A nano high-entropy phosphide / carbon composite material and a preparation method thereof

Abstract

The application discloses a kind of nano high-entropy phosphide / carbon composite material and preparation method thereof, comprising the following operating steps: (1) phosphorus-containing resin is soaked into acid solution to adjust the pH of phosphorus-containing resin, and is crushed after drying;(2) water is added to stir thoroughly, to obtain a mixture, Fe salt, Co salt, Ni salt, Cu salt and Mo salt solution are mixed uniformly and then added to the mixture, denoted as M + Resin;(3) enter alkaline substance grinding, heat treatment, after reaction is finished, to obtain nano high-entropy phosphide / carbon composite material.The method of the application uses phosphorus-containing resin as raw material, and the used resin is green and environmentally friendly, low in price, low in raw material and preparation cost;The method of the application is simple in operation, and the particle size of the prepared nano high-entropy phosphide / carbon composite material reaches nanoscale, and the particle size is controllable.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a phosphide / carbon composite material, in particular to a nano high-entropy phosphide / carbon composite material and a preparation method thereof. BACKGROUND

[0002] Single-component electrocatalysts, such as metal oxides, metal sulfides and the like, show limited catalytic activity in the electrocatalytic process due to the simple composition and structure. In recent years, single-phase multi-component high-entropy materials have multiple metal active centers and structural disorder, and show significant catalytic activity and fast redox reaction kinetics. Among them, high-entropy alloys, high-entropy oxides and high-entropy sulfides have been widely used in the fields of electrochemical energy storage and catalysis. However, the synthesis process of the high-entropy material is relatively complex, the cost is high, and the high-entropy material prepared is often in the form of irregular blocks with micron or even larger sizes. Therefore, it is still a challenge to develop a simple and efficient preparation method to synthesize nano high-entropy materials.

[0003] The phosphorus element in the transition metal phosphide has metallic properties and can adjust the electronic structure of the phosphide, so the phosphide usually shows metalloid characteristics and high catalytic activity. In order to further optimize the composition and structure of the phosphide and improve the catalytic activity of the redox reaction, synthesizing high-entropy phosphide is a challenging and meaningful strategy. At present, the synthesis methods of high-entropy phosphide mainly include eutectic solvent method, hydrothermal / solvothermal method, sol-gel method and high-temperature solid phase method, and even multiple methods need to be combined. Generally, these high-entropy phosphide particles have large sizes, and need to be further loaded on carbon-based materials to meet the demand of electrocatalysts. Therefore, it is of important research value and economic benefit to develop a preparation method with low cost, easy operation and large-scale production to synthesize nano high-entropy phosphide / carbon composite materials for efficient electrocatalytic materials in one step. SUMMARY

[0004] Based on the deficiencies of the prior art, the application provides a nano high-entropy phosphide / carbon composite material and a preparation method thereof, which uses relatively low-cost raw materials to obtain a nano high-entropy phosphide / carbon composite material with low cost, easy operation and green environmental protection. The obtained nano high-entropy phosphide particles have nano sizes and are uniformly distributed in the layered porous carbon.

[0005] To achieve the above object, the technical scheme provided by the application is as follows:

[0006] A nano high-entropy phosphide / carbon composite material, the general formula of the nano high-entropy phosphide / carbon composite material is Nano-(Fe a Co b Ni c Cu d Mo e)2P / C, wherein each subscript value range is a is 0.25-0.3, b is 0.25, c is 0.25, d is 0.1-0.13, e is 0.1-0.12; the nano high-entropy phosphide / carbon composite material has high and stable catalytic performance.

