Method for preparing carbon fiber catalyst loaded with high-entropy amorphous alloy particles by using ultrafast heating

Abstract

The invention discloses a method for preparing a carbon fiber catalyst loaded with high-entropy amorphous alloy particles by using ultrafast heating. The method comprises the steps that soluble metal salt corresponding to the high-entropy alloy and a P-containing compound are mixed and then added into a solvent, a saturated solution is obtained, carbon fiber powder is soaked for 5 min and then dried, rapid heating is conducted at the high temperature, the catalyst is obtained, and the molar ratio of all metal elements in the high-entropy alloy to P in the P-containing compound, namely Fe: Co: Ni: Cu: Al: P is 0.04: 0.04: 0.04: 0.04: 0.04: 1. A proper amount of P is added to form an atomic radius difference with a transition metal element, and a material is generated at an ultra-fast speed, so that an amorphous high-entropy metastable state structure is formed, the obtained catalyst can be used for electrocatalytic oxygen evolution reaction and has excellent catalytic performance, the overpotential can reach 273 mV under the current density of 10 mA / cm < 2 >, and the catalytic efficiency is greatly improved.

Description

TECHNICAL FIELD

[0001] The application relates to a method for synthesizing a carbon fiber powder catalyst loaded with high-entropy amorphous alloy particles by using ultrafast heating, and belongs to the technical field of electrocatalysis. BACKGROUND

[0002] Electrocatalytic water splitting has been proven to be an economically efficient and clean energy conversion technology, and has received great attention in the past few decades. The oxygen evolution reaction (OER) is an indispensable half-reaction for the production of hydrogen energy by electrocatalytic water splitting. However, because the OER is a four-electron system with slow reaction kinetics, a large overpotential is required to achieve the desired current density. Currently, noble metal catalysts based on ruthenium and iridium are typical commercial electrocatalysts for OER. However, the high cost and scarcity of noble metal-based catalysts greatly hinder their practical application. The instability of noble metal-based catalysts also makes the material lose a certain competitive advantage. Therefore, the development of efficient, durable and low-cost electrocatalysts is crucial for reducing the overpotential and improving the overall OER performance.

[0003] High-entropy alloy (HEA) is a crystalline solid solution composed of five or more main elements at an atomic ratio or near atomic ratio (each element content is between 5-35 at.%). Due to the different effects from traditional materials, slow diffusion and cocktail effect. Slow atomic diffusion and multi-element mixing endow the intrinsic synergistic effect of tunable electronic structure. The lattice distortion effect and entropy stabilization effect can effectively improve the catalytic activity and durability of HEA in electrochemical processes. How to further research, develop and apply high-entropy alloys has attracted more and more attention. Unlike bulk high-entropy alloys, structural HEA is more attractive due to its rich catalytic active sites. However, due to the immiscibility of element combination, it is very difficult to realize single-phase multi-metallic materials. SUMMARY

[0004] The application discloses a method for synthesizing a carbon fiber catalyst loaded with high-entropy amorphous alloy particles by using ultrafast heating. The catalyst has high OER activity under alkaline conditions and is low in price.

[0005] In a first aspect, the application provides a method for synthesizing a carbon fiber catalyst loaded with high-entropy amorphous alloy particles by using ultrafast heating, comprising the following steps:

[0006] Step 1, mixing the soluble metal salt corresponding to the high-entropy alloy and the P-containing compound, and then adding a solvent to obtain a saturated solution, wherein the molar ratio of each metal element in the high-entropy alloy to P in the P-containing compound is Fe:Co: Ni:Cu:Al:P=0.04:0.04:0.04:0.04:0.04:1;

[0007] Step 2: Soak the carbon fiber powder in the saturated solution obtained in Step 1 for 5 minutes, and then dry it for 0.5-1 hour;

[0008] Step 3: Under an argon atmosphere, the powder obtained in Step 2 is heated at a high temperature of 900-1200℃ for 0.1-1s to obtain the catalyst.

