Layered transition metal hydroxide catalyst as well as macro preparation method and application thereof

Abstract

The invention relates to the field of electro-catalytic materials, and particularly discloses a layered transition metal hydroxide catalyst as well as a macro-quantity preparation method and application thereof. According to the method, the nanoparticles are formed through solvent difference induction, the nanoparticles are adsorbed on the foamed nickel substrate, formation of the layered transition metal hydroxide on the foamed nickel substrate is promoted, the layered transition metal hydroxide is prepared through a heterogeneous nucleation mechanism, and compared with a traditional homogeneous nucleation process, disordered aggregation of the nanoparticles can be effectively prevented; the preparation method has the advantages of high dispersity and uniform structure, the preparation method does not depend on conditions such as high temperature and high pressure, the equipment cost, energy consumption and safety risk can be reduced, and the method has universality and environmental friendliness and can be applied to macroscopic preparation of the catalyst with good uniformity.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic materials technology, specifically relating to a layered transition metal hydroxide catalyst, its large-scale preparation method, and its application. Background Technology

[0002] With the global energy structure transformation, the development of efficient, stable and low-cost electrocatalysts has become one of the core challenges of many energy conversion technologies, including water electrolysis for hydrogen production, fuel cells, and metal-air batteries.

[0003] Layered transition metal hydroxides, as typical two-dimensional layered materials, have attracted widespread attention in the field of electrocatalysis in recent years due to their unique tunable layered structure, abundant exposed active sites, excellent chemical stability, and low cost. The general chemical formula for layered transition metal hydroxides is M0. x (OH) y Its layers are composed of octahedral hydroxides of divalent and trivalent metal ions connected by common edges, and the charge balance between the layers is maintained by the intercalation of exchangeable anions and water molecules. This structure gives it the following advantages: (1) the electronic structure can be optimized by controlling the types and proportions of metal elements such as Fe, Co, Ni, and Mn; (2) the exposed active sites can effectively participate in surface electrochemical reactions; (3) the interlayer domains can act as "nanoreactors" to promote mass transfer processes; (4) the flexible layered structure is conducive to stress release and improves cycle stability. At present, layered bimetallic hydroxides (LDHs) have shown significant potential in oxygen evolution reaction (OER), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and carbon dioxide reduction reaction (CO2RR). For example, NiFe-LDH is recognized as one of the best-performing non-noble metal OER catalysts under alkaline conditions.

[0004] Currently, the main laboratory methods for preparing layered bimetallic hydroxides (LDHs) include coprecipitation, sol-gel, hydrothermal, and urea hydrolysis. Among these, urea hydrolysis is a commonly used synthetic method for preparing self-supporting layered transition metal double hydroxides in the laboratory. In-situ characterization techniques have confirmed that the NH3 and CO3 produced by urea hydrolysis... 2- This method allows for precise control of solution pH, enabling gradient co-precipitation of metal ions. It effectively avoids the formation of impurity phases caused by localized supersaturation, thereby improving the efficiency of ordered co-precipitation of metal ions between layers. Simultaneously, the uniform release of CO32- allows for precise control of the distribution of anions between layers, endowing LDH with high crystallinity, a regular layered structure, and a large specific surface area. Furthermore, this method requires no complex equipment or costly additives; by adjusting the urea / metal salt molar ratio and reaction time, the thickness, particle size, and pore structure of LDH can be precisely controlled, making it particularly suitable for the preparation of polymetallic hydroxides.

[0005] However, laboratory-scale synthesis methods typically rely on precise control of pH, temperature, and ion concentration. In large-scale preparation, the mixing efficiency of the reaction system is low, and the mass and heat transfer is uneven, which can easily lead to uneven interlayer structure of the double hydroxide, decreased crystallinity, or the formation of impurity phases, resulting in many defects in large-scale preparation. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention aims to provide a catalyst for layered transition metal hydroxides, a method for its large-scale preparation, and its application, so as to solve the problem that common laboratory preparation methods such as urea hydrolysis cannot be used to prepare layered transition metal hydroxides on a large scale.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A catalyst for layered transition metal hydroxides, based on the difference in solubility of sulfates and nitrates in organic solutions, forms insoluble nanoparticles that adsorb onto the substrate surface, reduce the substrate surface energy, and promote the formation of layered transition metal hydroxides.

[0009] Preferably, layered transition metal hydroxides are formed based on the difference in solubility of sulfates and nitrates in organic solutions.

[0010] Preferably, an intermediate layer for anchoring the layered transition metal hydroxide is formed between the insoluble nanoparticles and the substrate.

