Hydrotalcite-like two-dimensional supported alloy catalyst and its preparation method and application

Abstract

The present invention discloses a two-dimensional hydrotalcite-like supported alloy catalyst, its preparation method, and application. The preparation method comprises: subjecting a rare earth hydrotalcite precursor solution comprising a first rare earth metal salt, a second rare earth metal salt, an intercalating agent, and a solvent to a hydrothermal reaction to produce a rare earth hydrotalcite; or subjecting a first mixed reaction system comprising a first rare earth metal salt, a second rare earth metal salt, and a solvent to a hydrothermal reaction, then adding an intercalating agent to the resulting hydrothermal reaction product and subjecting it to a microwave intercalation reaction to produce a rare earth hydrotalcite; immersing the rare earth hydrotalcite in a solution comprising a platinum source to react and form a rare earth hydrotalcite / platinum hydroxide complex; and, subjecting the rare earth hydrotalcite / platinum hydroxide complex to a high-temperature annealing treatment in a reducing atmosphere to produce a two-dimensional hydrotalcite-like supported alloy catalyst. The two-dimensional hydrotalcite-like supported alloy catalyst prepared by the present invention has a low Pt content and high mass and charge transfer efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of energy and clean technology, and specifically relates to a hydrotalcite-like two-dimensional supported alloy catalyst and a preparation method and application thereof. Background Art

[0002] Strong reliance on fossil fuels makes national economies highly vulnerable to price increases, while excessive fossil fuel use exacerbates air pollution and global warming. Therefore, the development of clean, renewable alternative energy sources is urgently needed. Among various alternative energy strategies, building an energy infrastructure with hydrogen as the primary carrier, connecting vast amounts of energy to diverse end uses, can achieve a secure and clean energy future. To this end, efficient hydrogen storage and production are key elements of a hydrogen economy. Unlike oil and natural gas, hydrogen is not energy itself but rather a carrier for storing and transporting energy. Hydrogen does not occur naturally on Earth, so it must be produced before it can be used. Currently, there are three main industrial hydrogen production pathways: methane steam reforming, coal gasification, and water electrolysis. Methane steam reforming and coal gasification produce over 95% of total hydrogen, while water electrolysis produces only 4%. Clearly, current primary hydrogen production still relies heavily on fossil fuels. However, fossil fuel-based hydrogen production technologies cannot truly address pollution and CO2 emissions. Of the three main hydrogen production pathways, water electrolysis offers the promise of sustainable hydrogen production because its starting material is water—an abundant and renewable source of hydrogen—and the production reaction is driven by electricity generated from solar, wind, or other renewable sources. Hydrogen's potential use in transportation as a replacement for petroleum-based fuels is attracting increasing attention. Hydrogen-powered vehicles offer comparable performance to gasoline-powered vehicles, but without the polluting emissions. Many of the world's major automakers, including Ford, Toyota, BMW, and Hyundai, are committed to bringing fuel cell electric vehicles into a clear and realistic future. If hydrogen-powered vehicles become commonplace, our demand for hydrogen will increase dramatically. This will necessitate large-scale, more environmentally friendly production of hydrogen.

[0003] Water electrolysis may be a technology that can meet our requirements. However, the high cost of this technology limits its widespread practical application. Although water electrolysis has a long history, continuous technological improvements and material innovations are still needed to significantly reduce the cost of this process. Platinum metal is currently widely used as an electrocatalyst for hydrogen evolution through the positive electrode (HER) of water splitting. However, the reserves of platinum in the earth are scarce and the cost is high. Therefore, reducing the amount of platinum and developing highly active platinum-based hydrogen evolution electrocatalysts is urgent.

[0004] Fully exposing the catalyst's active sites and optimizing their structure can significantly enhance the catalytic activity of HER electrocatalysts. Alloying Pt with rare earth metals can manipulate the structure of the catalyst's active sites, enhancing the catalyst's intrinsic activity while reducing the amount of precious metal Pt required. Uniformly dispersing catalyst particles on an anisotropic support fully exposes the catalyst's active sites, improving mass and charge transfer efficiency and inhibiting particle migration, aggregation, and shedding. This not only enhances catalyst activity but also improves its stability. However, the preparation of efficient, stable, and highly efficient Pt-based alloy catalysts remains a bottleneck in development.

