A method for preparing carbon-coated high-entropy alloy by photoreduction

Abstract

A method for preparing a carbon-coated high-entropy alloy by photoreduction includes the following steps: (a) dissolving carbon quantum dots and a transition metal salt in anhydrous ethanol to prepare solution A; (b) dispersing a conductive carbon material into solution A from step (a) to prepare dispersion B; (c) irradiating dispersion B obtained from step (b) under a light source for 0.5 to 6 hours to obtain dispersion C; and (d) centrifuging dispersion C obtained from step (c) to obtain a solid, which is then washed to obtain a carbon-coated high-entropy alloy. This method can produce amorphous carbon-coated high-entropy alloy nanoparticles or atomic clusters, significantly improving the catalytic activity and durability of precious metals. The product is particularly suitable for use in fields such as water splitting to produce hydrogen and fuel cells. It can inhibit the reverse water splitting reaction on the precious metal surface and exhibits high catalytic activity and good cyclic stability.

Description

Technical Field

[0001] The present invention relates to the field of electrochemistry, and in particular to a carbon-coated high-entropy alloy and a photoreduction preparation method thereof. Background Art

[0002] Currently, high-performance catalysts are key materials for water splitting, hydrogen production, fuel cells, pollutant purification, and organic reactions. However, the high use of precious metals can lead to oxidation, aggregation, and the induction of reverse or side reactions of the target reaction during catalytic reactions, resulting in high catalyst costs and limiting their performance. CN118086948A discloses a porous high-entropy alloy catalytic electrode based on a B2-BCC structure, its preparation method, and its application in acidic oxygen evolution. The catalytic electrode is designed to consist of a high-entropy alloy formed by a B2 structure-forming component A, a refractory metal passivating component M, and a precious metal active component Q. The high-entropy alloy is AxMyQz; A is selected from at least two of Ni, Ti, Al, and Fe; M is selected from at least one of Ta, Nb, Hf, W, and Mo; and Q is selected from at least two of Ir, Os, Ru, and Pt. Under conditions where the B2 phase composed of Ni and Ti is selectively corroded, a three-dimensional bicontinuous through-pore structure with pore sizes of 0.5-2 μm is formed on the surface of the catalytic electrode. CN118028930A discloses a method for preparing a high-entropy alloy coating catalyst using pulse electrodeposition. By controlling parameters such as the pulse electrodeposition waveform, frequency, on-off ratio, and average current density, concentration polarization at the cathode interface is reduced or eliminated. Simultaneously, multi-element co-deposition is achieved by coupling pulse electrodeposition technology with a multi-component complexing agent. CN118002144A discloses a method for preparing a copper-based high-entropy alloy Fenton-like catalyst based on a controllable electrodeposition method. A pure copper electrode is selected as the cathode, and a graphite electrode is selected as the anode. An electrodeposition device is constructed using the cathode and anode, and copper-based high-entropy micro-nano alloy powder is deposited on the cathode. CN117798357A discloses a method for preparing palladium-ruthenium-based high-entropy alloy nanosheets by thermal reduction of a mixture of a palladium source, a ruthenium source, an auxiliary metal precursor (the auxiliary metal precursor contains at least one carbonyl salt), a reducing agent, and cyclohexane-ethanol. CN117965919A discloses a method for preparing a carbon-supported platinum group metal-based high-entropy alloy using a 200°C hydrothermal method. CN117737772A discloses a method for preparing a stainless steel electrode mesh for electrolytic hydrogen production based on etching activation, vapor deposition and alloy forming. CN118073586A discloses a method and application for preparing a high entropy alloy by impregnating a metal organic framework material with a loaded transition metal after pyrolysis. CN117936821A discloses a tetragonal platinum iron nickel copper based high entropy alloy catalyst and its gram-level preparation method and application, wherein the preparation method is liquid-phase ultrasonic dispersion of a metal precursor and a carbon carrier + grinding + calcination. CN117966191A discloses a method for depositing a high entropy alloy film on a conductive substrate material by a pulsed laser deposition method. CN117702175A discloses a method for preparing a nanoporous high entropy alloy / hydroxy oxide electrocatalyst by a high entropy alloy mesh, dealloying treatment and surface activation treatment.CN117983214A discloses a method of mixing a soluble metal salt solution with a reducing agent and a flocculant, heating and melting the mixture to produce a preheated reduced phase, then injecting a metal precursor solution into the preheated reduced phase to produce crude catalyst particles, and post-treating the crude catalyst particles to produce high-entropy alloy particles. CN117894937A discloses a method for preparing a high-entropy alloy-loaded graphene oxide composite material by a hydrothermal method and calcination in a reducing atmosphere, and its application. CN117718485A prepares nitrogen-doped carbon-coated copper-nickel-iron-cobalt-chromium-titanium high-entropy alloy nanospheres by ball milling and DC arc discharge reaction of a mixed powder of six metals in equal molar ratios. CN117680690A prepares a nanoscale high-entropy alloy electrocatalyst by loading the nanoscale high-entropy alloy obtained by heat-treating a precursor onto a conductive carrier XC-72. CN117463362A prepares a carbon-based high-entropy alloy catalyst by loading high-entropy alloy nanoparticles on the surface of a carbon-based material through a one-pot reduction method combined with high-temperature annealing.