[0011] Preferably, the layered transition metal hydroxide contains SO4 to suppress the dissolution reaction of metal ions at high oxidation potentials. 2- The ion, the chemical formula of the layered transition metal hydroxide is M(SO4). x (OH) y (H2O) z M represents metal, and x, y, and z represent numbers greater than zero.

[0012] A method for the large-scale preparation of a layered transition metal hydroxide catalyst, comprising the following steps:

[0013] S1. Dissolve the metal sulfate in ultrapure water and stir magnetically until completely dissolved to obtain solution A. Dissolve the nitrate in an organic solution and stir magnetically until completely dissolved to obtain solution B.

[0014] S2. Under magnetic stirring, solution A is added dropwise to solution B to obtain solution C;

[0015] S3. Place the substrate in solution C for reaction. The substrate includes nickel foam, copper foam, iron foam, cobalt foam, nickel mesh, and titanium mesh. After the reaction is terminated, remove the substrate and rinse it alternately with ethanol and ultrapure water. Place the rinsed substrate in a vacuum drying oven for drying to obtain a layered transition metal hydroxide electrode.

[0016] Preferably, the metal sulfate feed ratio is ≥10%, and the nitrate feed ratio is ≤90%.

[0017] Preferably, the synthesis temperature condition for placing the substrate in solution C for reaction is room temperature.

[0018] A method for the large-scale preparation of layered transition metal hydroxide catalysts, applicable to the preparation of monometallic, bimetallic, and multimetallic hydroxide electrodes.

[0019] Application of a layered transition metal hydroxide catalyst in the field of electrocatalysis, including water electrolysis for hydrogen production and electro-oxidation of organic matter.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This invention induces the formation of nanoparticles through solvent difference. These nanoparticles adsorb onto a nickel foam substrate, promoting the formation of layered transition metal hydroxides on the substrate. By preparing layered transition metal hydroxides through a heterogeneous nucleation mechanism, compared to the traditional homogeneous nucleation process, this method effectively prevents the disordered aggregation of nanoparticles, thus ensuring that the product has a highly dispersed and uniform structure. Moreover, the preparation method does not rely on high temperature and high pressure conditions, which can reduce equipment costs, energy consumption, and safety risks. Furthermore, this method is universal and environmentally friendly, and can be applied to the large-scale preparation of catalysts with good uniformity. Attached Figure Description

[0022] Figure 1 This is a block diagram of a method for the large-scale preparation of a layered transition metal hydroxide catalyst disclosed in this invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] A catalyst for layered transition metal hydroxides, based on the difference in solubility of sulfates and nitrates in organic solutions, forms insoluble nanoparticles that adsorb onto the surface of nickel foam, reduce the surface energy of nickel foam, and promote the formation of layered transition metal hydroxides. Layered transition metal hydroxides are formed on the surface of nickel foam, and an intermediate layer for anchoring the layered transition metal hydroxides is formed between the insoluble nanoparticles and the nickel foam.

[0025] The core mechanism of preparing layered metal hydroxides using heterogeneous nucleation technology lies in the fact that when metal nitrates and sulfates dissolve in a mixture of organic solvents such as isopropanol and water, insoluble particles precipitate due to their differences in solubility. These nanoparticles are uniformly adsorbed onto the surface of the pretreated nickel foam substrate, effectively reducing the interfacial energy by providing a ready-made heterogeneous nucleation interface, thereby accelerating the growth of the subsequent catalyst layer.

[0026] The prepared layered metal hydroxide functional materials have the following three significant characteristics: First, the prepared self-supporting layered transition metal hydroxides contain SO4 in the interlayer. 2- An ion with the chemical formula M(SO4). x (OH) y (H2O) z This is beneficial for improving the activity and chemical stability of layered rare earth hydroxide electrodes in water electrolysis and small molecule oxidation of organic matter; the second significant feature is that insoluble nanoparticles first form a dense metal hydroxide intermediate layer on the pretreated substrate, such as nickel foam, which anchors the metal hydroxide catalyst layer. The resulting intermediate layer structure can enhance the mechanical stability of the catalyst in the gas evolution reaction; the third significant feature is that this heterogeneous nucleation method is not only low-cost and energy-saving, but also enables the large-scale preparation of catalysts.

[0027] The layered transition metal hydroxide contains SO4, which helps suppress the dissolution reaction of metal ions at high oxidation potentials. 2- The ion, the chemical formula of the layered transition metal hydroxide is M(SO4). x (OH) y (H2O) z M represents metal, and x, y, and z represent numbers greater than zero.