[0005] Currently, the stability of Pt / C catalysts is poor. Pt will migrate, aggregate, and eventually fall off on the surface of the carbon support, affecting the catalytic activity. In Pt / C catalysts, both the catalyst and the support are spherical, with low mass transfer and charge transfer efficiency and low Pt atomic utilization. Chen and his colleagues uniformly loaded Pt nanoparticles on N-doped hollow porous carbon polyhedrons to form a catalyst Pt@NHPCP, which showed HER performance superior to that of commercial Pt / C catalysts. (Nano Energy. 2017, 40, 88-94. Nitrogen-doped hollow porous carbon polyhedrons embedded with highly dispersed Ptnanoparticles as a highly efficient and stable hydrogen evolution electrocatalyst.) Xiong et al. prepared a Pd@Pt core-shell structure electrocatalyst with an ultrathin Pt shell on graphene, and the current density reached 10 mA cm at an overpotential of about 15 mV. -2(Angew.Chem.Int.Ed.,2014,53:12120-12124.Surface Polarization Matters:Enhancing the Hydrogen-EvolutionReaction by Shrinking Pt Shells in Pt-Pd-Graphene Stack Structures.)。In addition, many researchers are committed to studying non-precious metal and non-metal HER electrocatalysts, such as urchin-like elemental Ni nanoparticles (Electrochimal Acta.2017, 227, 382-390, Catalytic Activity of Urchin-like NiNanoparticles Prepared by Solvothermal Method for Hydrogen Evolution Reactionin Alkaline Solution.), Co nanoparticles encapsulated in N-doped carbon nanofibers (J.Electrochem.Soc.2018, 165, J3271-J3275, Co Nanoparticles Encapsulated inPorous N-Doped Carbon Nanofibers as an Efficient Electrocatalyst for Hydrogen Evolution Reaction.), MoNi4 / MoO2@Ni (Nature Communication.2017, 8, 15437, Efficient Hydrogen Production on MoNi4 Electrocatalysts with Fast Water Dissociation Kinetics.), CuCo@NC (Advance Energy Materials.2017, 7, 1700193, Co-Embedded N-Enriched Mesoporous Carbon for Efficient Oxygen Reduction and Hydrogen Evolution Reactions.), Fe-Co-Ni ternary alloy (ACS Catalysis.2017, 7, 469-479, Tuning Electronic Structures of Nonprecious Ternary Alloys Encapsulated in Graphene Layers for Optimizing Overall Water Splitting Activity.), etc., but the catalytic activity and stability of such catalysts need to be further improved. Summary of the Invention

[0006] The main purpose of the present invention is to provide a hydrotalcite-like two-dimensional supported alloy catalyst and its preparation method and application, so as to overcome the shortcomings of the prior art.

[0007] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0008] An embodiment of the present invention provides a method for preparing a hydrotalcite-like two-dimensional supported alloy catalyst, which comprises:

[0009] A rare earth hydrotalcite precursor solution comprising a first rare earth metal salt, a second rare earth metal salt, an intercalating agent, and a solvent is subjected to a hydrothermal reaction to produce the rare earth hydrotalcite; or a first mixed reaction system comprising the first rare earth metal salt, the second rare earth metal salt, and a solvent is subjected to a hydrothermal reaction, and then an intercalating agent is added to the obtained hydrothermal reaction product and subjected to a microwave intercalation reaction to produce the rare earth hydrotalcite;

[0010] immersing the rare earth hydrotalcite in a solution containing a platinum source to react and form a rare earth hydrotalcite / platinum hydroxide complex;

[0011] Furthermore, the rare earth hydrotalcite / platinum hydroxide composite is subjected to high-temperature annealing treatment in a reducing atmosphere to obtain a hydrotalcite-like two-dimensional supported alloy catalyst.

[0012] Furthermore, the first rare earth metal salt and the second rare earth metal salt are independently selected from any one or a combination of two or more of scandium salts, yttrium salts, and lanthanide metal salts, but are not limited thereto.

[0013] Furthermore, the first rare earth metal salt and the second rare earth metal salt are two different rare earth metal salts.

[0014] The embodiment of the present invention further provides a hydrotalcite-like two-dimensional supported alloy catalyst prepared by the above method, wherein the loading amount of platinum element in the alloy catalyst is 5 to 60 wt%.

[0015] The embodiments of the present invention also provide use of the aforementioned hydrotalcite-like two-dimensionally supported alloy catalyst in the field of water electrolysis.

[0016] An embodiment of the present invention further provides a hydrogen evolution electrocatalyst, which comprises the aforementioned hydrotalcite-like two-dimensional supported alloy catalyst.

[0017] An embodiment of the present invention further provides a hydrogen evolution electrode, which comprises the aforementioned hydrotalcite-like two-dimensional supported alloy catalyst or hydrogen evolution electrocatalyst.

[0018] An embodiment of the present invention further provides a method for hydrogen evolution by electrolysis of water, comprising: in a reaction of preparing hydrogen by electrolysis of water, using the aforementioned hydrotalcite-like two-dimensional supported alloy catalyst or hydrogen evolution electrocatalyst as a hydrogen evolution electrocatalyst in the reaction.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) In the two-dimensional hydrotalcite-like supported alloy catalyst prepared by the present invention, the Pt alloy is uniformly loaded on the two-dimensional hydrotalcite-like substrate, and the layered structure of the hydrotalcite-like is retained. The prepared Pt alloy is uniformly loaded on the surface of the layered hydrotalcite-like structure. The Pt alloy is not easy to migrate and aggregate, which greatly increases the active area of ​​the catalyst, greatly improves the efficiency of mass transfer and charge transfer in the electrocatalytic process, and enhances the kinetic performance of the reaction;

[0021] (2) The Pt 4+ The redox reaction between Pt and rare earth ions anchors Pt at a specific position, and then annealing in a reducing atmosphere yields an alloy.