[0007] The preparation method of the nano high-entropy phosphide / carbon composite material as described above comprises the following operation steps:

[0008] (1) Soak the phosphorus-containing resin into an acid solution to adjust the pH of the phosphorus-containing resin, dry after vacuum filtration, and then crush;

[0009] (2) Take the crushed phosphorus-containing resin obtained in step (1) and place it in a beaker, then add deionized water and stir thoroughly to obtain a mixture, mix the Fe salt, Co salt, Ni salt, Cu salt and Mo salt solutions uniformly and add them to the mixture, constant temperature magnetic stirring, vacuum filtration and drying to obtain a precursor resin containing five elements of Fe, Co, Ni, Cu and Mo, denoted as M + resin;

[0010] (3) Place the M + resin obtained in step (2) in a mortar, add a basic substance and grind thoroughly, perform a one-step heat treatment under a protective gas, after the reaction is completed, naturally cool, wash the obtained substance after heat treatment with deionized water until neutral, and dry to obtain a nano high-entropy phosphide / carbon composite material.

[0011] Preferably, the phosphorus-containing resin in step (1) is LXP-P01 resin.

[0012] Preferably, the acid solution in step (1) is one of hydrochloric acid solution, nitric acid solution or acetic acid solution; the concentration of the acid solution is 0.5-2.5 mol / L.

[0013] Preferably, the pH adjustment in step (1) is adjusted to a pH value of 5-7, preferably 6; after vacuum filtration, dry at 60°C until the moisture content is not more than 8wt%, and then crush.

[0014] Preferably, in step (2), 5mL of deionized water is added per gram of phosphorus-containing resin.

[0015] Preferably, the Fe salt, Co salt, Ni salt, Cu salt and Mo salt solution in step (2) is added in an amount of 50 mL; the Fe salt is ferric chloride (FeCl3) with a concentration of 0.2-0.6 mol / L, preferably 0.6 mol / L; the Co salt is cobalt chloride (CoCl2) with a concentration of 0.2-0.6 mol / L, preferably 0.5 mol / L; the Ni salt is nickel chloride (NiCl2) with a concentration of 0.2-0.6 mol / L, preferably 0.5 mol / L; the Cu salt is copper chloride (CuCl2) with a concentration of 0.2-0.6 mol / L, preferably 0.2 mol / L; and the Mo salt is molybdenum pentachloride (MoCl5) with a concentration of 0.2-0.6 mol / L, preferably 0.2 mol / L.

[0016] Preferably, after vacuum filtration in step (2), complete drying is performed at 60°C; and the drying in step (3) is complete drying at 60°C.

[0017] Preferably, the constant temperature magnetic stirring in step (2) is performed at a temperature of 50-65°C, a stirring rate of 300 rpm and for 3-6 h; preferably at 55°C, 300 rpm and for 4 h.

[0018] Preferably, the basic substance in step (3) is one of potassium hydroxide or sodium hydroxide, preferably potassium hydroxide; and the protective gas in step (3) is N2 or Ar atmosphere, preferably N2.

[0019] Preferably, the M + The resin is added in an amount of 1-3 g; the M + The resin is preferably added in an amount of 2 g; the M + The mass ratio of the resin to the basic substance is 1:0.05-0.4 (preferably 1:0.25-0.4).

[0020] Preferably, the one-step heat treatment in step (3) is performed at a temperature rising rate of 5-10°C / min to 750-1050°C and for 1-3 h; the temperature rising rate is preferably 5°C / min; and the holding time is preferably 1 h.

[0021] Compared with the prior art, the present application has the following advantages:

[0022] The method of the present application uses a phosphorus-containing resin as raw material, and the resin is green and environmentally friendly, low in price, and low in raw material and preparation cost; the method is simple to operate, and the prepared nano high-entropy phosphide / carbon composite material has a particle size of nanoscale and the particle size is controllable; the nano high-entropy phosphide / carbon composite material Nano-(Fe a Co b Ni cCu d Mo e )2P / C in the electrocatalytic sulfur reduction reaction shows excellent catalytic capacity; nano-high-entropy phosphide / carbon composite material Nano-(Fe a Co b Ni c Cu d Mo e )2P / C as a lithium-sulfur battery positive electrode catalyst shows stable and efficient electrocatalytic activity. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is the SEM photo of the nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared in Example 1 of the present application.

[0024] Figure 2 is the EDS photo of the nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared in Example 1 of the present application.