[0003] The challenges faced by existing methods in preparing high-entropy alloy catalysts include complex preparation processes, high costs, insufficient catalytic performance, and stability and durability in electrochemical applications.

[0004] It should be noted that the information disclosed in the above background technology section is only used to understand the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0005] The main purpose of the present invention is to solve the problems existing in the above-mentioned background technology and provide a method for preparing carbon-coated high entropy alloy by photoreduction method.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a carbon-coated high-entropy alloy by a photoreduction method comprises the following steps:

[0008] (a) dissolving carbon quantum dots and transition metal salt in anhydrous ethanol to prepare solution A;

[0009] (b) dispersing the conductive carbon material into the solution A of step (a) to prepare a dispersion B;

[0010] (c) irradiating the dispersion B obtained in step (b) under a light source for 0.5 to 6 hours to obtain a dispersion C;

[0011] (d) centrifuging the dispersion C obtained in step (c) to obtain a solid, and washing the solid to obtain a carbon-coated high-entropy alloy.

[0012] Further:

[0013] In step (a), the weight ratio of carbon quantum dots: transition metal salt calculated as metal: ethanol is 1:0.01 to 1:4 to 50.

[0014] In step (a), the transition metal salt is selected from chlorides, nitrates, sulfates, acetates and mixtures thereof, preferably chlorides.

[0015] In step (a), the transition metal is selected from Fe, Co, Ni, Cu, Ag, Au, Pt, Rh, Pd, Ir, Ru, and Os.

[0016] In step (b), the conductive carbon material is selected from graphene, carbon nanotubes, carbon black, Ketjen black, and acetylene black.

[0017] In step (b), the amount of the conductive carbon material used is 1 to 20 times the weight of the carbon quantum dots.

[0018] In step (c), the light source is selected from light with a wavelength of 200nm to 2000n and a power of 10 to 2000W.

[0019] The light source is sunlight or a xenon lamp simulating sunlight.

[0020] A carbon-coated high-entropy alloy is prepared by a photoreduction method. The alloy is prepared by the method for preparing a carbon-coated high-entropy alloy by a photoreduction method.

[0021] The present invention has the following beneficial effects:

[0022] The present invention provides a method for preparing a carbon-coated high-entropy alloy by a photoreduction method, wherein carbon quantum dots are used as a photosensitizer, and conductive carbon is used as a charge transfer aid and a carrier of a transition metal. During the photoreduction process, the carbon dots polymerize on the surface of the high-entropy alloy, which can simultaneously reduce the particle size of the high-entropy alloy and protect the high-entropy alloy from oxidation. In the catalytic reaction, the reverse reaction of water decomposition can be inhibited, thereby improving the stability of the catalyst in catalytic reactions such as water decomposition reactions, and has significant practical value.

[0023] The preparation method of the present invention can achieve amorphous carbon-coated high-entropy alloy nanoparticles or atomic clusters, significantly improving the catalytic activity and durability of precious metals. The product is particularly suitable for fields such as water splitting hydrogen production and fuel cells. It can inhibit the reverse water splitting reaction on the precious metal surface and has high catalytic activity and good cyclic stability. The prepared product can be applied to water splitting hydrogen production, fuel cells, and other applications involving precious metal catalysis.

[0024] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 TEM+EDS mapping diagram of Example 1 of the present invention;

[0026] Figure 2 TEM+EDS mapping diagram of Example 2 of the present invention;

[0027] Figure 3 HER performance diagram in 0.5M H2SO4 electrolyte of Example 1 of the present invention;

[0028] Figure 4 This is a diagram of the OER performance in 0.5M H2SO4 electrolyte of Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present invention and its application.

[0030] The present invention provides a method for preparing a carbon-coated high-entropy alloy by a photoreduction method, comprising the following steps:

[0031] (a) dissolving carbon quantum dots and transition metal salt in anhydrous ethanol to prepare solution A;

[0032] (b) dispersing the conductive carbon material into the solution A of step (a) to prepare a dispersion B;

[0033] (c) irradiating the dispersion B obtained in step (b) under a light source for 0.5 to 6 hours to obtain a dispersion C;

[0034] (d) centrifuging the dispersion C obtained in step (c) to obtain a solid, and washing the solid to obtain a carbon-coated high-entropy alloy.