[0022] (3) There are many types of rare earth hydrotalcites used in the two-dimensionally supported hydrotalcite-like alloy catalyst prepared by the present invention. Different Pt alloys can be prepared by selecting different hydrotalcite-like structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 Schematic diagram of the preparation process of a hydrotalcite-like two-dimensionally supported alloy catalyst in a typical embodiment of the present invention;

[0025] Figure 2 is the X-ray diffraction pattern of the rare earth hydrotalcite and Y(Eu)-Pt alloy catalyst prepared in Example 1;

[0026] Figure 3a-Figure 3b They are scanning electron microscope images of the rare earth hydrotalcite before and after intercalation in Example 1 of the present invention;

[0027] Figure 4 is a transmission electron micrograph of the Y(Eu)-Pt alloy catalyst prepared in Example 1;

[0028] Figure 5 1 is the LSV curve of the hydrotalcite-like two-dimensional supported alloy catalyst prepared in Example 1 of the present invention and the commercial Pt / C catalyst;

[0029] Figure 6 These are the linear scan curves of the Y(Eu)-Pt alloy catalyst in Example 1 of the present invention and the commercial Pt / C catalyst before and after the accelerated life test (the test method is cyclic voltammetry test). DETAILED DESCRIPTION

[0030] In view of the shortcomings of the prior art, the inventors of this case, after long-term research and extensive practice, have proposed the technical solution of the present invention. The technical solution of the present invention will be clearly and completely described below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making any creative effort shall fall within the scope of protection of the present invention.

[0031] First, it should be noted that the definitions of the terms used in this specification are known to those skilled in the art. For example, some of the terms are defined as follows:

[0032] 1. Hydrogen evolution electrocatalyst (HER): A substance that promotes the rate of hydrogen ion reduction reaction under electrochemical conditions.

[0033] 2. Hydrotalcite-like (LDH): a series of supramolecular materials assembled by intercalation of layered double hydroxides.

[0034] One aspect of an embodiment of the present invention provides a method for preparing a hydrotalcite-like two-dimensional supported alloy catalyst, comprising:

[0035] A rare earth hydrotalcite precursor solution comprising a first rare earth metal salt, a second rare earth metal salt, an intercalating agent, and a solvent is subjected to a hydrothermal reaction to produce the rare earth hydrotalcite; or a first mixed reaction system comprising the first rare earth metal salt, the second rare earth metal salt, and a solvent is subjected to a hydrothermal reaction, and then an intercalating agent is added to the obtained hydrothermal reaction product and subjected to a microwave intercalation reaction to produce the rare earth hydrotalcite;

[0036] immersing the rare earth hydrotalcite in a solution containing a platinum source to react and form a rare earth hydrotalcite / platinum hydroxide complex;

[0037] Furthermore, the rare earth hydrotalcite / platinum hydroxide composite is subjected to high temperature annealing treatment in a reducing atmosphere to obtain a hydrotalcite-like two-dimensional supported alloy catalyst (referred to as a two-dimensional supported Pt alloy catalyst).

[0038] In some more specific embodiments, the first rare earth metal salt and the second rare earth metal salt are independently selected from any one or a combination of two or more of scandium (Sc) salts, yttrium (Y) salts, and lanthanide metal salts, and are not limited thereto.

[0039] Furthermore, the lanthanide metal salt includes any one or a combination of two or more of lanthanum (La) salts, cerium (Ce) salts, praseodymium (Pr) salts, neodymium (Nd) salts, promethium (Pm) salts, samarium (Sm) salts, europium (Eu) salts, gadolinium (Gd) salts, terbium (Tb) salts, dysprosium (Dy) salts, holmium (Ho) salts, erbium (Er) salts, thulium (Tm) salts, ytterbium (Yb) salts, and lutetium (Lu) salts, and is not limited thereto.

[0040] Furthermore, the first rare earth metal salt and the second rare earth metal salt are two different rare earth metal salts.

[0041] Furthermore, the intercalant includes any one of benzoic acid, sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate, or a combination of two or more thereof, but is not limited thereto.

[0042] In some more specific embodiments, the preparation method specifically includes:

[0043] Dissolving a first rare earth metal salt and a second rare earth metal salt in a solvent to form a rare earth metal salt solution, adjusting the pH value of the obtained rare earth metal salt solution to 6-7, and then adding an intercalating agent to form the rare earth hydrotalcite precursor solution;

[0044] Furthermore, the rare earth hydrotalcite precursor solution is subjected to a hydrothermal reaction at 90-150° C. for 8-12 hours to obtain the rare earth hydrotalcite.

[0045] In some more specific embodiments, the preparation method specifically includes:

[0046] dissolving the first rare earth metal salt and the second rare earth metal salt in a solvent to form a rare earth metal salt solution, adjusting the pH of the obtained rare earth metal salt solution to 6-7 to form the first mixed reaction system, and performing a hydrothermal reaction at 90-150° C. for 8-12 hours;

[0047] And, adding an intercalation agent to the obtained hydrothermal reaction product and performing a microwave intercalation reaction to obtain the rare earth hydrotalcite.

[0048] Furthermore, the molar ratio of the first rare earth metal salt to the second rare earth metal salt is 0.5-67:100.

[0049] Furthermore, the alkaline substance used to adjust the pH value of the rare earth metal salt solution includes any one of ammonia water, sodium hydroxide, and potassium hydroxide, or a combination of two or more thereof, but is not limited thereto.

[0050] Furthermore, the solvent includes nitric acid solution and / or sulfuric acid solution, but is not limited thereto.

[0051] In some more specific embodiments, the preparation method specifically includes: ultrasonically dispersing the rare earth hydrotalcite in water, then adding a platinum source for ultrasonic dispersion, and then heating the obtained mixed solution to 60-100° C. and reacting for 12-24 hours to obtain the rare earth hydrotalcite / platinum hydroxide complex.

