CN101973537A - Method for preparing transition metal phosphide - Google Patents

Abstract

The invention discloses a preparation method of a transition metal phosphide. Add ethylene glycol and water according to the volume ratio, mix and stir evenly, then add nickel salt, stir until the solution becomes transparent, add yellow phosphorus therein, and then make the solution under airtight condition Heating from room temperature to carry out the reaction at 140-180°C for 12 hours; after the completion of the reaction, cool to room temperature with the furnace, and then filter to obtain the crude product; then wash with benzene, ethanol and distilled water in sequence; put the washed product into vacuum drying The product was obtained by vacuum drying at 50°C in an oven. The present invention adopts the method of carrying out solid-liquid reaction in solvothermal system, thereby can realize the preparation of metal phosphide catalytic material at relatively low temperature, using conventional equipment, and water and ethylene glycol are used as reaction solvent, has reduced production cost, simplify the production process, avoid the pollution of toxic by-products, and increase the yield. It also avoids the use of toxic, difficult-to-synthesize metal-organic compounds and expensive raw materials.

Description

A kind of preparation method of transition metal phosphide

technical field

The invention belongs to the field of solvothermal synthesis preparation methods, in particular to a preparation technology involving transition metal phosphides with two compositions.

Background technique

Transition metal phosphides are another new type of catalytic material after transition metal carbides and nitrides. Due to their similar physical properties to carbides and nitrides and excellent hydrodesulfurization and denitrification activities and selectivity, It has thus become a hotspot in the field of new catalytic materials research and has been successfully applied in chemical fields such as petroleum processing. Nickel phosphide is a very good anti-oxidation, anti-corrosion and wear-resistant material. It is a new type of catalytic material, light-emitting device and electronic component material with high activity, high stability and anti-sulfur poisoning performance, so its application prospect is very broad.

At present, the preparation methods of nickel phosphide mainly include: direct compounding of simple substances under high temperature protective gas; solid-state displacement reaction of nickel chloride and phosphine; reaction of nickel chloride and phosphine; decomposition of organometallic compounds; reduction of nickel phosphate ; Nickel chloride and sodium hypophosphite reaction preparation. Among all these preparation methods, some require high temperature, some require very expensive raw materials, or the by-products generated will cause phosphide pollution. The method of temperature-programmed reduction to prepare phosphide is to use metal salts (such as nickel nitrate) and ammonium phosphate oxides as precursors, and gradually increase the temperature and reduce them in _H2 atmosphere. However, in addition to the high preparation temperature (higher than 550°C) and the slow heating rate that are difficult to achieve in large-scale production, in order to avoid intense oxidation reactions, the prepared fresh phosphide needs to be surface passivated before it can be produced. exposed to air. Park et al. reported that a transition metal phosphine was prepared by using n-octyl phosphine (TOP) or n-octyl phosphine oxide as a solvent to react with a transition metal carbonyl compound in liquid phase. However, there are still some problems in this method, such as the high price of TOP, and it can only be used to prepare non-supported transition metal phosphides. Transition metal phosphides can also be prepared by solvothermal method, but the phosphides obtained by solvothermal method reported so far are mostly random particles.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the existing production process, such as expensive raw materials and equipment costs, or irregular product particles, etc., to provide a preparation method for transition metal phosphides, which not only has a simple production process, but also has a high yield and no Toxic by-product contamination.

The purpose of the present invention is solved by the following technical solutions:

The preparation method of this kind of transition metal phosphide of the present invention comprises the following steps:

1) Add ethylene glycol and water with a volume ratio of 1: (1 to 4) into the autoclave, mix and stir the solution evenly, add 0.01 to 0.03 g of nickel salt per milliliter of the solution, and stir until the solid is completely dissolved and formed clear solution;

2) Transfer the transparent solution into the polytetrafluoroethylene lining, add 0.005 ~ 0.02g of yellow phosphorus to each milliliter of the transparent solution, then seal the polytetrafluoroethylene lining into a stainless steel mold, and make it under airtight condition by room temperature Start heating and heat the reaction at 140-180°C for 12h;

3) After the reaction is completed, cool to room temperature with the furnace, and then filter with rapid quantitative filter paper to obtain the crude product;

4) washing the crude product with benzene, ethanol and distilled water successively;

5) Put the washed product into a vacuum drying oven, and dry it in vacuum at 50° C. for 4 hours to obtain the transition metal phosphide.