[0035] In some embodiments, in step (a), the weight ratio of carbon quantum dots: transition metal salt calculated as metal: ethanol is 1:0.01 to 1:4-50.

[0036] In some embodiments, in step (a), the transition metal salt is selected from chlorides, nitrates, sulfates, acetates, and mixtures thereof, preferably chlorides.

[0037] In some embodiments, in step (a), the transition metal is selected from Fe, Co, Ni, Cu, Ag, Au, Pt, Rh, Pd, Ir, Ru, and Os.

[0038] In some embodiments, in step (b), the conductive carbon material is selected from graphene, carbon nanotubes, carbon black, Ketjen black, and acetylene black.

[0039] In some embodiments, in step (b), the amount of the conductive carbon material used is 1 to 20 times the weight of the carbon quantum dots.

[0040] In some embodiments, in step (c), the light source is selected from light with a wavelength of 200nm to 2000n and a power of 10 to 2000W.

[0041] In some embodiments, the light source is sunlight or a xenon lamp simulating sunlight.

[0042] An embodiment of the present invention further provides a carbon-coated high-entropy alloy prepared by a photoreduction method, which is prepared by the method for preparing a carbon-coated high-entropy alloy by a photoreduction method.

[0043] The present invention prepares carbon-coated high-entropy alloys by adopting a photoreduction method, cleverly utilizing carbon quantum dots as photosensitizers and conductive carbon as a charge transfer aid and carrier of transition metals, thereby achieving effective polymerization of carbon dots on the surface of the high-entropy alloy during the photoreduction process. This innovative method not only reduces the particle size of the high-entropy alloy, but also provides antioxidant protection for the high-entropy alloy, thereby effectively inhibiting the reverse reaction of water decomposition in the catalytic reaction. The catalyst thus prepared has demonstrated excellent catalytic activity and cyclic stability in applications such as water decomposition to produce hydrogen and fuel cells, significantly improving the efficiency and durability of the precious metals, ensuring the high performance and long-term effectiveness of the catalyst, and demonstrating the significant practical value and broad application prospects of the present invention in the field of precious metal catalysis.

[0044] Specific embodiments of the present invention are further described below.

[0045] Example 1

[0046] 50 mg of carbon dots were dissolved in 5 ml of anhydrous ethanol, and then chloroauric acid, platinum chloride, palladium chloride, nickel chloride, cobalt chloride, ruthenium chloride, yttrium chloride, and rhodium chloride were uniformly mixed with the carbon dot ethanol solution in a molar ratio of 1:1:1:1:1:1:1:1 (the total weight of precious metals was 10 wt.% of the weight of carbon dots). Then 0.5 g of CNT was added and stirred for 30 minutes. Then the mixture was transferred to a xenon lamp light source for irradiation for 30 minutes. The obtained solid was then washed and dried to obtain an eight-element catalyst (catalyst 1).

[0047] Example 2

[0048] 50 mg of carbon dots were dissolved in 5 ml of anhydrous ethanol, and then chloroauric acid, platinum chloride, nickel chloride, cobalt chloride, ruthenium chloride, and yttrium chloride were uniformly mixed with the carbon dot ethanol solution in a molar ratio of 1:1:1:1:1:1 (the total weight of precious metals was 10 wt.% of the carbon dot weight). Then 0.5 g of CNT was added and stirred for 30 minutes. Then, the mixture was transferred to a xenon lamp light source for irradiation for 30 minutes. The obtained solid was then washed and dried to obtain a six-way catalyst (catalyst 2).

[0049] Example 3

[0050] 50 mg of carbon dots were dissolved in 5 ml of anhydrous ethanol, and then chloroauric acid, platinum chloride, and ruthenium chloride were uniformly mixed with the carbon dot ethanol solution in a molar ratio of 1:1:1 (the total weight of the precious metals was 10 wt.% of the carbon dot weight). Then 0.5 g of CNT was added and stirred for 30 minutes. Then, the mixture was transferred to a xenon lamp light source for 30 minutes. The obtained solid was then washed and dried to obtain a ternary catalyst (catalyst 3).

[0051] Example 4

[0052] The steps were the same as those in Example 1, except that 0.5 g of CNT was replaced with 0.5 g of graphene.

[0053] Example 5

[0054] The steps were the same as in Example 1, except that 0.5 g of CNT was replaced with 0.5 g of carbon black.