[0009] Preferably, in step 1, the soluble metal salt corresponding to the high-entropy alloy is one of the chloride, nitrate, acetate, or sulfate of each metal.

[0010] Preferably, in step 1, the P-containing compound is phosphoric acid, phosphorous acid, or phosphorus oxide, etc.

[0011] Preferably, the solvent is one or more of water, ethanol, ethylene glycol, and chloroform.

[0012] Preferably, in step 1, ultrasonic vibration is used to mix the materials evenly for a period of 20 minutes or more; more preferably, the ultrasonic vibration time is 30 minutes.

[0013] Preferably, in step 2, the product is dried at 160-200℃ for 0.5-1h.

[0014] Preferably, in step 2, soaking for at least 5 minutes is required.

[0015] Preferably, in step 3, the powder from step 2 is heated at a high temperature of 900-1200℃ for 0.1-1s using a Joule heating device.

[0016] Preferably, the mass content of high-entropy alloy in the catalyst is 20-40 wt%.

[0017] In a second aspect, the present invention provides a carbon fiber catalyst loaded with high-entropy amorphous alloy particles prepared by the method described in the first aspect, wherein the active component of the catalyst is a P-doped high-entropy amorphous alloy.

[0018] In a second aspect, the present invention provides the application of the carbon fiber catalyst loaded with high-entropy amorphous alloy particles prepared by the method described in the first aspect in the electrolysis of water under alkaline conditions.

[0019] In the above applications, the catalyst loading on the working electrode is 1-2 mg / cm². 2 The electrolyte is 1.0 MkOH.

[0020] In the above applications, the alkaline condition is a pH value of 9-14.

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

[0022] (1) The carbon fiber catalyst with loaded high-entropy amorphous alloy particles described in this invention is fast, mature, simple to operate, and easy to produce on a large scale.

[0023] (2) The raw material metal salts of the catalyst described in this invention are widely available and inexpensive.

[0024] (3) The solvent used in the preparation process of the electrocatalyst described in this invention is a green or low-toxic solvent, which is low in cost and safe in operation.

[0025] (4) The catalyst product described in this invention is in powder form and can be directly used in the preparation of electrocatalytic electrodes without the need for crushing or pulverizing.

[0026] (5) The catalyst prepared by the method of the present invention has excellent performance and can further expand the application of catalysts, realize the commercial application of gold electrochemical catalysts, and has a wide application prospect. Attached Figure Description

[0027] Figure 1 The temperature curve of the Joule heating process in Example 1 shows that the heating time at 1000℃ is only about 0.15s.

[0028] Figure 2 Example 1: Carbon fiber powder supported high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 The XRD pattern of P confirms its amorphous structure.

[0029] Figure 3 Example 1: Carbon fiber powder supported high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 The SEM image of P proves that alloy particles are loaded on the carbon fiber powder.

[0030] Figure 4 Example 1: Carbon fiber powder supported high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 The TEM diffraction pattern of P confirms that it is an amorphous particle.

[0031] Figure 5 Example 1: Carbon fiber powder supported high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al0.04 The LSV results of P's OER demonstrate that its OER catalytic performance is superior to that of the commercial noble metal catalyst RuO2.

[0032] Figure 6 Example 2: Carbon fiber powder supported high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.0 4P 0.5 The XRD pattern confirms its crystal structure.

[0033] Figure 7 Example 2: Carbon fiber powder supported high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.0 4P 0.5 The LSV results of the OER demonstrate that its OER catalytic performance is inferior to that of the carbon fiber powder-supported high-entropy alloy particle catalyst Fe. 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 P. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0035] This invention utilizes a high-entropy amorphous alloy particles prepared by a high-temperature thermal shock ultrafast synthesis method and supported on carbon nanofibers as an electrochemical powder catalyst for the oxygen evolution reaction (OER) catalysis, providing a new approach for the preparation of highly catalytically active catalysts for water electrolysis.