[0028] Please see Figure 1 A method for the large-scale preparation of a layered transition metal hydroxide catalyst, comprising the following steps:

[0029] S1. Dissolve an appropriate amount of metal sulfate in ultrapure water and stir magnetically until completely dissolved to obtain solution A. Solution A is a metal sulfate solution. The purity of the ultrapure water is 18.2 MΩ·cm. The metal sulfates are cobalt sulfate, copper sulfate, nickel sulfate, ferrous sulfate, manganese sulfate, zinc sulfate, chromium sulfate, and cadmium sulfate, etc. Dissolve nitrates in an organic solution. The organic solution is isopropanol with a concentration of 99% or higher. The metal nitrates are ferric nitrate, copper nitrate, zinc nitrate, nickel nitrate, cobalt nitrate, chromium nitrate, manganese nitrate, cadmium nitrate, palladium nitrate, and vanadium nitrate, etc. Stir magnetically until completely dissolved to obtain solution B.

[0030] S2. Under magnetic stirring conditions, solution A is added dropwise to solution B to obtain solution C, which is a heterogeneous nucleation solution. The feed ratio of the metal sulfate is ≥10%, and the feed ratio of the nitrate is ≤90%.

[0031] S3. Place the pretreated substrate in solution C. The substrate may be nickel foam, copper foam, iron foam, cobalt foam, nickel mesh, titanium mesh, etc. Let it stand at room temperature for 10-100 hours. The reaction time is adjusted according to the thickness of the dense layer and the catalyst layer. After the reaction is terminated, take out the substrate and rinse it alternately with ethanol and ultrapure water. Place the rinsed substrate in a vacuum drying oven to dry it to obtain a layered transition metal hydroxide electrode. The drying temperature is 30℃-120℃.

[0032] In the above preparation method, ultrapure water, as a polar solvent, plays a triple role: it dissolves the metal sulfate precursor, regulates the nucleation size and distribution of nanoparticles, and participates in the hydrolysis growth process of the catalyst layer. Isopropanol, as an organic solvent, performs a triple regulatory function: first, it serves as a solvent to form the metal nitrate solution; second, it reduces the solubility of the metal sulfate and induces the directional precipitation of nanoparticles by regulating solvent polarity; and third, it optimizes the microstructure of the catalyst layer and the adhesion to the substrate. Furthermore, the mixed solvent system of water and isopropanol can form a unique "polar-nonpolar" micro-interface, promoting the rapid binding of metal ions at the phase interface to form uniformly sized nanoparticles. Compared to traditional homogeneous nucleation processes, this heterogeneous nucleation mechanism effectively suppresses the random aggregation of nanoparticles, ensuring excellent dispersibility and structural consistency of the product.

[0033] A method for the large-scale preparation of layered transition metal hydroxide catalysts, applicable to the preparation of monometallic, bimetallic, and multimetallic hydroxide electrodes.

[0034] Application of layered transition metal hydroxide catalysts in the field of electrocatalysis, including water electrolysis for hydrogen production and electrooxidation of organic compounds.

[0035] Example 1:

[0036] Please see Figure 1 ,

[0037] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0038] (ii) Weigh 2.85g of Co(NO3)2·6H2O and dissolve it in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.41g of CoSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0039] (iii) Slowly add the dissolved CoSO4·7H2O dropwise into the Co(NO3)2·6H2O solution.

[0040] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0041] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0042] Example 2:

[0043] Please see Figure 1 ,

[0044] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0045] (ii) Weigh 3.96g of Fe(NO3)3·9H2O and dissolve it in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.41g of FeSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0046] (iii) Slowly add the dissolved FeSO4·7H2O dropwise into the Fe(NO3)3·9H2O solution.

[0047] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0048] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0049] Example 3:

[0050] Please see Figure 1 ,

[0051] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0052] (ii) Weigh 2.85g of Ni(NO3)2·6H2O and dissolve it in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.39g of NiSO4·6H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0053] (iii) Slowly add the dissolved NiSO4·6H2O dropwise into the Ni(NO3)2·6H2O solution.

[0054] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0055] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0056] Example 4:

[0057] Please see Figure 1 ,

[0058] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0059] (ii) Weigh 2.91g of Zn(NO3)2·6H2O and dissolve it in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.42g of ZnSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0060] (iii) Slowly add the dissolved ZnSO4·7H2O dropwise into the Zn(NO3)2·6H2O solution.

[0061] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0062] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0063] Example 5:

[0064] Please see Figure 1 ,

[0065] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0066] (ii) Weigh 2.46g of Mn(NO3)2·4H2O and dissolve it in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.25g of MnSO4·H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0067] (iii) Slowly add the dissolved MnSO4·H2O dropwise into the Mn(NO3)2·4H2O solution.

