, high porosity, high specific surface area and the like. The Prussian blue analogue is used as a bimetallic precursor, and a unique bimetallic phosphide prepared by phosphating can play a role in synergy of two different metal ions, change the electronic structure of the catalyst and provide more surface reaction active sites, so that the catalytic efficiency and stability of the catalyst are improved. Therefore, compared with single metal phosphide, the double metal phosphide has better conductivity, is more favorable for electron transmission, and can further reduce the interface resistance of charge transfer and the surface reaction kinetic energy barrier, and further improve the electrocatalytic activity.

Specifically, the cobalt salt is a divalent cobalt salt soluble in water. Further, the cobalt salt is at least one selected from the group consisting of cobalt nitrate, cobalt sulfate, cobalt carbonate, cobalt chloride, cobalt bromide, cobalt iodide, and cobalt fluoride. The cobalt nitrate may be anhydrous cobalt nitrate or hexahydrate. Further, the cobalt salt is selected from one of cobalt nitrate, cobalt sulfate, cobalt carbonate, cobalt chloride, cobalt bromide, cobalt iodide and cobalt fluoride.

More specifically, the complexing agent, potassium ferricyanide and cobalt salt are mixed and reacted to prepare the iron-cobalt Prussian blue. The complexing agent is complexed with metal ions to slowly release the metal ions, so that the crystal structure defect of the prepared iron-cobalt Prussian blue caused by extremely high reaction speed is avoided.

In one embodiment, the complexing agent is selected from at least one of sodium citrate and citric acid. Preferably, the complexing agent is selected from one of citric acid and sodium citrate.

In one embodiment, the step of mixing and reacting the complexing agent, the potassium ferricyanide and the cobalt salt comprises: dissolving potassium ferricyanide in water to form a potassium ferricyanide solution; dissolving cobalt salt in water to form a cobalt salt solution; and mixing potassium ferricyanide solution, cobalt salt solution and complexing agent for reaction. The method is characterized in that potassium ferricyanide and cobalt salt are respectively dissolved in water and then mixed with a complexing agent for reaction, so that the uniform reaction of the potassium ferricyanide and the cobalt salt is facilitated, and the formed iron-cobalt Prussian blue is uniform in shape. Of course, in other embodiments, the potassium ferricyanide and the cobalt salt do not need to be separately prepared into solution and then mixed for reaction, and the potassium ferricyanide, the cobalt salt and the complexing agent can be dissolved in water together.

Specifically, the temperature of the mixing reaction of the complexing agent, potassium ferricyanide and cobalt salt is 15-50 ℃. In one embodiment, the temperature for mixing and reacting the complexing agent, the potassium ferricyanide and the cobalt salt is 15-30 ℃. The reaction is carried out at a lower temperature, which is beneficial to improving the shape uniformity of the formed iron-cobalt Prussian blue.

Specifically, the mixing mode of the mixing reaction of the complexing agent, the potassium ferricyanide and the cobalt salt is stirring and mixing. Of course, in other embodiments, the mixing method for mixing and reacting the complexing agent, the potassium ferricyanide and the cobalt salt is not limited to stirring and mixing, and may be other mixing methods commonly used in the art.

Specifically, the reaction time of the mixed reaction of the complexing agent, the potassium ferricyanide and the cobalt salt is 5-30 h. In one embodiment, the reaction time of the mixing reaction of the complexing agent, the potassium ferricyanide and the cobalt salt is 24-30 h.

In one embodiment, the cobalt salt is cobalt nitrate hexahydrate, and the mass ratio of potassium ferricyanide to the cobalt salt is 1: 0.8-1.2. Preferably, the cobalt salt is cobalt nitrate hexahydrate, and the mass ratio of potassium ferricyanide to cobalt salt is 1: 1.

in one embodiment, the chemical formula of the iron-cobalt Prussian blue prepared by coprecipitation reaction of potassium ferricyanide and cobalt salt is Fe_0.667Co(CN)₄(H₂O)₄。

Of course, after the coprecipitation reaction of potassium ferricyanide and cobalt salt is finished, the method also comprises the step of washing and drying the product of the coprecipitation reaction.

Step S120: under the protective atmosphere, carrying out phosphating treatment on iron-cobalt Prussian blue to prepare the bimetal phosphide.