Further, the nickel salt in the above step 1) is nickel sulfate, nickel chloride or nickel nitrate.

The present invention has the following beneficial effects:

The present invention adopts the method of carrying out solid-liquid reaction in solvothermal system, thereby can realize the preparation of metal phosphide catalytic material at relatively low temperature, using conventional equipment, and water and ethylene glycol are used as reaction solvent, has reduced production cost, simplify the production process, avoid the pollution of toxic by-products, and increase the yield. It also avoids the use of toxic, difficult-to-synthesize metal-organic compounds and expensive raw materials.

Description of drawings

Fig. 1 is the pattern obtained by XRD analysis of the product _Ni2P prepared by the present invention;

Fig. 2 is the pattern obtained by XRD analysis of the product Ni ₁₂ P ₅ prepared by the present invention;

Fig. 3 (A) is the photo of Ni ₂ P microspheres of the product of the present invention; (B) is the photo of Ni ₂ P dendrites of the product of the present invention; (C) is the photo of Ni ₁₂ P ₅ microspheres of the product of the present invention;

Fig. 4 is the growth process of product Ni of the present invention _P dendrite;

Fig. 5 is the phase diagram of Ni ₂ P powder prepared in embodiment 4;

Fig. 6 is the phase diagram of Ni ₂ P powder prepared in embodiment 5;

Fig. 7 is the phase diagram of Ni ₂ P powder prepared in embodiment 6;

FIG. 8 is a phase diagram of Ni ₂ P powder prepared in Example 7. FIG.

Detailed ways

The present invention is described in further detail below in conjunction with accompanying drawing:

Example 1

The preparation method of the transition metal phosphide of the present embodiment is carried out according to the following steps:

1) Add ethylene glycol and water with a volume ratio of 1:1 into the autoclave, mix and stir the solution evenly, add 0.01g of nickel salt per milliliter of the solution, and stir until the solid is completely dissolved to form a transparent solution; the nickel salt Select nickel sulfate;

2) transfer the transparent solution into the polytetrafluoroethylene lining of 50mL, the filling degree of this polytetrafluoroethylene lining is 80%, add the yellow phosphorus of 0.005g in every milliliter of transparent solution, then put the polytetrafluoroethylene The lining is sealed into a stainless steel mold, heated from room temperature under airtight conditions and reacted at 140°C for 12 hours;

3) After the reaction is completed, cool to room temperature with the furnace, and then filter with rapid quantitative filter paper to obtain the crude product;

4) washing the crude product twice with benzene, ethanol and distilled water in sequence;

5) Put the washed product into a vacuum drying oven, and dry it in vacuum at 50° C. for 4 hours to obtain the transition metal phosphide.

Example 2

The preparation method of the transition metal phosphide of the present embodiment is carried out according to the following steps:

1) Add ethylene glycol and water with a volume ratio of 1:3 into the autoclave, mix and stir the solution evenly, add 0.03g of nickel salt per milliliter of the solution, and stir until the solid is completely dissolved to form a transparent solution; the nickel salt Select nickel chloride;

2) transfer the transparent solution into the polytetrafluoroethylene liner of 50mL, the filling degree of this polytetrafluoroethylene liner is 80%, add the yellow phosphorus of 0.02g in every milliliter of transparent solution, then put the polytetrafluoroethylene The lining is sealed into a stainless steel mold, heated from room temperature under airtight conditions and reacted at 180°C for 12 hours;

3) After the reaction is completed, cool to room temperature with the furnace, and then filter with rapid quantitative filter paper to obtain the crude product;

4) The crude product is washed 3 times with benzene, ethanol and distilled water successively;

5) Put the washed product into a vacuum drying oven, and dry it in vacuum at 50° C. for 4 hours to obtain the transition metal phosphide.