[0055] Application Examples

[0056] Electrode preparation: The detailed preparation process of the working electrode is as follows: 5 mg of catalyst powder was dispersed in a mixed solution of 970 μL of ethanol and 30 μL of 5 wt.% Nafion solution, and ultrasonicated for 30 min. Then, 200 μL of the evenly dispersed suspension was dropwise dropped onto a 1×1.5 cm2 carbon cloth, with the catalyst coverage area maintained at 1 cm2. The mixture was fully dried in air.

[0057] Figure 1 This is the TEM+EDS mapping diagram of Example 1 of the present invention, showing the high entropy cluster catalyst of carbon-coated Ni-Co-Ru-Rh-Pd-Ir-Pt / CNT seven-membered single atom. Figure 1 It can be seen that all metals are evenly dispersed without obvious agglomeration, indicating that a homogeneous high entropy alloy has been formed; Figure 2 This is the TEM+EDS mapping diagram of Example 2 of the present invention, showing the preparation of carbon-coated Ni-Co-Ru-Rh-Pd-Ir-Pt / CNT high entropy nanocatalyst based on the photoreduction method of carbon quantum dots. Figure 2 It can be seen that as the components decrease, all metals are evenly dispersed without obvious agglomeration, indicating that the formation of homogeneous high-entropy alloys mainly depends on the rapid and uniform photochemical deposition on the carbon surface, which has nothing to do with the amount of components. Figure 3 is the HER performance diagram of Example 1 of the present invention, Figure 3 As can be seen in the figure, HER is carried out in 0.5M H2SO4 electrolyte, reaching 10mA cm -2 The current density only requires an overpotential of 29 mV, and after 10,000 cycles, the performance is still better than that of commercial Pt / C catalysts. Figure 4 is the OER performance diagram of Example 1 of the present invention, Figure 4As can be seen in the figure, the OER in 0.5 M H2SO4 electrolyte reaches 10 mA cm -2 The current density only requires an overpotential of 1.45mV, and after 20,000 cycles, there is no obvious performance degradation.

[0058] The above description further details the present invention in conjunction with specific / preferred embodiments, and the specific implementation of the present invention should not be construed as being limited to these descriptions. Persons skilled in the art will appreciate that, without departing from the spirit of the present invention, they may make various substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered to fall within the scope of protection of the present invention. Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples" indicates that the specific features, structures, materials, or characteristics described in conjunction with such embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Persons skilled in the art may combine and assemble the different embodiments or examples described in this specification, as well as features of different embodiments or examples, without conflicting opinions. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the scope of protection of the patent application.

Claims

1. A method for preparing a carbon-coated high entropy alloy by a photoreduction method, characterized in that: The steps include: (a) dissolving carbon quantum dots and a transition metal salt in anhydrous ethanol to prepare a solution A; the transition metal is selected from Fe, Co, Ni, Cu, Ag, Au, Pt, Rh, Pd, Ir, Ru, and Os; (b) dispersing the conductive carbon material into the solution A of step (a) to prepare a dispersion B; (c) irradiating the dispersion B obtained in step (b) under a light source for 0.5 to 6 hours to obtain a dispersion C; the light source is selected from light with a wavelength of 200 nm to 2000 nm and a power of 10 to 2000 W; (d) Centrifuging the dispersion C obtained in step (c) to obtain a solid, and washing the solid to obtain a carbon-coated high-entropy alloy.

2. The method for preparing a carbon-coated high entropy alloy by photoreduction according to claim 1, wherein: In step (a), the weight ratio of carbon quantum dots: transition metal salt calculated as metal: ethanol is 1:0.01-1:4-50.

3. The method for preparing a carbon-coated high entropy alloy by photoreduction according to claim 1 or 2, wherein: In step (a), the transition metal salt is selected from chlorides, nitrates, sulfates, acetates and mixtures thereof.

4. The method for preparing a carbon-coated high entropy alloy by photoreduction according to claim 3, wherein: In step (a), the transition metal salt is a chloride salt.

5. The method for preparing a carbon-coated high entropy alloy by photoreduction according to any one of claims 1 to 2, wherein: In step (b), the conductive carbon material is selected from graphene, carbon nanotubes, carbon black, Ketjen black, and acetylene black.

6. The method for preparing a carbon-coated high entropy alloy by photoreduction according to any one of claims 1 to 2, wherein: In step (b), the amount of the conductive carbon material is 1 to 20 times the weight of the carbon quantum dots.

7. The method for preparing a carbon-coated high entropy alloy by photoreduction according to any one of claims 1 to 2, characterized in that: The light source is sunlight or a xenon lamp simulating sunlight.

8. A carbon-coated high entropy alloy prepared by a photoreduction method, characterized in that: The carbon-coated high-entropy alloy is prepared by the method for preparing a carbon-coated high-entropy alloy by photoreduction as described in any one of claims 1 to 7.

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