Specifically, the phosphorus source in the phosphating treatment is at least one selected from sodium hypophosphite, potassium hypophosphite and phosphine. In one embodiment, the phosphorus source in the phosphating treatment is selected from one of sodium phosphate, potassium hypophosphite and phosphine. Preferably, the phosphorus source in the phosphating treatment is selected from one of sodium phosphate and potassium hypophosphite.

Specifically, the temperature of the phosphating treatment is 350-650 ℃. In one embodiment, the temperature of the phosphating treatment is 580 ℃ to 650 ℃.

Specifically, the gas of the protective atmosphere is an inert gas. In one embodiment, the gas of the protective atmosphere is nitrogen or argon.

In one embodiment, the mass ratio of the iron-cobalt prussian blue to the phosphorus source is 1: 10. further, the mass ratio of the iron-cobalt Prussian blue to the phosphorus source is 1:4 to 10.

In one embodiment, the phosphorus source is sodium hypophosphite, and the mass ratio of iron-cobalt-prussian blue to the phosphorus source is 1: 2 to 10. Preferably, the phosphorus source is sodium hypophosphite, and the mass ratio of the iron-cobalt-Prussian blue to the phosphorus source is 1:4 to 10.

In one embodiment, iron-cobalt Prussian blue and sodium hypophosphite are respectively put into two porcelain boats according to the mass ratio of 1:5, wherein the porcelain boat filled with the sodium hypophosphite is put above the airflow, then argon is introduced, and the reaction is carried out for two hours at 600 ℃ to prepare the bimetallic phosphide.

The invention also provides a bimetal phosphide prepared by the preparation method of the bimetal phosphide. Specifically, the bimetal phosphide is porous cubic iron-cobalt phosphide, the particle size of the bimetal phosphide is 300-350 nm, and the pore volume of the bimetal phosphide is 0.65cm³/g～0.75cm³The pore diameter of the bimetal phosphide is 45nm to 55 nm.

The bimetal phosphide has a rich porous structure, is in a regular cubic shape, has uniform particle size, and can be applied to the field of catalysts or electrode materials.

The invention also provides an application of the bimetallic phosphide in hydrogen production by water electrolysis.

The invention also provides an application of the bimetallic phosphide in preparation of a catalyst or an electrode material.

Specifically, the bimetal phosphide is applied to preparation of a catalyst for hydrogen production by water electrolysis or preparation of an electrode material of a lithium battery.

The invention also provides a catalyst for producing hydrogen by electrolyzing water, which comprises the bimetallic phosphide.

An embodiment of the present invention also provides an electrode comprising an electrode active material comprising the above-described bimetallic phosphide.

Specifically, the electrode further includes at least one of a conductive agent, a dispersant, and a binder.

In one embodiment, the binder is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, and sodium carboxymethylcellulose. Of course, it is to be understood that, in the embodiments, the adhesive is not limited to the above, but may be other adhesives commonly used in the art.

In one embodiment, the dispersant is selected from at least one of N-methyl pyrrolidone, N-methyl-2-pyrrolidone, and deionized water. Of course, it is understood that in the examples, the dispersant is not limited to the above, but may be other dispersants commonly used in the art.

In one embodiment, the conductive agent is selected from at least one of carbon black, activated carbon, and mesoporous carbon. Of course, it is to be understood that, in the embodiments, the conductive agent is not limited to the above, but may be other conductive agents commonly used in the art.

The electrode comprises the bimetal phosphide, and the bimetal phosphide has a rich porous structure, is in a regular cubic shape and has uniform particle size, so that the specific capacitance of the electrode is large, and the stability is good.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The following detailed description is given with reference to specific examples. The examples, which are not specifically illustrated, employ drugs and equipment, all of which are conventional in the art. The experimental procedures, in which specific conditions are not indicated in the examples, were carried out according to conventional conditions, such as those described in the literature, in books, or as recommended by the manufacturer.

Example 1

(1) The method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

dissolving 0.65g of potassium ferricyanide in 100mL of water, pouring the solution into 100mL of water containing 0.65g of cobalt nitrate hexahydrate and 1.3g of sodium citrate under stirring, and stirring the solution at room temperature for reaction for 24 hours to obtain the compound of the formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (3) photographing the iron-cobalt Prussian blue obtained in the step (1) by a scanning electron microscope and a transmission electron microscope, wherein the results are shown in a figure 1 and a figure 2. Fig. 1 is a scanning electron microscope image of the iron-cobalt prussian blue prepared in the step (1), and fig. 2 is a transmission electron microscope image of the iron-cobalt prussian blue prepared in the step (1).