Example 3

The preparation method of the transition metal phosphide of the present embodiment is carried out according to the following steps:

1) Add ethylene glycol and water with a volume ratio of 1:2 into the autoclave, mix and stir the solution evenly, add 0.02g of nickel salt per milliliter of the solution, and stir until the solid is completely dissolved to form a transparent solution; the nickel salt Select nickel nitrate;

2) transfer the transparent solution into the polytetrafluoroethylene lining of 50mL, the filling degree of this polytetrafluoroethylene lining is 80%, add the yellow phosphorus of 0.01g in every milliliter of transparent solution, then put the polytetrafluoroethylene The lining is sealed into a stainless steel mold, heated from room temperature under airtight conditions and reacted at 160°C for 12 hours;

3) After the reaction is completed, cool to room temperature with the furnace, and then filter with rapid quantitative filter paper to obtain the crude product;

4) The crude product is washed 3 times with benzene, ethanol and distilled water successively;

5) Put the washed product into a vacuum drying oven, and dry it in vacuum at 50° C. for 4 hours to obtain the transition metal phosphide.

Example 4:

The preparation method of the transition metal phosphide proposed in this embodiment is completed according to the following instructions:

First, mix and stir ethylene glycol and water according to the volume ratio of 1:4, take 40mL and put it into the reaction kettle, then add 0.525g of nickel sulfate (NiSO ₄ ·6H ₂ O), stir the solution until it becomes transparent, then transfer the solution into 50mL polytetrafluoroethylene lining; then add excess yellow phosphorus 0.31g to the transparent solution, seal the lining into a stainless steel mold, raise it from room temperature to 160°C, and keep it warm for 12h; then cool to room temperature with the furnace, The obtained powder is washed with ethanol, benzene and distilled water for 2-3 times respectively, placed in a vacuum drying oven, and vacuum-dried at 50° C. for 4 hours to obtain the product powder, which is the transition metal phosphide described in the present invention.

The phase of the Ni ₂ P powder prepared in this example is shown in Figure 5, and it can be seen from the figure that the obtained Ni ₂ P powder has a pure phase.

Example 5:

First, mix and stir ethylene glycol and water according to the volume ratio of 1:4, take 40mL and put it into the reaction kettle, then add 0.525g of nickel sulfate (NiSO ₄ ·6H ₂ O), stir the solution until it becomes transparent, then transfer the solution into 50mL polytetrafluoroethylene lining; then add excess yellow phosphorus 0.31g to the transparent solution, seal the lining into a stainless steel mold, raise it from room temperature to 180°C, and keep it warm for 12h; then cool to room temperature with the furnace, The obtained powder is washed with ethanol, benzene and distilled water for 2-3 times respectively, placed in a vacuum drying oven, and vacuum-dried at 50° C. for 4 hours to obtain the product powder, which is the transition metal phosphide described in the present invention.

The phase of the Ni ₂ P powder prepared in this example is shown in Fig. 6, from which it can be seen that the phase of the obtained Ni ₂ P powder is pure.

Embodiment 6:

First, mix and stir water and ethylene glycol at a volume ratio of 1:1, take 40mL and add it to the reaction kettle, then add 1.051g nickel sulfate (NiSO ₄ ·6H ₂ O), stir the solution until it becomes transparent, and then turn the solution to Add 0.31g of excess yellow phosphorus to the transparent solution, seal the lining into a stainless steel mold, raise it from room temperature to 140°C, and keep it warm for 12 hours; then cool to room temperature with the furnace , the obtained powder was washed with ethanol, benzene and distilled water 2-3 times respectively, placed in a vacuum drying oven, and vacuum-dried at 50° C. for 4 hours. The obtained product powder is the transition metal phosphide described in the present invention.