[0068] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0069] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0070] Example 6:

[0071] Please see Figure 1 ,

[0072] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0073] (ii) Weigh 2.85g of Co(NO3)2·6H2O and dissolve it in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.39g of FeSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0074] (iii) Slowly add the dissolved FeSO4·7H2O dropwise into the Co(NO3)2·6H2O solution.

[0075] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0076] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0077] Example 7:

[0078] Please see Figure 1 ,

[0079] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0080] (ii) Weigh 2.85g of Ni(NO3)2·6H2O and dissolve it in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.39g of FeSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0081] (iii) Slowly add the dissolved FeSO4·7H2O dropwise into the Ni(NO3)2·6H2O solution.

[0082] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0083] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0084] Example 8:

[0085] Please see Figure 1 ,

[0086] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0087] (ii) Weigh 2.37g of Cu(NO3)2·3H2O and dissolve it in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.39g of FeSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0088] (iii) Slowly add the dissolved FeSO4·7H2O dropwise into the Cu(NO3)2·3H2O solution.

[0089] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0090] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0091] Example 9:

[0092] Please see Figure 1 ,

[0093] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0094] (ii) Weigh 2.46g of Mn(NO3)2·4H2O and dissolve it in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.39g of FeSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0095] (iii) Slowly add the dissolved FeSO4·7H2O dropwise into the Mn(NO3)2·4H2O solution.

[0096] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0097] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0098] Example 10:

[0099] Please see Figure 1 ,

[0100] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0101] (ii) Weigh 2.91g of Zn(NO3)2·6H2O and dissolve it in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.39g of FeSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0102] (iii) Slowly add the dissolved FeSO4·7H2O dropwise to the Zn(NO3)2·6H2O solution.

[0103] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0104] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0105] Example 11:

[0106] Please see Figure 1 ,

[0107] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0108] (ii) Weigh 1.15g Cu(NO3)2·3H2O and 1.92g Fe(NO3)3·9H2O and dissolve them in 96mL isopropanol. Stir magnetically until completely dissolved. Weigh 0.47g CoSO4·7H2O and dissolve it in 16mL deionized water. Stir until completely homogeneous.

[0109] (iii) Slowly add the dissolved CoSO4·7H2O dropwise into a mixed solution of Fe(NO3)3·9H2O and Cu(NO3)2·3H2O.

[0110] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0111] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0112] Example 12:

[0113] Please see Figure 1 ,

[0114] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0115] (ii) Weigh 1.24g of Zn(NO3)2·6H2O and 1.15g of Cu(NO3)2·3H2O and dissolve them in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.47g of CoSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0116] (iii) Slowly add the dissolved CoSO4·7H2O dropwise into a mixed solution of Zn(NO3)2·6H2O and Cu(NO3)2·3H2O.

[0117] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0118] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0119] Example 13:

[0120] Please see Figure 1 ,

[0121] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0122] (ii) Weigh 1.19g of Mn(NO3)2·4H2O and 1.15g of Cu(NO3)2·3H2O and dissolve them in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.47g of CoSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0123] (iii) Slowly add the dissolved CoSO4·7H2O dropwise into a mixed solution of Mn(NO3)2·4H2O and Cu(NO3)2·3H2O.

[0124] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0125] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0126] Example 14:

[0127] Please see Figure 1 ,

[0128] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0129] (ii) Weigh 1.39g of Ni(NO3)2·6H2O and 1.15g of Cu(NO3)2·3H2O and dissolve them in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.47g of CoSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0130] (iii) Slowly add the dissolved CoSO4·7H2O dropwise into a mixed solution of Ni(NO3)2·6H2O and Cu(NO3)2·3H2O.

[0131] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0132] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0133] Example 15:

[0134] Please see Figure 1 ,

[0135] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0136] (ii) Weigh 1.38g of Co(NO3)2·6H2O and 1.15g of Cu(NO3)2·3H2O and dissolve them in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.46g of FeSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0137] (iii) Slowly add the dissolved FeSO4·7H2O dropwise into a mixed solution of Co(NO3)2·6H2O and Cu(NO3)2·3H2O.

[0138] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0139] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0140] Example 16:

[0141] Please see Figure 1 ,

[0142] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0143] (ii) Weigh 1.38g of Co(NO3)2·6H2O and 1.24g of Zn(NO3)2·6H2O and dissolve them in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.46g of FeSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0144] (iii) Slowly add the dissolved FeSO4·7H2O dropwise into a mixed solution of Co(NO3)2·6H2O and Zn(NO3)2·6H2O.