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 100mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing argon, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) photographing the bimetal phosphide prepared in the step (3) by a scanning electron microscope and a transmission electron microscope, wherein the results are shown in fig. 3 and 4. Fig. 3 is a scanning electron microscope image of the bimetal phosphide prepared in the step (3), and fig. 4 is a transmission electron microscope image of the bimetal phosphide prepared in the step (3).

As can be seen from FIGS. 1 and 2, the iron-cobalt Prussian blue prepared in step (1) has a uniform particle size of about 200nm and a smooth surface.

As can be seen from fig. 3 and 4, the bimetallic phosphide prepared in step (3) maintained the cubic structure of prussian blue and produced an abundant pore structure during the phosphating process.

Example 2

Compared with example 1, example 2 has twice the amount of the reactant for preparing iron-cobalt prussian blue compared with example 1, and the specific steps are as follows:

(1) the method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

dissolving 1.3g of potassium ferricyanide in 100mL of water, pouring the solution into 100mL of water containing 1.3g of cobalt nitrate hexahydrate and 2.6g of sodium citrate under stirring, and stirring the solution at room temperature for reaction for 24 hours to obtain the compound of the formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (2) taking pictures of the iron-cobalt Prussian blue obtained in the step (1) through a scanning electron microscope and a transmission electron microscope.

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 100mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing argon, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) taking pictures of the bimetal phosphide prepared in the step (3) through a scanning electron microscope and a transmission electron microscope.

Comparing the iron-cobalt prussian blue and the bimetallic phosphide prepared in example 2 with the iron-cobalt prussian blue and the bimetallic phosphide prepared in example 1, it was found that the iron-cobalt prussian blue prepared in example 2 is not significantly different from the iron-cobalt prussian blue prepared in example 1, and the bimetallic phosphide prepared in example 2 is not significantly different from the bimetallic phosphide prepared in example 1. It can be seen that the raw materials for preparing the bimetallic phosphide according to the above method can be multiplied, and the preparation method is stable and can be used for large-scale production.

Example 3

Compared with the example 1, the cobalt salt of the example 3 is cobalt nitrate, and the specific details are as follows:

(1) the method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

dissolving 0.65g of potassium ferricyanide in 100mL of water, pouring the solution into 100mL of water containing 0.41g of cobalt nitrate and 1.3g of sodium citrate under stirring, and stirring the solution at room temperature for 24 hours to obtain the compound of the formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (2) taking pictures of the iron-cobalt Prussian blue obtained in the step (1) through a scanning electron microscope and a transmission electron microscope.

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 100mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing argon, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) taking pictures of the bimetal phosphide prepared in the step (3) through a scanning electron microscope and a transmission electron microscope.

Comparing the iron-cobalt prussian blue and the bimetallic phosphide prepared in example 3 with the iron-cobalt prussian blue and the bimetallic phosphide prepared in example 1, it was found that the iron-cobalt prussian blue prepared in example 3 was not significantly different from the iron-cobalt prussian blue prepared in example 1, and the bimetallic phosphide prepared in example 3 was not significantly different from the bimetallic phosphide prepared in example 1.

Example 4

The amount of sodium hypophosphite was increased to 200mg compared to example 1, as follows:

(1) the method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

dissolving 0.65g of potassium ferricyanide in 100mL of water, pouring the solution into 100mL of water containing 0.65g of cobalt nitrate hexahydrate and 1.3g of sodium citrate under stirring, and stirring the solution at room temperature for reaction for 24 hours to obtain the compound of the formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (2) taking pictures of the iron-cobalt Prussian blue obtained in the step (1) through a scanning electron microscope and a transmission electron microscope.

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 200mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing argon, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) taking pictures of the bimetal phosphide prepared in the step (3) through a scanning electron microscope and a transmission electron microscope.

Comparing the bimetallic phosphide prepared in example 4 with the bimetallic phosphide prepared in example 1, it was found that the bimetallic phosphide prepared in example 4 was not significantly different from the bimetallic phosphide prepared in example 1.

