Preparation process of multi-metal doped phosphorus selenide

Abstract

The invention discloses a preparation process of multi-metal doped phosphorus selenide. The preparation process comprises the following steps: step 1, preparing and mixing raw materials; 2, quartz tube pretreatment and raw material packaging; step 3, gradient calcination; the preparation method has the advantages that the composite metal phosphorus selenide (Fex (CoNiCuZn) 1-xPSe3) with gradient component distribution is prepared by regulating and controlling the molar ratio of Fe to Co, Ni to Cu to Zn (Fe: (Co + Ni + Cu + Zn) = 9: 1, 8: 2 and 7: 3) and combining a vacuum tube sealing high-temperature calcination process, the oxygen evolution reaction (OER) activity of the material is remarkably improved through the multi-metal synergistic effect and controllable lattice distortion optimization, and the composite metal phosphorus selenide can be used for preparing the composite metal phosphorus selenide (Fex (CoNiCuZn) 1-xPSe3) with gradient component distribution. The overpotential of the obtained catalyst under the current density of 10 mAcm <-2 > is as low as 322 mV and is close to commercial IrO2 (306 mV), the performance is excellent under the high current density of 100 mAcm <-2 >, the process is simple, the cost is low, the raw material cost is reduced by 90% or above compared with that of a noble metal catalyst, and a new strategy is provided for industrial application of the efficient OER catalyst.

Description

Technical Field

[0001] The present invention relates to the technical fields of multi-component alloys and semiconductor materials, and particularly to a preparation process of a multi-metal doped phosphoselenide. Background Art

[0002] As the anodic reaction of water electrolysis for hydrogen production, the slow kinetics of the electron transfer process in the oxygen evolution reaction leads to a high overpotential, which becomes a key bottleneck restricting the energy conversion efficiency. Traditional iron-based phosphoselenides, such as FePSe3, although having a layered structure and semiconductor properties, still have the following defects: the intrinsic catalytic activity of a single Fe active site is relatively low; the inherent electrical conductivity of the material is poor, and the charge transfer efficiency is limited; during the long-term electrolysis process, the structure is prone to collapse, resulting in a significant decrease in activity. In the prior art, although the doping of a single transition metal, such as Co or Ni, can partially improve the OER activity of FePSe3, it is difficult to achieve the synergistic catalytic effect of multiple active sites, and the regulation effect of trace doping on the electronic structure of the material is limited.

[0003] Although high-entropy alloy materials have the advantage of multi-metal synergy, their preparation processes are complex. For example, mechanical alloying is prone to introducing impurities, and chemical vapor deposition has a high cost. Moreover, existing research mainly focuses on equimolar multi-metal systems, lacking a systematic exploration of the main element gradient doping. Therefore, developing a preparation process of a multi-metal doped phosphoselenide is of great significance for breaking through the performance bottleneck of iron-based phosphoselenides. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: to provide a preparation process of a multi-metal doped phosphoselenide with high efficiency and a simple preparation method.

[0005] To solve the above technical problem, the present invention is solved by the following technical solutions: a preparation process of a multi-metal doped phosphoselenide, comprising the following steps:

[0006] Step 1, raw material preparation and mixing: Mix Fe powder with Co powder, Ni powder, Cu powder, and Zn powder according to a certain molar ratio, and then mix and grind them with red phosphorus and selenium powder according to a certain molar ratio in an argon glove box until uniform;

[0007] Step 2, quartz tube pretreatment and raw material encapsulation: Uniformly coat the inner wall of the quartz tube with an alumina-yttria composite nano-coating, dry it for standby, put the uniformly mixed raw materials into the quartz tube coated with the coating, first perform rough pumping with a vacuum pump to make the pressure in the tube reach 10 -1 Pa, then switch to a molecular pump for fine pumping to less than or equal to 3×10 -3 Pa, and then seal the tube orifice with a hydrogen-oxygen flame to ensure tightness;

[0008] Step 3: Gradient calcination: Put the sealed quartz tube into a muffle furnace with a set temperature gradient field, heat it up to 650 - 750 °C at a rate of 1 - 3 °C / min, calcine for 3 - 7 days, break the quartz tube after natural cooling to obtain a poly-metallic phosphoselenide bulk;

[0009] Step 4: Post-treatment: Put the bulk material into a ball mill, perform ball milling according to a certain ball-to-material ratio and ball milling time. After ball milling, transfer the powder to a container, add absolute ethanol, and carry out microwave-assisted cleaning. Set the microwave power and cleaning time, clean 3 times, and finally dry it in vacuum at 60 °C for 12 hours.