[0052] Furthermore, the mass ratio of the rare earth hydrotalcite to the platinum source is 1.0-10:0.02-0.2.

[0053] Furthermore, the platinum source includes sodium chloroplatinate hexahydrate and / or sodium chloroplatinate hexahydrate, but is not limited thereto.

[0054] In some more specific embodiments, the preparation method specifically includes:

[0055] In a reducing atmosphere, the rare earth hydrotalcite / platinum hydroxide complex is heated to 500-1000° C. and subjected to the high-temperature annealing treatment for 0.5-2 hours. The obtained product is then immersed in a dilute acid solution, washed, and dried to obtain a two-dimensionally supported alloy catalyst similar to the hydrotalcite.

[0056] Furthermore, the preparation method comprises: heating the rare earth hydrotalcite / platinum hydroxide composite to 500-1000° C. at a heating rate of 5-10° C. / min.

[0057] Furthermore, the reducing atmosphere includes a mixed atmosphere of hydrogen and inert gas.

[0058] Furthermore, the volume percentage of hydrogen in the reducing atmosphere is 5-10%.

[0059] Furthermore, the dilute acid solution includes any one of dilute nitric acid, dilute sulfuric acid, and dilute perchloric acid, or a combination of two or more thereof, but is not limited thereto.

[0060] In some more specific embodiments, the preparation method of the hydrotalcite-like two-dimensional supported alloy catalyst specifically includes (preparation process as follows Figure 1 shown):

[0061] (1) Preparation of rare earth hydrotalcite (LDH) by hydrothermal method: two rare earth metal salts are dissolved in dilute nitric acid solution, the two rare earth metal salt solutions are mixed and stirred according to a certain doping ratio (0.5-40%), dilute ammonia solution is added dropwise thereto to adjust the pH to 6-7, and then an intercalation agent (benzoic acid, sodium dodecylbenzenesulfonate, sodium dodecylsulfonate, etc.) is added thereto to obtain a rare earth hydrotalcite precursor solution; the rare earth hydrotalcite precursor solution is transferred to a polytetrafluoroethylene-lined hydrothermal reactor, maintained at 90-150°C for 8-12 hours, and naturally cooled to collect the precipitate to obtain rare earth hydrotalcite;

[0062] (2) LDH / Pt(OH)4 complex was prepared by impregnation method: 0.1-1.0 g LDH was ultrasonically dispersed in 100 mL deionized water, 20-200 μL of 0.1 g / mL chloroplatinic acid hexahydrate aqueous solution was added thereto, and after water bath ultrasonication, the mixed solution was heated to 60-100 °C overnight, the precipitate was collected by centrifugation, washed three times with deionized water, and dried to obtain LDH / Pt(OH)4 complex;

[0063] (3) A high-temperature annealing method was used to prepare a two-dimensional hydrotalcite-like supported alloy catalyst: the LDH / Pt(OH)4 complex was annealed in a hydrogen atmosphere at a temperature of 500-1000°C and an annealing time of 0.5-2h. The annealed product was then soaked in a dilute H2SO4 solution overnight to remove the alloyed rare earth elements. The precipitate was then washed with deionized water until the supernatant was neutral and dried to obtain a two-dimensional hydrotalcite-like supported alloy catalyst (referred to as a two-dimensional supported Pt alloy catalyst).

[0064] Another aspect of the embodiments of the present invention further provides a hydrotalcite-like two-dimensional supported alloy catalyst prepared by the aforementioned method, wherein the loading amount of platinum element in the alloy catalyst is 5 to 60 wt %.

[0065] Furthermore, in the hydrotalcite-like two-dimensional supported alloy catalyst, the Pt alloy is uniformly distributed on the surface of the rare earth hydrotalcite.

[0066] Furthermore, the size of the Pt alloy in the hydrotalcite-like two-dimensional supported alloy catalyst is 4 to 6 nm.

[0067] Another aspect of the embodiments of the present invention further provides use of the aforementioned hydrotalcite-like two-dimensional supported alloy catalyst in the field of water electrolysis.

[0068] Another aspect of an embodiment of the present invention further provides a hydrogen evolution electrocatalyst, which comprises the aforementioned hydrotalcite-like two-dimensional supported alloy catalyst.

[0069] Furthermore, the hydrogen evolution electrocatalyst further comprises carbon black, the hydrotalcite-like two-dimensionally supported alloy catalyst is dispersed on the surface of the carbon black, and the loading amount of platinum element in the hydrogen evolution electrocatalyst is 1.0 to 12 wt%.

[0070] Another aspect of an embodiment of the present invention further provides a hydrogen evolution electrode, which comprises the aforementioned hydrotalcite-like two-dimensional supported alloy catalyst or hydrogen evolution electrocatalyst.

[0071] An embodiment of the present invention further provides a method for hydrogen evolution by electrolysis of water, comprising: in a reaction of preparing hydrogen by electrolysis of water, using the aforementioned hydrotalcite-like two-dimensional supported alloy catalyst or hydrogen evolution electrocatalyst as a hydrogen evolution electrocatalyst in the reaction.