[0145] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0146] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0147] Example 17:

[0148] Please see Figure 1 ,

[0149] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0150] (ii) Weigh 1.38g of Co(NO3)2·6H2O and 1.19g of Mn(NO3)2·4H2O and dissolve them in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.46g of FeSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0151] (iii) Slowly add the dissolved FeSO4·7H2O dropwise into a mixed solution of Co(NO3)2·6H2O and Mn(NO3)2·4H2O.

[0152] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0153] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0154] Example 18:

[0155] Please see Figure 1 ,

[0156] (a) Cut the foamed nickel substrate, ultrasonically clean it with ethanol for 5-6 minutes to remove surface impurities, and dry it in an oven for later use.

[0157] (ii) Weigh 1.38g of Co(NO3)2·6H2O and 1.39g of Ni(NO3)2·6H2O and dissolve them in 96mL of isopropanol. Stir magnetically until completely dissolved. Weigh 0.46g of FeSO4·7H2O and dissolve it in 16mL of deionized water. Stir until completely homogeneous.

[0158] (iii) Slowly add the dissolved FeSO4·7H2O dropwise into a mixed solution of Co(NO3)2·6H2O and Ni(NO3)2·6H2O.

[0159] (iv) Add the cleaned nickel foam substrate to the above solution and stir magnetically for 31 hours.

[0160] (v) Remove the nickel foam substrate and dry it in an oven at 70°C for 12 hours to form a self-supporting transition metal layered double hydroxide.

[0161] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified.

[0162] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above 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 one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0163] The accompanying drawings of the embodiments disclosed in this invention only involve structures relevant to the embodiments disclosed in this invention. Other structures can be referred to with common designs. Unless otherwise specified, the same embodiment and different embodiments of this invention can be combined with each other.

Claims

1. A catalyst of layered transition metal hydroxides, characterized in that, Based on the difference in solubility of sulfates and nitrates in organic solutions, insoluble nanoparticles are formed that adsorb onto the substrate surface, reduce the substrate surface energy, and promote the formation of layered transition metal hydroxides.

2. The catalyst of a layered transition metal hydroxide according to claim 1, characterized in that, Layered transition metal hydroxides are formed based on the difference in solubility of sulfates and nitrates in organic solutions.

3. The catalyst of a layered transition metal hydroxide according to claim 1, characterized in that: An intermediate layer for anchoring the layered transition metal hydroxide is formed between the insoluble nanoparticles and the substrate.

4. The catalyst of a layered transition metal hydroxide according to claim 1, characterized in that, The layered transition metal hydroxide contains SO4, which helps suppress the dissolution reaction of metal ions at high oxidation potentials. 2- The ion, the chemical formula of the layered transition metal hydroxide is M(SO4). x (OH) y (H2O) z M represents metal, and x, y, and z represent numbers greater than zero.

5. A method for the large-scale preparation of a layered transition metal hydroxide catalyst, characterized in that, The preparation steps include: S1. Dissolve the metal sulfate in ultrapure water and stir magnetically until completely dissolved to obtain solution A. Dissolve the nitrate in an organic solution and stir magnetically until completely dissolved to obtain solution B. S2. Under magnetic stirring, solution A is added dropwise to solution B to obtain solution C; S3. Place the substrate in solution C for reaction. The substrate includes nickel foam, copper foam, iron foam, cobalt foam, nickel mesh, and titanium mesh. After the reaction is terminated, remove the substrate and rinse it alternately with ethanol and ultrapure water. Place the rinsed substrate in a vacuum drying oven for drying to obtain a layered transition metal hydroxide electrode.

6. The method for large-scale preparation of a layered transition metal hydroxide catalyst according to claim 5, characterized in that: The feed ratio of the metal sulfate is ≥10%, and the feed ratio of the nitrate is ≤90%.

7. The method for large-scale preparation of a layered transition metal hydroxide catalyst according to claim 5, characterized in that: The synthesis temperature condition for placing the substrate in solution C for reaction is room temperature.

8. A method for the large-scale preparation of a catalyst of layered transition metal hydroxide as described in any one of claims 5-7, characterized in that, It is used to prepare monometallic, bimetallic and polymetallic hydroxide electrodes.

9. The application of a layered transition metal hydroxide catalyst as described in any one of claims 1-4 in the field of electrocatalysis, wherein the electrocatalysis field includes water electrolysis for hydrogen production and organic electrooxidation reactions.

Images