[0010] Preferably, in Step 1: Raw material preparation and mixing, the molar ratio of Fe powder to Co powder, Ni powder, Cu powder, and Zn powder is 1:1:1:1, and the molar ratio of Fe powder to Co powder, Ni powder, Cu powder, and Zn powder is x:(1 - x), where x = 0.9, 0.8, 0.7.

[0011] Preferably, in Step 1: Raw material preparation and mixing, the mixing ratio of Fe powder to Co powder, Ni powder, Cu powder, Zn powder to red phosphorus and selenium powder is 1:1:3 in molar ratio.

[0012] Preferably, in Step 1: Raw material preparation and mixing, the mixing and grinding time of Fe powder to Co powder, Ni powder, Cu powder, Zn powder with red phosphorus and selenium powder is 30 minutes.

[0013] Preferably, in Step 2: Quartz tube pretreatment and raw material encapsulation, the wall thickness of the quartz tube is 1 - 2 mm, the inner diameter is 10 mm, and the length is 150 mm.

[0014] Preferably, in Step 2: Quartz tube pretreatment and raw material encapsulation, the vacuum degree before sealing the quartz tube mouth is less than or equal to 3×10 -3 Pa.

[0015] Preferably, in Step 3: Gradient calcination, the calcination temperature is 650 - 750 °C, and the calcination time is 5 days.

[0016] Preferably, in Step 4: Post-treatment, the ball-to-material ratio is 5:1 - 10:1, and the ball milling time is 30 - 60 minutes.

[0017] Preferably, the application of the prepared poly-metallic phosphoselenide in the electrocatalytic water oxidation reaction catalyst is suitable for an alkaline electrolyte environment

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The raw materials selected for the multi-metal doped iron-based phosphoselenide provided by the present invention are economical. Common transition metal powders such as Fe, Co, Ni, Cu, Zn, red phosphorus, and selenium powder are used as raw materials. The cost is reduced by more than 90% compared with noble metal catalysts such as IrO2, and the raw materials are easily obtained, which is suitable for industrial applications.

[0020] 2. The preparation method is simple and controllable. The sealed tube method is combined with the gradient calcination process. The volatilization of selenium is suppressed by vacuum sealing to ensure uniform solid solution of elements. No complex equipment such as chemical vapor deposition system is required. The operation is simple and can be produced on a large scale.

[0021] 3. Through the multi-metal ratio regulation and lattice distortion optimization strategy, the overpotential of the oxygen evolution reaction is successfully reduced to 322 mV@10 mA / cm 2 , which is 34% lower than that of pure FePSe3 (491 mV) and comparable to that of commercial IrO2 (306 mV). The overpotential growth rate of this material at industrial-level high current density (such as >100 mA / cm 2 ) is significantly lower than that of IrO2, which can greatly reduce the energy consumption and equipment cost of electrolytic water hydrogen production. With its activity close to noble metal catalysts, better large-scale operation stability and low-cost advantages, this material is expected to be an ideal candidate to replace IrO2 / RuO2, providing an efficient and economical solution for large-scale green hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention.

[0023] Figure 1 It is the X-ray diffraction pattern of all materials and reference samples in the examples;

[0024] Figure 2 It is the transmission electron microscope image and energy spectrum diagram of the material obtained in Example 1;

[0025] Figure 3 It is the OER polarization curve diagram of all materials and reference samples in the examples. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] Unless otherwise clearly specified in the context, nouns without quantifiers and nouns modified by "the" include singular and plural referents.

[0027] As used in the specification and claims, the terms "comprising", "including", "having", "can", "containing" and variations thereof are open transitional phrases, terms or words that require the presence of the specified component / step and allow the presence of other components / steps. However, such descriptions should also be construed to describe the composition or method as "consisting of" and "consisting essentially of" the listed components / steps, which allows only the specified components / steps and any inevitable impurities that may result therefrom, and excludes other components / steps.

[0028] The numerical values in the specification and claims of this application should be understood to include the same numerical values when reduced to the same number of significant figures and numerical values that differ from the stated values by less than the experimental error of the conventional measurement techniques used to determine the values of the type described in this application.

[0029] All ranges disclosed herein include the indicated endpoints and can be combined independently (e.g., the range "2 grams to 10 grams" includes the endpoints 2 grams and 10 grams, and all intermediate values).