[0025] Figure 3 is the S8 reduction LSV performance curve of the nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared in Example 1 of the present application.

[0026] Figure 4 is the LSV performance curve of hydrogen evolution reaction (HER) of the nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared in Example 1 of the present application.

[0027] Figure 5 is the S8 reduction LSV performance curve of the nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10Electrochemical cycle performance curve of 2P / C applied to lithium-sulfur battery positive electrode catalyst.

[0028] Figure 6 SEM image of Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared by the present application comparative example 1.

[0029] Figure 7 LSV performance curve of S8 reduction of Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared by the present application comparative example 1.

[0030] Figure 8 LSV performance curve of HER of Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared by the present application comparative example 1. DETAILED DESCRIPTION

[0031] The present application will be described in detail below with reference to specific embodiments, but it should be understood that the scope of protection of the present application is not limited by the specific embodiments. The raw materials and reagents used in the examples are commercially available unless otherwise specified. The phosphorus-containing resin used in the examples is resin LXP-P01 purchased from Xi'an Lanxiao Science and Technology New Material Co., Ltd. (Lanxiao Science and Technology Sunresin).

[0032] Example 1

[0033] A method for preparing a nano-high-entropy phosphide / carbon composite material, the operation steps are as follows:

[0034] (1) 300 g of phosphorus-containing resin is soaked in a nitric acid solution with a concentration of 0.5 mol / L to adjust the pH value of the resin to 6, vacuum filtration, and then dried at 60°C until the moisture content is not more than 8 wt%, and then put into a pulverizer for crushing;

[0035] (2) Take 20g of the phosphorus-containing resin obtained after pulverization in step (1) and place it in a beaker. Then add 100mL of deionized water and stir thoroughly to obtain a mixture. Mix 50mL of FeCl3·6H2O solution (0.6mol / L), 50mL of CoCl2·6H2O solution (0.5mol / L), 50mL of NiCl2·6H2O solution (0.5mol / L), 50mL of CuCl2·2H2O solution (0.2mol / L), and 50mL of MoCl5 solution (0.2mol / L) evenly and add them to the mixture obtained above. Maintain a constant temperature of 55℃ and a stirring speed of 300rpm for 4h with magnetic stirring. After vacuum filtration, dry completely at 60℃ to obtain a precursor resin containing five metal elements: Fe, Co, Ni, Cu, and Mo, denoted as M. + Resin;

[0036] (3) Take the M obtained in step (2) + 2g of resin was placed in a mortar and pestle, and then... + The resin and potassium hydroxide were mixed at a mass ratio of 1:0.4. 0.8 g of potassium hydroxide was added and the mixture was thoroughly ground for 30 min. Then, under a nitrogen atmosphere, the temperature was increased to 1000℃ at a rate of 5℃ / min and held for 1 h for a one-step heat treatment. After the reaction was completed, the mixture was allowed to cool naturally. The resulting material was washed with deionized water until neutral and then completely dried at 60℃ to obtain the nano-high entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C.

[0037] Example 2

[0038] A method for preparing a nano-high-entropy phosphide / carbon composite material, comprising the following steps:

[0039] (1) Soak 300g of phosphorus-containing resin in a 0.5mol / L nitric acid solution to adjust the pH value of the resin to 6, filter it under vacuum, dry it at 60°C until the moisture content does not exceed 8%, and then put it into a pulverizer to pulverize it.