Example 5

Compared with the embodiment 1, the protection atmosphere is changed from argon to nitrogen, and the specific steps are as follows:

(1) the method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

0.65g of potassium ferricyanide was dissolved in 100mL of water, and then poured into 100mL of a solution containing 0.65g of cobalt nitrate hexahydrate and 1.3g of sodium citrate with stirring, followed by reaction with stirring at room temperature 24h, obtaining a compound of formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (2) taking pictures of the iron-cobalt Prussian blue obtained in the step (1) through a scanning electron microscope and a transmission electron microscope.

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 100mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing nitrogen, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) taking pictures of the bimetal phosphide prepared in the step (3) through a scanning electron microscope and a transmission electron microscope.

Comparing the bimetallic phosphide prepared in example 5 with the bimetallic phosphide prepared in example 1, it was found that the bimetallic phosphide prepared in example 5 was not significantly different from the bimetallic phosphide prepared in example 1.

Example 6

Compared with the example 1, the cobalt salt is changed from cobalt nitrate hexahydrate to cobalt sulfate, which comprises the following specific steps:

(1) the method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

dissolving 0.65g of potassium ferricyanide in 100mL of water, pouring the solution into 100mL of water containing 0.63g of cobalt sulfate and 1.3g of sodium citrate under stirring, and stirring the solution at room temperature for 24 hours to obtain the compound of the formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (2) taking pictures of the iron-cobalt Prussian blue obtained in the step (1) through a scanning electron microscope and a transmission electron microscope.

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 100mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing nitrogen, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) taking pictures of the bimetal phosphide prepared in the step (3) through a scanning electron microscope and a transmission electron microscope.

Comparing the bimetallic phosphide obtained in example 6 with the bimetallic phosphide obtained in example 1, it was found that the bimetallic phosphide obtained in example 6 was not significantly different from the bimetallic phosphide obtained in example 1.

Example 7

Compared with the example 1, the cobalt salt is changed from cobalt nitrate hexahydrate to cobalt carbonate, which comprises the following specific steps:

(1) the method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

dissolving 0.65g of potassium ferricyanide in 100mL of water, pouring the solution into 100mL of water containing 0.27g of cobalt carbonate and 1.3g of sodium citrate under stirring, and stirring the solution at room temperature for 24 hours to obtain the compound of the formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (2) taking pictures of the iron-cobalt Prussian blue obtained in the step (1) through a scanning electron microscope and a transmission electron microscope.

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 100mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing nitrogen, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) taking pictures of the bimetal phosphide prepared in the step (3) through a scanning electron microscope and a transmission electron microscope.

Comparing the bimetallic phosphide prepared in example 7 with the bimetallic phosphide prepared in example 1, it was found that the bimetallic phosphide prepared in example 7 was not significantly different from the bimetallic phosphide prepared in example 1.

Example 8

Compared with the example 1, the cobalt salt is changed from cobalt nitrate hexahydrate to cobalt chloride, which comprises the following specific steps:

(1) the method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

dissolving 0.65g of potassium ferricyanide in 100mL of water, pouring the solution into 100mL of water containing 0.29g of cobalt chloride and 1.3g of sodium citrate under stirring, and stirring the solution at room temperature for 24 hours to obtain the compound of the formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (2) taking pictures of the iron-cobalt Prussian blue obtained in the step (1) through a scanning electron microscope and a transmission electron microscope.

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 100mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing nitrogen, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) taking pictures of the bimetal phosphide prepared in the step (3) through a scanning electron microscope and a transmission electron microscope.

Comparing the bimetallic phosphide obtained in example 8 with the bimetallic phosphide obtained in example 1, it was found that the bimetallic phosphide obtained in example 8 was not significantly different from the bimetallic phosphide obtained in example 1.

Example 9

Compared with the example 1, the cobalt salt is changed from cobalt nitrate hexahydrate to cobalt bromide, and the specific steps are as follows:

(1) the method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

dissolving 0.65g of potassium ferricyanide in 100mL of water, pouring the solution into 100mL of water containing 0.53g of cobalt bromide and 1.3g of sodium citrate under stirring, and stirring the solution at room temperature for 24 hours to obtain the compound of the formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (2) taking pictures of the iron-cobalt Prussian blue obtained in the step (1) through a scanning electron microscope and a transmission electron microscope.