[0030] The terms "about" and "approximate" can be used to include any numerical value that can vary without changing the basic function of that value. When used with a range, "about" and "approximate" also disclose the range defined by the absolute values of the two endpoints. For example, "about 2 to about 4" also discloses the range "2 to 4". Generally, the terms "about" and "approximate" can refer to ±10% of the indicated number. However, for temperature, the term "about" means ±1°C.

[0031] Unless otherwise clearly specified, the percentages of the elements should be considered as weight percentages of the alloy.

[0032] This disclosure may relate to the temperature of certain method steps. It should be noted that these indicators generally refer to the temperature set by a heat source (such as a furnace), and not necessarily the temperature that the heated material must reach.

[0033] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be used in other embodiments, variations, improvements, equivalent schemes, and other technical schemes without departing from the spirit and scope of the present invention.

[0034] The present invention provides a preparation process for a multi-metal-doped phosphoselenide, comprising the following steps:

[0035] Step 1. Raw material preparation and mixing:

[0036] Weigh more than five kinds of transition metal powders with a purity of greater than or equal to 99%, red phosphorus with a purity of greater than or equal to 99.9%, and selenium powder with a purity of greater than or equal to 99.5% according to the molar ratios of Fe:(Co + Ni + Cu + Zn) = 9:1, 8:2, 7:3, and the molar ratio of total metal:phosphorus:selenium = 1:1:3. Place the raw materials in an argon glove box and mix and grind them for 30 minutes until uniform.

[0037] Step 2. Pretreatment of the quartz tube and encapsulation of the raw materials:

[0038] Uniformly coat the inner wall of the quartz tube with an alumina - yttria composite nano - coating and dry it for later use. Load the uniformly mixed raw materials into the quartz tube with the coated layer. The wall thickness of the quartz tube is 1 - 2 mm, the inner diameter is 10 mm, and the length is 150 mm. Connect to a vacuum system and pump it down to less than or equal to 10 -1 Pa, then switch to a molecular pump for fine pumping to less than or equal to 3×10 -3 Pa, ensure that the vacuum degree before sealing the mouth of the quartz tube is less than or equal to 3×10 -3 Pa, and then use a hydrogen - oxygen flame to seal the mouth of the tube to ensure airtightness.

[0039] Step 3. Gradient calcination:

[0040] Put the sealed quartz tube into a muffle furnace with a set temperature gradient field, heat it to 650 °C at a rate of 1 °C / min, hold for 5 days, then naturally cool to room temperature. After natural cooling, break the quartz tube to obtain a multi - metal phosphorus selenide bulk.

[0041] Step 4. Post - treatment:

[0042] Put the bulk material into a ball mill and perform ball - milling treatment according to a ball - to - material ratio of 5:1 - 10:1 and a ball - milling time of 30 - 60 minutes. After ball - milling, transfer the powder to a container, add anhydrous ethanol, perform microwave - assisted cleaning, set the microwave power and cleaning time, clean 3 times, and finally dry it in vacuum at 60 °C for 12 hours.

[0043] Specific steps are as follows: Weigh more than five kinds of transition metal powders with a purity of greater than or equal to 99%, red phosphorus with a purity of greater than or equal to 99.9%, and selenium powder with a purity of greater than or equal to 99.5% according to the molar ratios of Fe:(Co + Ni + Cu + Zn) = 9:1, 8:2, 7:3, and the molar ratio of total metal:phosphorus:selenium = 1:1:3. Place the raw materials in an argon glove box and mix and grind them for 30 minutes until uniform. Uniformly coat the inner wall of the quartz tube with an alumina - yttria composite nano - coating and dry it for later use. Load the uniformly mixed raw materials into the quartz tube with the coated layer. The wall thickness of the quartz tube is 1 - 2 mm, the inner diameter is 10 mm, and the length is 150 mm. Connect to a vacuum system and pump it down to less than or equal to 10 -1 Pa, then switch to a molecular pump for fine pumping to less than or equal to 3×10 -3Pa, ensure that the vacuum degree before sealing the orifice of the quartz tube is less than or equal to 3×10 -3 Pa, then use a hydrogen-oxygen flame to seal the orifice to ensure tightness. Place the sealed quartz tube into a muffle furnace with a set temperature gradient field, heat it to 650 °C at a rate of 1 °C / min, hold for 5 days, and then naturally cool to room temperature. After natural cooling, break the quartz tube to obtain a poly-metallic phosphoselenide bulk. Put the bulk material into a ball mill and perform ball milling treatment according to a ball-to-material ratio of 5:1 - 10:1 and a ball milling time of 30 - 60 minutes. After ball milling, transfer the powder to a container, add absolute ethanol, and perform microwave-assisted cleaning. Set the microwave power and cleaning time, and clean 3 times. Finally, dry it in vacuum at 60 °C for 12 hours.