[0040] (2) Take 20g of the phosphorus-containing resin obtained after pulverization in step (1) and place it in a beaker. Then add 100mL of deionized water and stir thoroughly to obtain a mixture. Mix 50mL of FeCl3·6H2O solution (0.4mol / L), 50mL of CoCl2·6H2O solution (0.4mol / L), 50mL of NiCl2·6H2O solution (0.4mol / L), 50mL of CuCl2·2H2O solution (0.2mol / L), and 50mL of MoCl5 solution (0.2mol / L) evenly and add them to the mixture. Maintain a constant temperature of 55℃ and a stirring speed of 300rpm for 4h with magnetic stirring. After vacuum filtration, dry completely at 60℃ to obtain a precursor resin containing five metal elements: Fe, Co, Ni, Cu, and Mo, denoted as M. + Resin;

[0041] (3) Take the M obtained in step (2) + 2g of resin was placed in a mortar and pestle, and then... + The resin and potassium hydroxide were mixed at a mass ratio of 1:0.3. 0.6 g of potassium hydroxide was added and the mixture was thoroughly ground for 30 min. Then, under a N2 atmosphere, the temperature was increased to 900℃ at a rate of 5℃ / min and held for 1.5 h for a one-step heat treatment. After the reaction was completed, the mixture was allowed to cool naturally. The resulting material was washed with deionized water until neutral and then completely dried at 60℃ to obtain the nano-high entropy phosphide / carbon composite material Nano-(Fe 0.25 Co 0.25 Ni 0.25 Cu 0.13 Mo 0.12 )2P / C

[0042] Example 3

[0043] A method for preparing a nano-high-entropy phosphide / carbon composite material, comprising the following steps:

[0044] (1) Soak 300g of phosphorus-containing resin in a 0.5mol / L nitric acid solution to adjust the pH value of the resin to 7, filter under vacuum, dry at 60°C until the moisture content does not exceed 8%, and then put it into a pulverizer to pulverize.

[0045] (2) Take 40g of the phosphorus-containing resin obtained after pulverization in step (1) and place it in a beaker. Then add 100mL of deionized water and stir thoroughly to obtain a mixture. Mix 50mL of FeCl3·6H2O solution (0.6mol / L), 50mL of CoCl2·6H2O solution (0.5mol / L), 50mL of NiCl2·6H2O solution (0.5mol / L), 50mL of CuCl2·2H2O solution (0.2mol / L), and 50mL of MoCl5 solution (0.2mol / L) evenly and add them to the mixture. Maintain a constant temperature of 65℃ and a stirring speed of 300rpm for 4h with magnetic stirring. After vacuum filtration, dry completely at 60℃ to obtain a precursor resin containing five metal elements: Fe, Co, Ni, Cu, and Mo, denoted as M. + Resin;

[0046] (3) Take the M obtained in step (2) + 1g of resin was placed in a mortar and pestle, and then... + The resin and potassium hydroxide were mixed at a mass ratio of 1:0.05. 0.05 g of potassium hydroxide was added and the mixture was thoroughly ground for 30 min. Then, under a N2 atmosphere, the temperature was increased to 800℃ at a rate of 5℃ / min and held for 1.5 h for a one-step heat treatment. After the reaction was completed, the mixture was allowed to cool naturally. The resulting material was washed with deionized water until neutral and then completely dried at 60℃ to obtain the nano-high entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C.

[0047] Example 4

[0048] A method for preparing a nano-high-entropy phosphide / carbon composite material, comprising the following steps:

[0049] (1) Soak 300g of phosphorus-containing resin in a 0.5mol / L nitric acid solution to clean and adjust the pH value to 7, filter, dry and then pulverize;

[0050] (2) Take the phosphorus-containing resin 30 g obtained after crushing in step (1) and place it in a beaker, then add 100 mL of deionized water and stir thoroughly to obtain a mixture. Mix a 0.6 mol / L, 50 mL FeCl3·6H2O solution, a 0.5 mol / L, 50 mL CoCl2·6H2O solution, a 0.5 mol / L, 50 mL NiCl2·6H2O solution, a 0.2 mol / L, 50 mL CuCl2·2H2O solution, and a 0.2 mol / L, 50 mL MoCl5 solution uniformly, and then add them to the mixture. Keep the temperature at 55°C and the stirring rate at 300 rpm for constant temperature magnetic stirring for 5 h. Dry by suction filtration to obtain a precursor resin containing five metal elements Fe, Co, Ni, Cu, and Mo, denoted as M + resin;

[0051] (3) Take 3 g of the M + resin obtained in step (2) and place it in a mortar. Add 0.6 g of sodium hydroxide according to a mass ratio of M + resin to sodium hydroxide of 1:0.2, and grind thoroughly for 30 min. Then heat to 1000°C at a heating rate of 5°C / min under N2 atmosphere, and perform one-step heat treatment for 1 h. After the reaction is completed, naturally cool, wash the obtained substance with deionized water until neutral, and completely dry at 60°C to obtain a nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C.