[0036] The transition metal salts and phosphoric acid used in the following examples are commercially available. The specific preparation method is as follows:

[0037] Step 1: Prepare reactants and reagents: Prepare five transition metal salts and phosphoric acid as precursors, and prepare an appropriate amount of ethanol as solvent.

[0038] Step 2: Mixing reactants: Slowly mix appropriate amounts of transition metal salt, phosphoric acid, and ethanol solution in a container as a saturated precursor solution. The transition metal salt and phosphoric acid are mixed in a molar ratio of Fe:Co:Ni:Cu:Al:P = 0.04:0.04:0.04:0.04:0.04:1 and then ultrasonically vibrate to mix evenly.

[0039] Step 3: Loading precursor: Immerse the carbon fiber powder in the precursor solution for at least 5 minutes, and then dry it after immersion.

[0040] Step 4 Synthesis process: The precursor powder is calcined at 900-1200℃ for 0.1-1s using a Joule heating device under an argon atmosphere.

[0041] Step 5 Testing: After the reaction is complete, take out the obtained catalyst powder. Since the powder is clumped, grind it slightly and then perform ICP test and electrochemical OER test.

[0042] Example 1

[0043] Step 1: Prepare the transition metal salt and phosphoric acid in a molar ratio of Fe:Co:Ni:Cu:Al:P = 0.04:0.04:0.04:0.04:1. Specifically, take 0.27g of commercially available FeCl3·6H2O, 0.237g of CoCl2·6H2O, 0.237g of NiCl2·6H2O, 0.17g of CuCl2·2H2O, and 0.24g of AlCl3·6H2O (Ron Company, 99% purity), dissolve them in 4mL of 75% ethanol solution, and sonicate for 0.5 hours to mix thoroughly.

[0044] Step 2: Add 2 mL of H3PO4 solution (Chengdu Kelong Chemical Co., Ltd., purity 85%) to the mixed solution from Step 1, and sonicate for 0.5 hours to mix thoroughly.

[0045] Step 3: Soak an appropriate amount of carbon fiber (Zhongke Leiming Company, fiber diameter about 100nm) in the solution from Step 2 (complete immersion is sufficient) for 5 minutes, and then dry it at 200℃ until fully dry to obtain the precursor powder of the catalyst.

[0046] Step 4: The powder from Step 3 was calcined at 1000℃ under an argon atmosphere for 0.15s using a Joule-heated ultrafast synthesis apparatus (Zhongke Jingyan Company) to obtain carbon fiber powder-supported high-entropy alloy particle catalyst Fe. 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 P.

[0047] Step 5: Grind the catalyst powder obtained in Step 4. Take 10 mg of the ground powder, add 1 mL of 75% ethanol and 3-4 drops of 75% naphthol solution to prepare the ink solution required for the electrochemical catalytic reaction. Drop the solution onto a glassy carbon electrode or carbon paper as the working electrode for OER electrocatalysis. (The loading of the metal catalyst on the working electrode is 2 mg / cm³.) 2 about.)

[0048] Example 2

[0049] The transition metal salt and phosphoric acid were mixed in a molar ratio of Fe:Co:Ni:Cu:Al:P = 0.04:0.04:0.04:0.04:0.5, with other processes and conditions the same as in Example 1, to obtain a carbon fiber powder-supported high-entropy alloy particle catalyst Fe. 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 P 0.5 .

[0050] Characterization experiments and results of the samples obtained in Example 1:

[0051] (1) Infrared thermometry is performed on the Joule heating process, such as... Figure 1 It can be seen that the synthesis process was heated at 1000℃ for about 0.15 seconds.

[0052] (2) The obtained carbon fiber powder was loaded with high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 P performs XRD testing, such as Figure 2 As can be seen, this material has no crystal diffraction peaks, has poor crystallinity, and belongs to an amorphous structure.