[0044] Example 1. A preparation process of a multi-metal doped phosphoselenide, comprising the following steps:

[0045] Step 1. Raw material preparation and mixing:

[0046] Weigh 9 mmol of Fe powder, 0.25 mmol of Co powder, 0.25 mmol of Ni powder, 0.25 mmol of Cu powder, 0.25 mmol of Zn powder, 10 mmol of red phosphorus, and 30 mmol of selenium powder, and mix and grind them in an argon glove box for 30 minutes until uniform;

[0047] Step 2. Quartz tube pretreatment and raw material encapsulation:

[0048] Uniformly coat the inner wall of the quartz tube with an alumina-yttria composite nano-coating and dry it for standby. Load the uniformly mixed raw materials into the coated quartz tube. The wall thickness of the quartz tube is 1 - 2 mm, the inner diameter is 10 mm, and the length is 150 mm. Connect the vacuum system and pump it down to less than or equal to 10 -1 Pa, then switch to a molecular pump for fine pumping to less than or equal to 3×10 -3 Pa, ensure that the vacuum degree before sealing the orifice of the quartz tube is less than or equal to 3×10 -3 Pa, then use a hydrogen-oxygen flame to seal the orifice to ensure tightness;

[0049] Step 3. Gradient calcination:

[0050] Place the sealed tube in a muffle furnace, heat it to 650 °C at a rate of 1 °C / min, calcine for 6 days, and break the quartz tube after natural cooling to obtain a multi-metal doped iron-based phosphoselenide bulk;

[0051] Step 4. Post-treatment:

[0052] Grind the bulk into powder, add absolute ethanol, perform microwave-assisted cleaning, set the microwave power and cleaning time, clean 3 times, and finally dry it in vacuum at 60 °C for 12 hours. After drying, obtain the target product Fe 0.9 (CoNiCuZn)0.1 PSe3.

[0053] The specific steps are as follows: Weigh 9 mmol of Fe powder, 0.25 mmol of Co powder, 0.25 mmol of Ni powder, 0.25 mmol of Cu powder, 0.25 mmol of Zn powder, 10 mmol of red phosphorus and 30 mmol of selenium powder, mix and grind them in an argon glove box for 30 minutes until uniform. Uniformly coat the inner wall of the quartz tube with an alumina-yttrium oxide composite nano-coating, dry it for standby. Load the uniformly mixed raw materials into the coated quartz tube. The wall thickness of the quartz tube is 1 - 2 mm, the inner diameter is 10 mm, and the length is 150 mm. Connect the vacuum system and pump it down to less than or equal to 10 -1 Pa, then change to a molecular pump for fine pumping to less than or equal to 3×10 -3 Pa, ensure that the vacuum degree before sealing the mouth of the quartz tube is less than or equal to 3×10 -3 Pa, then use a hydrogen-oxygen flame to seal the mouth of the tube to ensure airtightness. Place the sealed tube in a muffle furnace, heat it to 650 °C at a rate of 1 °C / min, calcine it for 6 days, naturally cool it, and then break the quartz tube to obtain a multi-metal doped iron-based phosphoselenide bulk. Grind the bulk into powder, add anhydrous ethanol, and perform microwave-assisted cleaning. Set the microwave power and cleaning time, and clean it 3 times. Finally, dry it in vacuum at 60 °C for 12 hours. After drying, the target product Fe 0.9 (CoNiCuZn) 0.1 PSe3 is obtained. As Figure 1 shown, the diffraction peaks of Example 1 match those of the reference sample FePSe3, and no impurity peaks appear, indicating the successful synthesis of a single phase. As the doping ratio of metal elements increases, the positions of the diffraction peaks shift towards lower angles, which reflects the fine-tuning effect of the doping elements on the crystal structure of the material, causing slight lattice distortion, which will have a certain impact on the electrochemical performance of this material. As Figure 2 shown in a, the surface of the material in Example 1 has clear nanosheet structure characteristics. Figure 2 The electron diffraction pattern in b shows the crystal structure of this material. Figure 2 c indicates that it has good crystal quality. Through the element distribution map, Figure 2 from d to Figure 2 k, it can be observed that the elements of iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), phosphorus (P) and selenium (Se) are evenly distributed in the material, and there is no obvious aggregation phenomenon among the elements, indicating that these elements are evenly distributed in this material, with good structural stability and dispersibility. Under a three-electrode system, using 1 mol / L potassium hydroxide solution as the electrolyte, Hg / HgO as the reference electrode, and a graphite rod as the counter electrode, the carbon paper loaded with Fe 0.9 (CoNiCuZn) 0.1 PSe3 is used as the working electrode to test its electrochemical OER performance asFigure 3 As shown, in 1 M KOH, Fe 0.9 (CoNiCuZn) 0.1 PSe3 has an overpotential of 351 mV at 10 mA cm -2 .