[0052] Comparative Example 1

[0053] A method for preparing a nano-high-entropy phosphide / carbon composite material, the operation steps being as follows:

[0054] (3) Take 2 g of the M + resin obtained in step (2), and heat to 1000°C at a heating rate of 5°C / min under N2 atmosphere, and perform one-step heat treatment for 1 h. After the reaction is completed, naturally cool, wash the obtained substance with deionized water until neutral, and completely dry at 60°C to obtain a nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C.

[0055] The remaining operations are the same as in Example 1.

[0056] Figures 3-4 、 Figures 7-8 Preparation of C appearing in the above:

[0057] Operation steps: (1) 300 g of phosphorus-containing resin was soaked in a nitric acid solution with a concentration of 0.5 mol / L to adjust the pH value of the resin to 6, vacuum filtration was performed, and then drying was performed at 60°C until the moisture content was not more than 8 wt%, and then the phosphorus-containing resin was crushed in a pulverizer;

[0058] (2) 2 g of the phosphorus-containing resin obtained after crushing in step (1) was placed in a mortar, 0.8 g of potassium hydroxide was added, and grinding was performed for 30 min, then one-step heat treatment was performed at a temperature increasing rate of 5°C / min to 1000°C under N2 atmosphere, and after the reaction was completed, natural cooling was performed, the material obtained after heat treatment was washed with deionized water until neutral, and complete drying was performed at 60°C to obtain C, which was used as prepared.

[0059] Performance detection

[0060] 1. S8 reduction linear sweep voltammetry (LSV) test: 5 mg of sample was dispersed by ultrasonic and dropped in the middle of a glassy carbon electrode, 4 mM S8 and 1.0 M lithium bis(trifluoromethanesulfonyl)imide (LITFSI) were dissolved in 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL) solvents to prepare a mixed solution with a volume ratio of 1:1 as an electrolyte, and the electrocatalytic sulfur reduction capacity of the catalyst was tested on an electrochemical workstation. The samples tested were the nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared in Example 1, the above prepared C, the nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared in Comparative Example 1.

[0061] 2. Hydrogen evolution reaction (HER) linear sweep voltammetry (LSV) test: before testing, H2 was passed for 30 minutes to saturate the solution, and H2 was continuously passed during the test to ensure a gas-saturated environment. In addition, before performing the LSV test, CV cycle activation was performed for more than 20 cycles to stabilize the curve. In the LSV test, the voltage scanning range was 0.3 to -0.1 V (vs. RHE), the scanning speed was 5 mV s -1 , and the rotation speed was 400 rpm. The samples tested were the nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25Ni 0.25 Cu 0.10 Mo 0.10 )2P / C, the above-mentioned spare C, commercially available Pt / C, the nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C.

[0062] 3. Constant current charge-discharge cycle test: the sample is mixed with sublimed sulfur at a mass ratio of 1:3 and then uniformly reacted at 155°C for 12h. After cooling, conductive carbon black (Super-P) and polyvinylidene fluoride (PVDF) are added at a mass ratio of 8:1:1, fully ground, then N-methyl pyrrolidone is added dropwise to form a slurry, which is coated on an aluminum foil, vacuum dried, and then cut into a circular piece with a diameter of 14mm, which is the positive electrode (Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C@S or C@S), on a new wei battery test system, the assembled button cell is subjected to constant current charge-discharge in a voltage window of 1.7-2.8V for testing. The tested samples are respectively the nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C, the above-mentioned spare C.