[0072] Compared to direct alloying, the greatest advantage lies in its two-dimensional support. The hydrotalcite's original two-dimensional lamellae structure is retained after annealing. This two-dimensional substrate significantly facilitates mass and load transfer during hydrogen evolution, enhancing its activity. Furthermore, the two-dimensional structure inhibits the migration and aggregation of alloy particles during hydrogen evolution, thereby improving the catalyst's durability.

[0073] The present invention uniformly loads Pt alloy on a two-dimensional layered structure through chemical action, and is less likely to migrate and aggregate during long-term operation (compared with commercial Pt / C catalysts, the interaction between Pt and C is mostly physical adsorption, and the binding force is weaker); the two-dimensional structure has a larger specific surface area, which can increase the number of catalytic active sites, thereby improving catalytic activity. The two-dimensional structure is conducive to mass transfer and charge transfer, and enhances the kinetic performance of the reaction.

[0074] Compared with the alloy catalyst of the present invention, which directly alloys rare earth metals with Pt, the original two-dimensional flaky structure of the hydrotalcite in the two-dimensionally supported hydrotalcite-like alloy catalyst is retained after annealing. The two-dimensional substrate greatly promotes mass transfer and charge transfer during the hydrogen evolution process, thereby improving its activity. In addition, the two-dimensional structure can also inhibit the migration and aggregation of alloy particles during the hydrogen evolution process, thereby improving the durability of the catalyst.

[0075] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments and the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0076] Unless otherwise specified, the experimental materials used in the following examples can be purchased from conventional biochemical reagent companies.

[0077] Example 1

[0078] (1) Preparing rare earth hydrotalcite (LDH) by a hydrothermal method: yttrium (Y) salt and europium (Eu) salt are dissolved in a dilute nitric acid solution (wherein the molar ratio of yttrium salt to europium salt is 1:19), and then a dilute ammonia solution is added dropwise thereto to adjust the pH to 6-7, and then benzoic acid is added thereto to obtain a rare earth hydrotalcite precursor solution; the rare earth hydrotalcite precursor solution is transferred to a polytetrafluoroethylene-lined hydrothermal reactor, maintained at 120°C for 12 hours, and naturally cooled to collect the precipitate to obtain rare earth hydrotalcite;

[0079] (2) LDH / Pt(OH)4 complex was prepared by impregnation method: 0.1 g LDH was ultrasonically dispersed in 100 mL deionized water, 20 μL of 0.1 g / mL chloroplatinic acid hexahydrate aqueous solution was added thereto, and after water bath ultrasonication, the mixed solution was heated to 90 °C for 12 h. The precipitate was collected by centrifugation, washed three times with deionized water, and dried to obtain LDH / Pt(OH)4 complex;

[0080] (3) A high-temperature annealing method was used to prepare a two-dimensional hydrotalcite-like supported alloy catalyst: the LDH / Pt(OH)4 complex was annealed in a mixed atmosphere of hydrogen and argon at a temperature of 900°C for 2 h. The annealed product was then soaked in a dilute H2SO4 solution overnight to remove the alloyed rare earth elements. The precipitate was then washed with deionized water until the supernatant was neutral. The catalyst was dried to obtain a two-dimensional hydrotalcite-like supported alloy catalyst, which was designated as Y(Eu)-Pt.

[0081] Performance characterization:

[0082] The X-ray diffraction (XRD) patterns of the rare earth hydrotalcite and Y(Eu)-Pt alloy catalyst prepared in this example are as follows: Figure 2 As shown, from Figure 2 It can be seen that there is a characteristic peak of hydrotalcite at around 5°, which is caused by the interlayer spacing of hydrotalcite. The other peaks are XRD characteristic peaks of lanthanide hydrotalcite. After high-temperature annealing, the lanthanide metal alloys with Pt to form Pt alloy. The peaks around 40°, 47° and 68° in the XRD spectrum are respectively attributed to the (111), (200) and (220) crystal planes of the alloy;

[0083] Figure 3a-Figure 3b The scanning electron microscope (SEM) images of the rare earth hydrotalcite before and after intercalation in this embodiment are shown. It can be observed from the images that the unintercalated lanthanide hydrotalcite sheet is thicker, and after intercalation, the sheet becomes significantly thinner;

[0084] The transmission electron microscopy (TEM) of the Y(Eu)-Pt alloy catalyst prepared in this example is as follows: Figure 4 As shown, the black granular object is Pt alloy with a size of about 5 nm and a uniform size distribution. The light-colored substance is a two-dimensional carrier. It can be observed that the Pt alloy is evenly distributed on the surface of the two-dimensional carrier without agglomeration. Combined with XRD and TEM characterization, it can be proved that this method can be used to prepare a hydrotalcite-like two-dimensional loaded Pt alloy catalyst with uniform particle size and distribution.

[0085] When the Y(Eu)-Pt prepared in this example is used as a HER electrocatalyst, its LSV curve is as follows: Figure 5As shown in the figure, it can be observed that the HER activity of the Y(Eu)-Pt alloy catalyst is much better than that of the commercial Pt / C catalyst, showing a lower overpotential. -2 The overpotential is 14 mV, which is 40 mV lower than that of commercial Pt / C catalyst.