[0053] (3) The obtained carbon fiber powder was loaded with high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 P performs SEM testing, such as Figure 3 Alloy particles can be seen loaded onto the carbon fiber powder.

[0054] (4) The obtained carbon fiber powder was loaded with high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 P undergoes TEM testing, such as Figure 4 The diffraction pattern shows that it is an amorphous particle.

[0055] (5) The obtained carbon fiber powder was loaded with high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 P performs LSV testing on OER, such as Figure 5 It can be seen that its OER catalytic performance is superior to that of commercial noble metal catalyst RuO2 (10 mA / cm).2 The overpotential at the current density is 273 mV.

[0056] (6) The obtained carbon fiber powder was used to support high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 ICP testing was performed on P. Table 1 shows the ICP results of the carbon fiber powder-supported high-entropy alloy particle catalyst in Example 1. The molar ratio of Fe:Co:Ni:Cu:Al:P is 5:5:5:5:3:77.

[0057] Table 1

[0058]

[0059] Characterization experiments and results of the samples obtained in Example 2:

[0060] (1) The obtained carbon fiber powder was loaded with high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 P 0.5 Perform XRD testing, such as Figure 6 The material exhibits crystal diffraction peaks, indicating a crystalline structure, which proves that differences in elemental proportions affect the material's crystallinity.

[0061] (2) The obtained carbon fiber powder was loaded with high-entropy alloy particle catalyst Fe 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 P 0.5 Perform LSV testing on OER, such as Figure 7 Its OER catalytic performance (10 mA / cm) can be observed. 2 The overpotential at the current density is 282.8 mV, which is lower than that of the Fe high-entropy alloy particle catalyst supported by carbon fiber powder. 0.04 Co 0.04 Ni 0.04 Cu 0.04 Al 0.04 P(10mA / cm 2 The overpotential at the current density is only 273mV.

Claims

1. A method for preparing carbon fiber catalysts supported on high-entropy amorphous alloy particles by ultrafast heating, characterized in that, Includes the following steps: Step 1: Mix the soluble metal salt corresponding to the high entropy alloy and the P-containing compound, then add a solvent to obtain a saturated solution. The molar ratio of each metal element in the high entropy alloy to P in the P-containing compound is Fe:Co:Ni:Cu:Al:P = 0.04:0.04:0.04:0.04:0.04:

1. Step 2: Soak the carbon fiber powder in the saturated solution obtained in Step 1 for 5 minutes, and then dry it. Step 3: Under an argon atmosphere, the powder from Step 2 is heated at a high temperature of 900-1200℃ for 0.1-1s to obtain the catalyst.

2. The method as described in claim 1, characterized in that, The soluble metal salts corresponding to high-entropy alloys are one of the chlorides, nitrates, acetates, or sulfates of each metal.

3. The method as described in claim 1, characterized in that, P-containing compounds include phosphoric acid, phosphorous acid, or phosphorus oxide.

4. The method as described in claim 1, characterized in that, The solvent is one or more of water, ethanol, ethylene glycol, and chloroform.

5. The method as described in claim 1, characterized in that, In step 2, dry at 160-200℃ for 0.5-1h.

6. The method as described in claim 1, characterized in that, The mass content of high-entropy alloy in the catalyst is 20-40 wt%.

7. The method as described in claim 1, characterized in that, In step 3, a Joule heating device is used to heat the product at a high temperature of 900-1200℃ for 0.1-1 seconds.

8. The carbon fiber catalyst supported on high-entropy amorphous alloy particles prepared by the method according to any one of claims 1-7, characterized in that, The active component of the catalyst is a P-doped amorphous high-entropy amorphous alloy.

9. The application of the carbon fiber catalyst loaded with high-entropy amorphous alloy particles prepared by the method according to any one of claims 1-7 in the electrolysis of water under alkaline conditions.

10. The application as described in claim 9, characterized in that, The catalyst loading on the working electrode is 1-2 mg / cm². 2 .

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