[0063] The nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared in Example 1 and the composite material prepared in Comparative Example 1 are subjected to scanning electron microscope (SEM) and linear sweep voltammetry (LSV) tests. The nano-high-entropy phosphide / carbon composite material Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C prepared in Example 1 is used as a lithium-sulfur battery positive electrode catalyst for electrochemical cycle test analysis, as shown in Figures 1-8

[0064] From the SEM spectrum of Figure 1 , it can be seen that the nano-high-entropy phosphide particles Nano-(Fe​0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P are uniformly anchored in hierarchical porous carbon.

[0065] From the EDS spectrum of Nano-(Fe Figure 2 Co 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 Mo 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P, Fe, Co, Ni, Cu, Mo and P elements are uniformly distributed in nanoparticles without element segregation.

[0066] From the S8 reduction linear sweep voltammetry (LSV) test of Nano-(Fe Figure 3 Co 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C catalyst shows earlier half-wave potential (E half-wave ) and larger diffusion current intensity (J D ) in electrocatalytic sulfur reduction reaction, showing its excellent catalytic performance.

[0067] Figure 4 Results show that Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C catalyst in 1M KOH shows the best HER activity, only 224mV overpotential is needed to reach 100mA cm -2 , close to Pt / C catalyst, showing excellent electrocatalytic hydrogen evolution performance.

[0068] Figure 5 From the constant current charge-discharge cycle test of Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C@S positive electrode assembled lithium-sulfur battery releases an initial discharge capacity of 1368mAh / g at a current density of 0.2C, and the capacity attenuation of each cycle is 0.068%. While the capacity attenuation of each cycle of C@S positive electrode assembled lithium-sulfur battery is 0.15%. Moreover, from the figure, Nano-(Fe 0.30 Co 0.25 CoNi 0.25 Cu 0.10 Mo 0.10 )2P / C@S show higher coulombic efficiency, and further indicate the improvement of battery stability. These results show that Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C catalysts have high efficient and stable catalytic activity.

[0069] From the SEM spectrum of Figure 6 , it can be seen that the nano-high-entropy phosphide particles Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P anchored in the carbon matrix without adding alkaline substances in Comparative Example 1 has less carbon matrix pore structure.

[0070] From the LSV test of Figure 7 , it can be seen that the nano-high-entropy phosphide Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C catalyst shows earlier half-wave potential (E half-wave ) and greater diffusion current intensity (J D ) than pure carbon in the electrocatalytic sulfur reduction reaction, but shows poorer catalytic performance than Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C catalyst with alkaline substances.

[0071] From the HER linear sweep voltammetry (LSV) test of Figure 8 , it can be seen that the nano-high-entropy phosphide Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P / C catalyst shows better activity than pure carbon in 1M KOH, but requires a overpotential of 300mV to reach 100mA cm -2 , which is larger than the overpotential when alkaline substances are added, and the catalytic activity is poor( Figure 8 Pt / C is commercially available).

[0072] Table 1 is the analysis of the content of metal elements Fe, Co, Ni, Cu, Mo and non-metallic element P in the nano-high-entropy phosphide Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P prepared by Example 1 of the present application by using inductively coupled plasma optical emission spectrometer (ICP-OES). As can be seen from the table, the atomic percentage of Fe, Co, Ni, Cu, Mo and P is 21.0%, 18.1%, 17.1%, 8.9%, 6.8% and 28.1%, respectively.

[0073] Table 1 is the analysis of the content of metal elements Fe, Co, Ni, Cu, Mo and non-metallic element P in the nano-high-entropy phosphide Nano-(Fe 0.30 Co 0.25 Ni 0.25 Cu 0.10 Mo 0.10 )2P prepared by Example 1 of the present application by using inductively coupled plasma optical emission spectrometer (ICP-OES). As can be seen from the table, the atomic percentage of Fe, Co, Ni, Cu, Mo and P is 21.0%, 18.1%, 17.1%, 8.9%, 6.8% and 28.1%, respectively.