[0086] Cyclic performance test: Figure 6 The linear scan curves of the Y(Eu)-Pt alloy catalyst and the commercial Pt / C catalyst in this embodiment before and after the accelerated life test (the test method is cyclic voltammetry test). Figure 6 It can be seen that the catalytic activity of the commercial Pt / C catalyst is greatly reduced after 5000 cyclic voltammetry tests; while the catalytic activity of Y(Eu)-Pt remains almost unchanged after 10000 cyclic voltammetry tests, indicating that the prepared hydrotalcite-like two-dimensional supported alloy catalyst has good stability.

[0087] Example 2

[0088] (1) Rare earth hydrotalcite (LDH) was prepared by a hydrothermal method: lanthanum (La) salt and cerium (Ce) salt were dissolved in a dilute nitric acid solution (wherein the molar ratio of lanthanum salt to cerium salt was 1:9), and then a dilute ammonia solution was added dropwise thereto to adjust the pH to 6-7, and then benzoic acid was added thereto to obtain a rare earth hydrotalcite precursor solution; the rare earth hydrotalcite precursor solution was transferred to a polytetrafluoroethylene-lined hydrothermal reactor, maintained at 100°C for 10 hours, and naturally cooled to collect the precipitate to obtain rare earth hydrotalcite;

[0089] (2) LDH / Pt(OH)4 complex was prepared by impregnation method: 0.2 g LDH was ultrasonically dispersed in 100 mL deionized water, 50 μL of 0.1 g / mL chloroplatinic acid hexahydrate aqueous solution was added thereto, and after water bath ultrasonication, the mixed solution was heated to 80 °C for 18 h. The precipitate was collected by centrifugation, washed three times with deionized water, and dried to obtain LDH / Pt(OH)4 complex;

[0090] (3) A high-temperature annealing method was used to prepare a two-dimensional hydrotalcite-like supported alloy catalyst: the LDH / Pt(OH)4 complex was annealed in a mixed atmosphere of hydrogen and argon at a temperature of 700°C and an annealing time of 1.5 h. The annealed product was then soaked in a dilute H2SO4 solution overnight to remove the alloyed rare earth elements. The precipitate was then washed with deionized water until the supernatant was neutral. The catalyst was dried to obtain a two-dimensional hydrotalcite-like supported alloy catalyst, which was designated as La(Ce)-Pt.

[0091] Example 3

[0092] (1) Preparing rare earth hydrotalcite (LDH) by a hydrothermal method: yttrium (Y) salt and terbium (Tb) salt are dissolved in a dilute nitric acid solution (wherein the molar ratio of yttrium salt to terbium salt is 0.5:100), and then a dilute ammonia solution is added dropwise thereto to adjust the pH to 6-7, and then benzoic acid is added thereto to obtain a rare earth hydrotalcite precursor solution; the rare earth hydrotalcite precursor solution is transferred to a polytetrafluoroethylene-lined hydrothermal reactor, maintained at 90°C for 12 hours, and naturally cooled to collect the precipitate to obtain rare earth hydrotalcite;

[0093] (2) LDH / Pt(OH)4 complex was prepared by impregnation method: 0.15 g LDH was ultrasonically dispersed in 100 mL deionized water, 45 μL of 0.1 g / mL chloroplatinic acid hexahydrate aqueous solution was added thereto, and after water bath sonication, the mixed solution was heated to 60 °C and reacted for 24 h. The precipitate was collected by centrifugation, washed three times with deionized water, and dried to obtain LDH / Pt(OH)4 complex;

[0094] (3) A high-temperature annealing method was used to prepare a two-dimensional hydrotalcite-like supported alloy catalyst: the LDH / Pt(OH)4 complex was annealed in a mixed atmosphere of hydrogen and argon at a temperature of 500°C for 2 h. The annealed product was then soaked in a dilute H2SO4 solution overnight to remove the alloyed rare earth elements. The precipitate was then washed with deionized water until the supernatant was neutral. The catalyst was dried to obtain a two-dimensional hydrotalcite-like supported alloy catalyst, which was designated as Y(Tb)-Pt.

[0095] Example 4

[0096] (1) Rare earth hydrotalcite (LDH) was prepared by a hydrothermal method: gadolinium (Gd) salt and europium (Eu) salt were dissolved in a dilute nitric acid solution (wherein the molar ratio of gadolinium salt to europium salt was 1:1), and then a dilute ammonia solution was added dropwise thereto to adjust the pH to 6-7, and then benzoic acid was added thereto to obtain a rare earth hydrotalcite precursor solution; the rare earth hydrotalcite precursor solution was transferred to a polytetrafluoroethylene-lined hydrothermal reactor, maintained at 120°C for 8 hours, and naturally cooled to collect the precipitate to obtain rare earth hydrotalcite;

[0097] (2) LDH / Pt(OH)4 complex was prepared by impregnation method: 0.2 g LDH was ultrasonically dispersed in 100 mL deionized water, 40 μL of 0.1 g / mL chloroplatinic acid hexahydrate aqueous solution was added thereto, and after water bath sonication, the mixed solution was heated to 85 °C for 16 h. The precipitate was collected by centrifugation, washed three times with deionized water, and dried to obtain LDH / Pt(OH)4 complex;

[0098] (3) A high-temperature annealing method was used to prepare a hydrotalcite-like two-dimensional supported alloy catalyst: the LDH / Pt(OH)4 complex was annealed in a mixed atmosphere of hydrogen and argon at a temperature of 750°C and an annealing time of 1.5 h. The annealed product was then soaked in a dilute H2SO4 solution overnight to remove the alloyed rare earth elements. The precipitate was then washed with deionized water until the supernatant was neutral. The catalyst was dried to obtain a hydrotalcite-like two-dimensional supported alloy catalyst, which was designated as Gd(Eu)-Pt.