[0054] Example 2. A preparation process of a multi-metal doped phosphorus selenide, comprising the following steps:

[0055] Step 1. Raw material preparation and mixing:

[0056] Weigh 8 mmol of Fe powder, 0.5 mmol of Co powder, 0.5 mmol of Ni powder, 0.5 mmol of Cu powder, 0.5 mmol of Zn powder, 10 mmol of red phosphorus and 30 mmol of selenium powder. Place the raw materials in an argon glove box and mix and grind them for 30 minutes until homogeneous;

[0057] Step 2. Quartz tube pretreatment and raw material encapsulation:

[0058] Uniformly coat the inner wall of the quartz tube with an alumina-yttria composite nano-coating and dry it for later use. Load the uniformly mixed raw materials into the quartz tube coated with the coating. The wall thickness of the quartz tube is 1-2 mm, the inner diameter is 10 mm, and the length is 150 mm. Connect the vacuum system and pump it down to less than or equal to 10 -1 Pa, and then switch to a molecular pump for fine pumping to less than or equal to 3×10 -3 Pa. Ensure that the vacuum degree before sealing the quartz tube is less than or equal to 3×10 -3 Pa, and then use a hydrogen-oxygen flame to seal the tube mouth to ensure airtightness;

[0059] Step 3. Gradient calcination:

[0060] Put the sealed quartz tube into a muffle furnace with a set temperature gradient field, heat it to 650 °C at a rate of 1 °C / min, calcine for 6 days, and then naturally cool to room temperature. After natural cooling, break the quartz tube to obtain a multi-metal doped iron-based phosphorus selenide bulk;

[0061] Step 4. Post-treatment:

[0062] Grind the bulk into powder, add absolute ethanol, and perform microwave-assisted cleaning. Set the microwave power and cleaning time, clean 3 times, and finally dry it in vacuum at 60 °C for 12 hours. After drying, obtain the target product Fe 0.8 (CoNiCuZn) 0.2 PSe3.

[0063] The specific steps are as follows: Weigh 8 mmol of iron powder, 0.5 mmol of cobalt powder, 0.5 mmol of nickel powder, 0.5 mmol of copper powder, 0.5 mmol of zinc powder, 10 mmol of red phosphorus and 30 mmol of selenium powder. Place the raw materials in an argon glove box and mix and grind them for 30 minutes until uniform. Uniformly coat the inner wall of the quartz tube with an alumina-yttria composite nanocoating, dry it for later use. Load the uniformly mixed raw materials into the coated quartz tube. The wall thickness of the quartz tube is 1 - 2 mm, the inner diameter is 10 mm, and the length is 150 mm. Connect the vacuum system and pump it down to less than or equal to 10 -1 Pa, and then switch to a molecular pump for fine pumping to less than or equal to 3×10 -3 Pa. Ensure that the vacuum degree before sealing the mouth of the quartz tube is less than or equal to 3×10 -3 Pa. Then use a hydrogen-oxygen flame to seal the mouth of the tube to ensure airtightness. Put the sealed quartz tube into a muffle furnace with a set temperature gradient field, heat it to 650 °C at a rate of 1 °C / min, calcine for 6 days, and then naturally cool to room temperature. After natural cooling, break the quartz tube to obtain a multi-metal doped iron-based phosphorus selenide bulk. Grind the bulk into powder, add absolute ethanol, and perform microwave-assisted cleaning. Set the microwave power and cleaning time, and clean 3 times. Finally, dry it in vacuum at 60 °C for 12 hours. After drying, obtain the target product Fe 0.8 (CoNiCuZn) 0.2 PSe3. Under a three-electrode system, use a 1 mol / L potassium hydroxide solution as the electrolyte, a Hg / HgO as the reference electrode, a graphite rod as the counter electrode, and a carbon paper loaded with Fe 0.8 (CoNiCuZn) 0.2 PSe3 as the working electrode, and test its electrochemical performance as Figure 3 shown, showing that its OER overpotential is 325 mV (10 mA cm -2 ).