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 100mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing nitrogen, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) taking pictures of the bimetal phosphide prepared in the step (3) through a scanning electron microscope and a transmission electron microscope.

Comparing the bimetallic phosphide prepared in example 9 with the bimetallic phosphide prepared in example 1, it was found that the bimetallic phosphide prepared in example 9 was not significantly different from the bimetallic phosphide prepared in example 1.

Example 10

Compared with the example 1, the cobalt salt is changed from cobalt nitrate hexahydrate to cobalt iodide as follows:

(1) the method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

dissolving 0.65g of potassium ferricyanide in 100mL of water, pouring the solution into 100mL of water containing 0.70g of cobalt iodide and 1.3g of sodium citrate under stirring, and stirring the solution at room temperature for 24 hours to obtain the compound of the formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (2) taking pictures of the iron-cobalt Prussian blue obtained in the step (1) through a scanning electron microscope and a transmission electron microscope.

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 100mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing nitrogen, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) taking pictures of the bimetal phosphide prepared in the step (3) through a scanning electron microscope and a transmission electron microscope.

Comparing the bimetallic phosphide prepared in example 10 with the bimetallic phosphide prepared in example 1, it was found that the bimetallic phosphide prepared in example 10 was not significantly different from the bimetallic phosphide prepared in example 1.

Example 11

Compared with the example 1, the cobalt salt is changed from cobalt nitrate hexahydrate to cobalt fluoride, and the specific steps are as follows:

(1) the method for preparing the cubic iron-cobalt Prussian blue comprises the following specific operation steps:

dissolving 0.65g of potassium ferricyanide in 100mL of water, pouring the solution into 100mL of water containing 0.22g of cobalt fluoride and 1.3g of sodium citrate under stirring, and stirring the solution at room temperature for 24 hours to obtain the compound of the formula Fe_0.667Co(CN)₄(H₂O)₄Iron cobalt prussian blue.

(2) And (2) taking pictures of the iron-cobalt Prussian blue obtained in the step (1) through a scanning electron microscope and a transmission electron microscope.

(3) The preparation method of the bimetal phosphide comprises the following specific steps: and (2) respectively putting 20mg of Prussian blue prepared in the step (1) and 100mg of sodium hypophosphite into two ceramic boats, wherein the ceramic boats filled with the sodium hypophosphite are put above airflow, then introducing nitrogen, and reacting for two hours at 600 ℃ to obtain the bimetallic phosphide.

(4) And (4) taking pictures of the bimetal phosphide prepared in the step (3) through a scanning electron microscope and a transmission electron microscope.

Comparing the bimetallic phosphide prepared in example 11 with the bimetallic phosphide prepared in example 1, it was found that the bimetallic phosphide prepared in example 11 was not significantly different from the bimetallic phosphide prepared in example 1.

Comparative example 1

(1) Synthesizing a cobaltosic oxide precursor: 0.5M cobalt nitrate hexahydrate is dissolved in 100mL of deionized water, then the mixture is stirred at 80 ℃ for 15 minutes, then 5mL of acetylacetone and 4.75mL of 85% hydrazine hydrate are added into the solution, then the mixture is stirred and reacted for 10 minutes, and then the obtained precipitate is filtered, washed by deionized water and finally dried at 60 ℃ for 24 hours to obtain a cobaltosic oxide precursor.

(2) Synthesizing metal phosphide: and heating the cobaltosic oxide precursor and sodium hypophosphite for 2 hours at 350 ℃ to obtain the metal phosphide. Wherein the mass ratio of the cobaltosic oxide precursor to the sodium hypophosphite is 1: 4.

(3) And (3) taking pictures of the metal phosphide prepared in the step (2) by a scanning electron microscope and a transmission electron microscope, wherein the pictures of the scanning electron microscope are shown in figure 5. Comparing the metal phosphide prepared in the comparative example 1 with the bimetal phosphide prepared in the example 1, the metal phosphide prepared in the comparative example 1 is obviously different from the bimetal phosphide prepared in the example 1, and the metal phosphide prepared in the example 1 has more regular morphology and more uniform particle size.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.