[0099] Example 5

[0100] (1) Preparing rare earth hydrotalcite (LDH) by a hydrothermal method: dissolving gadolinium (Gd) salt and terbium (Tb) salt in a dilute nitric acid solution (wherein the molar ratio of gadolinium salt to terbium salt is 67:100), then adding a dilute ammonia solution to adjust the pH to 6-7, and then adding benzoic acid to obtain a rare earth hydrotalcite precursor solution; transferring the rare earth hydrotalcite precursor solution to a polytetrafluoroethylene-lined hydrothermal reactor, maintaining the temperature at 150°C for 8 hours, and naturally cooling to collect the precipitate to obtain rare earth hydrotalcite;

[0101] (2) LDH / Pt(OH)4 complex was prepared by impregnation method: 0.5 g LDH was ultrasonically dispersed in 100 mL deionized water, 100 μL of 0.1 g / mL chloroplatinic acid hexahydrate aqueous solution was added thereto, and after water bath ultrasonication, the mixed solution was heated to 100 °C for 12 h. The precipitate was collected by centrifugation, washed three times with deionized water, and dried to obtain LDH / Pt(OH)4 complex;

[0102] (3) A high-temperature annealing method was used to prepare a hydrotalcite-like two-dimensional supported alloy catalyst: the LDH / Pt(OH)4 complex was annealed in a mixed atmosphere of hydrogen and argon at a temperature of 1000°C and an annealing time of 0.5 h. The annealed product was then soaked in a dilute H2SO4 solution overnight to remove the alloyed rare earth elements. The precipitate was then washed with deionized water until the supernatant was neutral. The catalyst was dried to obtain a hydrotalcite-like two-dimensional supported alloy catalyst, which was designated as Gd(Tb)-Pt.

[0103] Example 6

[0104] (1) Preparation of rare earth hydrotalcite (LDH) by hydrothermal method: lanthanum (La) salt and cerium (Ce) salt were dissolved in dilute nitric acid solution (wherein the molar ratio of lanthanum salt to cerium salt was 1:3), and then dilute ammonia solution was added dropwise to adjust the pH to 6-7. The rare earth hydrotalcite precursor solution was transferred to a polytetrafluoroethylene-lined hydrothermal reactor and maintained at 120°C for 12 hours. Then, sodium dodecylbenzenesulfonate was added to the obtained product and microwave intercalation reaction was carried out to obtain rare earth hydrotalcite;

[0105] (2) LDH / Pt(OH)4 complex was prepared by impregnation method: 0.1 g LDH was ultrasonically dispersed in 100 mL deionized water, 20 μL of 0.1 g / mL chloroplatinic acid hexahydrate aqueous solution was added thereto, and after water bath sonication, the mixed solution was heated to 90 °C for 20 h. The precipitate was collected by centrifugation, washed three times with deionized water, and dried to obtain LDH / Pt(OH)4 complex;

[0106] (3) A high-temperature annealing method was used to prepare a two-dimensional hydrotalcite-like supported alloy catalyst: the LDH / Pt(OH)4 complex was annealed in a mixed atmosphere of hydrogen and argon at a temperature of 1000°C for 2 h. The annealed product was then soaked in a dilute H2SO4 solution overnight to remove the alloyed rare earth elements. The precipitate was then washed with deionized water until the supernatant was neutral. The catalyst was dried to obtain a two-dimensional hydrotalcite-like supported alloy catalyst, which was designated as La(Ce)-Pt.

[0107] In addition, the present invention is compared with the Pt alloy catalysts in the prior art, for example, the overpotential of NiFe LDH-Pt in the document Holey PtNanosheets on NiFe-Hydroxide Laminates: Synergistically EnhancedElectrocatalytic 2D Interface toward Hydrogen Evolution Reaction.ACS Nano2020, 14, 8, 10578-10588 is 31mV; the overpotential of NiRu LDH-Pt in the document An effective hybrid electrocatalyst for the alkaline HER: Highly dispersed Pt sites immobilized bya functionalized NiRu-hydroxide.Applied Catalysis B-Environmental 2020, 269, 118824. is 38mV; the overpotential of NiFe in the document Enhancing electrocatalytic totalwater splitting at few layer Pt-NiFe layered double hydroxide interfaces.NanoEnergy 2017, 39, 30-43 is 38mV. The overpotential of LDH-Pt-ht is 101 mV; the overpotential of the Y(Eu)-Pt alloy catalyst prepared in this Example 1 is 14 mV, showing a lower overpotential.

[0108] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments using other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0109] It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical variations made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a hydrotalcite-like two-dimensional supported alloy catalyst, characterized in that include: A rare earth hydrotalcite precursor solution comprising a first rare earth metal salt, a second rare earth metal salt, an intercalating agent, and a solvent is subjected to a hydrothermal reaction to produce the rare earth hydrotalcite; or a first mixed reaction system comprising the first rare earth metal salt, the second rare earth metal salt, and a solvent is subjected to a hydrothermal reaction, followed by adding an intercalating agent to the resulting hydrothermal reaction product and subjecting it to a microwave intercalation reaction to produce the rare earth hydrotalcite; wherein the first rare earth metal salt and the second rare earth metal salt are two different rare earth metal salts; immersing the rare earth hydrotalcite in a solution containing a platinum source to react and form a rare earth hydrotalcite / platinum hydroxide complex; Furthermore, the rare earth hydrotalcite / platinum hydroxide composite is subjected to high-temperature annealing treatment in a reducing atmosphere to obtain a hydrotalcite-like two-dimensional supported alloy catalyst.