[0064] Example 3. A preparation process of a multi-metal doped phosphorus selenide, comprising the following steps:

[0065] Step 1. Raw material preparation and mixing:

[0066] Weigh 7 mmol of iron powder, 0.75 mmol of cobalt powder, 0.75 mmol of nickel powder, 0.75 mmol of copper powder, 0.75 mmol of zinc powder, 10 mmol of red phosphorus and 30 mmol of selenium powder. Place the raw materials in an argon glove box and mix and grind them for 30 minutes until uniform;

[0067] Step 2. Quartz tube pretreatment and raw material encapsulation:

[0068] A composite nano - coating of alumina - yttrium oxide is evenly coated on the inner wall of the quartz tube and dried for later use. The uniformly mixed raw materials are loaded into the quartz tube with the coated coating. The wall thickness of the quartz tube is 1 - 2 mm, the inner diameter is 10 mm, and the length is 150 mm. Connect the vacuum system and pump it down to less than or equal to 10 -1 Pa, and then switch to a molecular pump for fine pumping to less than or equal to 3×10 -3 Pa. Ensure that the vacuum degree before sealing the mouth of the quartz tube is less than or equal to 3×10 -3 Pa, and then use a hydrogen - oxygen flame to seal the mouth of the tube to ensure airtightness;

[0069] Step Three: Gradient calcination:

[0070] Put the sealed quartz tube into a muffle furnace with a set temperature gradient field, heat it up to 650 °C at a rate of 1 °C / min, calcine for 6 days, naturally cool it, and then break the quartz tube to obtain a multi - metal - doped iron - based phosphoselenide bulk;

[0071] Step Four: Post - treatment:

[0072] Grind the bulk into powder, add absolute ethanol, and carry out microwave - assisted cleaning. Set the microwave power and cleaning time, clean 3 times, and finally dry it in vacuum at 60 °C for 12 hours. After drying, the target product Fe 0.7 (CoNiCuZn) 0.3 PSe3 is obtained.

[0073] Specific steps are as follows: Weigh 7 mmol of Fe powder, 0.75 mmol of Co powder, 0.75 mmol of Ni powder, 0.75 mmol of Cu powder, 0.75 mmol of Zn powder, 10 mmol of red phosphorus and 30 mmol of selenium powder. Place the raw materials in an argon glove box and mix and grind them for 30 minutes until uniform. A composite nano - coating of alumina - yttrium oxide is evenly coated on the inner wall of the quartz tube and dried for later use. The uniformly mixed raw materials are loaded into the quartz tube with the coated coating. The wall thickness of the quartz tube is 1 - 2 mm, the inner diameter is 10 mm, and the length is 150 mm. Connect the vacuum system and pump it down to less than or equal to 10 -1 Pa, and then switch to a molecular pump for fine pumping to less than or equal to 3×10 -3 Pa. Ensure that the vacuum degree before sealing the mouth of the quartz tube is less than or equal to 3×10 -3 Pa, and then use a hydrogen - oxygen flame to seal the mouth of the tube to ensure airtightness. Put the sealed quartz tube into a muffle furnace with a set temperature gradient field, heat it up to 650 °C at a rate of 1 °C / min, calcine for 6 days, naturally cool it, and then break the quartz tube to obtain a multi - metal - doped iron - based phosphoselenide bulk. Grind the bulk into powder, add absolute ethanol, and carry out microwave - assisted cleaning. Set the microwave power and cleaning time, clean 3 times, and finally dry it in vacuum at 60 °C for 12 hours. After drying, the target product Fe 0.7 (CoNiCuZn) 0.3PSe3, in a three - electrode system, with 1 mol / L potassium hydroxide solution as the electrolyte, Hg / HgO as the reference electrode, a graphite rod as the counter electrode, and carbon paper loaded with Fe 0.7 (CoNiCuZn) 0.3 PSe3 as the working electrode, to test its electrochemical performance as Figure 3 shown, showing that its OER overpotential is 322 mV (10 mA cm -2 ). As the doping ratio increases, the overpotential further decreases, indicating that the multi - metal synergistic effect significantly accelerates the reaction kinetics.