The phase of the Ni ₁₂ P ₅ powder prepared in this example is shown in Figure 7, from which it can be seen that the phase of the obtained Ni ₁₂ P ₅ powder is pure.

Embodiment 7:

First, mix and stir water and ethylene glycol according to the volume ratio of 1:1, take 40mL and add it to the reaction kettle, then add 0.525g nickel sulfate (NiSO ₄ ·6H ₂ O), stir the solution until it becomes transparent, then turn the solution to Add 0.31g of excess yellow phosphorus to the transparent solution, seal the lining into a stainless steel mold, raise it from room temperature to 160°C, and keep it warm for 12 hours; then cool it down to room temperature with the furnace , the obtained powder was washed with ethanol, benzene and distilled water 2-3 times respectively, placed in a vacuum drying oven, and vacuum-dried at 50° C. for 4 hours. The obtained product powder is the transition metal phosphide described in the present invention.

The phase of the Ni ₁₂ P ₅ powder prepared in this example is shown in Figure 8, from which it can be seen that the obtained Ni ₁₂ P ₅ powder has a pure phase.

In summary, the preparation method of the present invention is simple, and the raw materials used are widely available, and two kinds of nickel phosphide with different compositions and shapes can be prepared in the same solvent system: Ni ₂ P and Ni ₁₂ P ₅ , as shown in Figure 1 The pattern obtained by XRD analysis of the product Ni ₂ P prepared by the present invention, and Fig. 2 is the pattern obtained by XRD analysis of the product Ni ₁₂ P ₅ prepared by the present invention; Fig. ₃ (A) is the micro (B) is the photo of Ni ₂ P dendrites of the product of the present invention; (C) is the photo of Ni ₁₂ P ₅ microspheres of the product of the present invention; the results prove that: under 1:4 solvent ratio (ethylene di Alcohol and water) can be prepared to obtain nickel phosphide (Ni ₂ P) microcrystals, as shown in Figure 4 is the growth process of Ni ₂ P dendritic microcrystals of the product of the present invention. And by adjusting different temperatures (160-180 ℃), two kinds of crystals, hollow thorn ball and dendritic crystal, can be obtained; under the solvent ratio of 1:1 (ethylene glycol and water), hollow thorn ball-shaped nickel phosphide (Ni ₁₂ P ₅ ) microspheres; by adjusting the amount of nickel sulfate added and the content of ethylene glycol and water in the mixed solvent, the mutual transformation between different compositions of nickel phosphide (Ni ₂ P and Ni ₁₂ P ₅ ) can be realized.

Claims (2)

1. the preparation method of a transition metal phosphide is characterized in that, may further comprise the steps:

1) adding volume ratio in autoclave is 1: the ethylene glycol of (1～4) and water, and mixing and stirring solution adds the nickel salt of 0.01～0.03g in every ml soln, stir and dissolve, form clear solution fully until solid;

2) clear solution is changed in the polytetrafluoroethyllining lining, the yellow phosphorus that in every milliliter of clear solution, adds 0.005～0.02g, then polytetrafluoroethyllining lining is sealed in the stainless steel mould, in confined conditions by room temperature begin the heating and at 140-180 ℃ of reacting by heating 12h;

3) after reaction was finished, furnace cooling was used the fast quantification filter paper filtering then to room temperature, promptly gets crude product;

4) with benzene, ethanol and distilled water crude product is washed successively;

5) product after will washing is inserted in the vacuum drying oven, in 50 ℃ of following vacuum-drying 4h, obtains described transition metal phosphide.

2. the preparation method of transition metal phosphide according to claim 1 is characterized in that, described nickel salt is single nickel salt, nickelous chloride or nickelous nitrate.

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