2. The preparation method according to claim 1, wherein: The first rare earth metal salt and the second rare earth metal salt are independently selected from any one of scandium salts, yttrium salts, and lanthanide metal salts; the lanthanide metal salts include any one of lanthanum salts, cerium salts, praseodymium salts, neodymium salts, promethium salts, samarium salts, europium salts, gadolinium salts, terbium salts, dysprosium salts, holmium salts, erbium salts, thulium salts, ytterbium salts, and lutetium salts; And / or, the intercalant includes any one of benzoic acid, sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate, or a combination of two or more thereof.

3. The preparation method according to claim 2, wherein Specifically include: dissolving a first rare earth metal salt and a second rare earth metal salt in a solvent to form a rare earth metal salt solution, adjusting the pH value of the obtained rare earth metal salt solution to 6-7, and then adding an intercalating agent to form the rare earth hydrotalcite precursor solution; and subjecting the rare earth hydrotalcite precursor solution to a hydrothermal reaction at 90-150° C. for 8-12 hours to obtain the rare earth hydrotalcite; And / or, the preparation method specifically comprises: dissolving the first rare earth metal salt and the second rare earth metal salt in a solvent to form a rare earth metal salt solution, then adjusting the pH value of the obtained rare earth metal salt solution to 6-7 to form the first mixed reaction system, and performing a hydrothermal reaction at 90-150° C. for 8-12 hours; And, adding an intercalation agent to the obtained hydrothermal reaction product and performing a microwave intercalation reaction to obtain the rare earth hydrotalcite.

4. The preparation method according to claim 3, wherein: The molar ratio of the first rare earth metal salt to the second rare earth metal salt is 0.5-67:100; And / or, the alkaline substance used to adjust the pH value of the rare earth metal salt solution includes any one of ammonia water, sodium hydroxide, and potassium hydroxide, or a combination of two or more thereof; And / or, the solvent includes nitric acid solution and / or sulfuric acid solution.

5. The preparation method according to claim 1, characterized in that Specifically include: The rare earth hydrotalcite is ultrasonically dispersed in water, a platinum source is then added and ultrasonically dispersed, and the resulting mixture is heated to 60-100° C. and reacted for 12-24 hours to prepare the rare earth hydrotalcite / platinum hydroxide complex; the mass ratio of the rare earth hydrotalcite to the platinum source is 1.0-10:0.02-0.2; and the platinum source includes sodium chloroplatinate hexahydrate and / or sodium chloroplatinate hexahydrate.

6. The preparation method according to claim 1, characterized in that Specifically include: In a reducing atmosphere, heating the rare earth hydrotalcite / platinum hydroxide complex to 500-1000° C. at a heating rate of 5-10° C. / min, performing the high-temperature annealing treatment for 0.5-2 hours, and then soaking the obtained product in a dilute acid solution, washing, and drying to obtain the hydrotalcite-like two-dimensional supported alloy catalyst; The reducing atmosphere comprises a mixed atmosphere of hydrogen and an inert gas; the volume percentage of hydrogen in the reducing atmosphere is 5 to 10%; and the dilute acid solution comprises any one of dilute nitric acid, dilute sulfuric acid, and dilute perchloric acid, or a combination of two or more thereof.

7. A hydrotalcite-like two-dimensional supported alloy catalyst prepared by the method according to any one of claims 1 to 6, characterized in that: The loading amount of platinum element in the alloy catalyst is 5-60wt%; the Pt alloy in the hydrotalcite-like two-dimensional supported alloy catalyst is uniformly distributed on the surface of rare earth hydrotalcite; the size of the Pt alloy in the hydrotalcite-like two-dimensional supported alloy catalyst is 4-6nm.

8. Use of the hydrotalcite-like two-dimensionally supported alloy catalyst according to claim 7 in hydrogen evolution reaction by water electrolysis.

9. A hydrogen evolution electrocatalyst, characterized in that An alloy catalyst comprising the hydrotalcite-like two-dimensional support according to claim 7; The hydrogen evolution electrocatalyst further comprises carbon black, the hydrotalcite-like two-dimensionally supported alloy catalyst is dispersed on the surface of the carbon black, and the loading amount of the platinum element in the hydrogen evolution electrocatalyst is 1.0-12 wt %.

10. A hydrogen evolution electrode, characterized in that Comprising the hydrotalcite-like two-dimensional supported alloy catalyst according to claim 7 or the hydrogen evolution electrocatalyst according to claim 9.

11. A method for hydrogen evolution by electrolysis of water, characterized in that include: In the reaction of producing hydrogen by electrolysis of water, the hydrotalcite-like two-dimensional supported alloy catalyst according to claim 7 or the hydrogen evolution electrocatalyst according to claim 9 is used as the hydrogen evolution electrocatalyst in the reaction.

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