[0074] Element Content (at. %) Fe 21.0 Co 18.1 Ni 17.1 Cu 8.9 Mo 6.8 P 28.1

[0075] The foregoing description of specific exemplary embodiments of the application has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the application to the precise form disclosed, and various modifications and variations are possible in light of the above teachings. It is intended that the application encompass all such modifications and variations as fall within the scope of the claims and their equivalents. The exemplary embodiments were chosen and described in order to explain the principles of the application and its practical application, and to thereby enable others skilled in the art to best utilize the application and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the application be defined by the claims and their equivalents.

Claims

1. A nano-high-entropy-phosphide / carbon composite material, characterized in that: Nano-(Fe a Co b Ni c Cu d Mo e )2P / C, wherein each subscript value ranges from a is 0.25-0.3, b is 0.25, c is 0.25, d is 0.1-0.13, and e is 0.1-0.12; the nano-high-entropy phosphide / carbon composite material has high and stable catalytic performance; The preparation method of the nano high-entropy phosphide / carbon composite material comprises the following operation steps: (1) soak the phosphorus-containing resin in an acid solution to adjust the pH value of the phosphorus-containing resin to 5-7, vacuum filter, dry, and then crush; (2) The phosphorus-containing resin obtained after crushing in step (1) is added with water and stirred thoroughly to obtain a mixture. The Fe salt, Co salt, Ni salt, Cu salt and Mo salt solutions are mixed uniformly and added to the mixture, stirred, vacuum filtered and dried to obtain a precursor resin containing Fe, Co, Ni, Cu and Mo, denoted as M + resin; the concentration of the Fe salt is 0.2-0.6 mol / L; (3) grinding the M + resin obtained in step (2) with an alkaline substance + The mass ratio of the resin to the alkaline substance is 1:0.05-0.4, and the mixture is heat-treated under a protective gas. After the reaction is completed, the mixture is cooled, washed to neutral, and dried to obtain a nanometer high-entropy phosphide / carbon composite material.

2. The nano-high-entropy phosphide / carbon composite of claim 1, wherein: The phosphorus-containing resin in step (1) is LXP-P01 resin; the acid solution in step (1) is one of hydrochloric acid solution, nitric acid solution or acetic acid solution; the concentration of the acid solution is 0.5-2.5 mol / L.

3. The nanohigh-entropy phosphide / carbon composite of claim 1, wherein: After vacuum filtration in step (1), dry at 60°C until the moisture content is not more than 8%, and then crush.

4. The nano-high-entropy phosphide / carbon composite of claim 1, wherein: In step (2), 5 mL of water is added per gram of phosphorus-containing resin.

5. The nano-high-entropy phosphide / carbon composite of claim 1, wherein: In step (2), the Fe salt, Co salt, Ni salt, Cu salt and Mo salt solution are each added in an amount of 50 mL; the Fe salt is iron chloride; the Co salt is cobalt chloride, with a concentration of 0.2-0.6 mol / L; the Ni salt is nickel chloride, with a concentration of 0.2-0.6 mol / L; the Cu salt is copper chloride, with a concentration of 0.2-0.6 mol / L; and the Mo salt is molybdenum pentachloride, with a concentration of 0.2-0.6 mol / L.

6. The nano-high-entropy phosphide / carbon composite of claim 1, wherein: After vacuum filtration in step (2), completely dry at 60°C; in step (3), the drying is complete drying at 60°C.

7. The nano-high-entropy phosphide / carbon composite of claim 1, wherein: In step (2), the stirring is carried out at a temperature of 50-65°C, a stirring rate of 300 rpm, and for 3-6 h.

8. The nano-high-entropy phosphide / carbon composite of claim 1, wherein: The base substance in step (3) is one of potassium hydroxide or sodium hydroxide; the protective gas in step (3) is N2or Ar atmosphere; M + The resin addition amount is 1-3 g.

9. The nano-high-entropy phosphide / carbon composite of claim 1, wherein: The heat treatment in step (3) is: heating at a rate of 5-10°C / min to 750-1050°C, and holding for 1-3 h.

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