[0074] Those skilled in the art should understand that the embodiments of the present invention shown in the above description are only examples and do not limit the present invention. The object of the present invention has been fully and effectively achieved. The functions and structural principles of the present invention have been shown and described in the embodiments. Without departing from the said principles, the embodiments of the present invention can have any deformation or modification. Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. This specific embodiment is only an interpretation of the present application and does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment as needed after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. Preparation process of a multi-metal doped phosphorus selenide, characterized in that: It includes the following steps: Step 1. Raw material preparation and mixing: Mix Fe powder with Co powder, Ni powder, Cu powder, and Zn powder according to a certain molar ratio, and then mix and grind them with red phosphorus and selenium powder in an argon glove box according to a certain molar ratio until uniform; Step 2. Pretreatment of quartz tube and encapsulation of raw materials: Uniformly coat the inner wall of the quartz tube with an alumina-yttrium oxide composite nano-coating, dry it for standby, load the uniformly mixed raw materials into the quartz tube coated with the coating, first conduct rough pumping with a vacuum pump to make the pressure in the tube reach 10- 1 Pa, then switch to a molecular pump for fine pumping until it is less than or equal to 3×10-3 Pa, and then use a hydrogen-oxygen flame to seal the tube mouth to ensure tightness; Step 3. Gradient calcination: Put the sealed quartz tube into a muffle furnace with a set temperature gradient field, heat it to 650 - 750 °C at a rate of 1 - 3 °C / min, calcine for 3 - 7 days, break the quartz tube after natural cooling to obtain a poly-metallic phosphoselenide bulk; Step 4. Post-treatment: Put the bulk material into a ball mill, perform ball milling according to a certain ball-to-material ratio and ball milling time. After ball milling, transfer the powder to a container, add absolute ethanol, and perform microwave-assisted cleaning. Set the microwave power and cleaning time, clean 3 times, and finally dry it in vacuum at 60 °C for 12 hours.

2. The preparation process of a multi-metal doped phosphorus selenide according to claim 1, characterized in that: In the Step 1. Raw material preparation and mixing, the molar ratio of Fe powder to Co powder, Ni powder, Cu powder, and Zn powder is 1:1:1:1, and the molar ratio of Fe powder to Co powder, Ni powder, Cu powder, and Zn powder is x:(1 - x), where x = 0.9, 0.8, 0.

7.

3. The preparation process of a multi-metal doped phosphoselenide according to claim 1, characterized in that: In the Step 1. Raw material preparation and mixing, the mixing ratio of Fe powder to Co powder, Ni powder, Cu powder, and Zn powder with red phosphorus and selenium powder is 1:1:3 in molar ratio.

4. The preparation process of a multi-metal doped phosphorus selenide according to claim 1, characterized in that: In the Step 1. Raw material preparation and mixing, the mixing and grinding time of Fe powder to Co powder, Ni powder, Cu powder, and Zn powder with red phosphorus and selenium powder is 30 minutes.

5. The preparation process of a multi-metal doped phosphorus selenide according to claim 1, characterized in that: In the Step 2. Quartz tube pretreatment and raw material encapsulation, the wall thickness of the quartz tube is 1 - 2 mm, the inner diameter is 10 mm, and the length is 150 mm.

6. The preparation process of a multi-metal doped phosphoselenide according to claim 1, characterized in that: In the Step 2. Quartz tube pretreatment and raw material encapsulation, the vacuum degree before sealing the quartz tube mouth is less than or equal to 3×10-3 Pa.

7. The preparation process of a multi-metal doped phosphorus selenide according to claim 1, characterized in that: In the Step 3. Gradient calcination, the calcination temperature is 650 - 750 °C, and the calcination time is 5 days.

8. The preparation process of a multi-metal doped phosphorus selenide according to claim 1, characterized in that: In the Step 4. Post-treatment, the ball-to-material ratio is 5:1 - 10:1, and the ball milling time is 30 - 60 minutes.

9. The preparation process of a multi-metal doped phosphorus selenide according to any one of claims 1-8, characterized in that: Application of the prepared poly-metallic phosphoselenide in an electrocatalytic water oxidation reaction catalyst, which is applicable to an alkaline electrolyte environment.

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