Nanometer spherical NiFe-LDH (at) M (at) Cu oxygen evolution composite material and preparation method and application thereof

Abstract

The invention relates to a nano spherical NiFe-LDH (at) M (at) Cu oxygen evolution composite material and a preparation method and application thereof. The composite material comprises a copper substrate, a metal functional layer M is arranged on the copper substrate, a NiFe-LDH active layer is arranged on the metal functional layer M, and the NiFe-LDH active layer comprises nano spherical NiFe-LDH. The metal functional layer M comprises an anti-corrosion functional layer, and a catalytic structure layer is further arranged on the anti-corrosion functional layer. The metal functional layer M and the NiFe-LDH active layer are sequentially deposited on a pretreated copper substrate, so that the NiFe-LDH composite material is obtained. Wherein the anti-corrosion function layer can enhance the corrosion resistance of the base material, the catalytic structure layer can increase the active surface of the catalyst and provide support for the catalytic layer, meanwhile, the high conductivity of copper can be reserved, and the nano spherical NiFe-LDH has the large active surface area. Compared with the prior art, the NiFe-LDH-coated M-coated Cu prepared by the method has the advantages of low cost, high performance and stable structure, and is suitable for large-scale application on industrial conditions.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts for oxygen evolution in alkaline water electrolysis, and in particular to a nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material and a preparation method and application thereof. Background Art

[0002] With the transformation of the global energy structure and the increasingly urgent need for environmental protection, the development of sustainable clean energy has become an important direction for future development. As an ideal clean energy source, hydrogen has the advantages of clean products and high calorific value, and has received widespread attention in recent years. Traditional methods of hydrogen production mainly include natural gas hydrogen production, coal hydrogen production, water electrolysis hydrogen production, etc. However, the negative impact of traditional fossil fuel hydrogen production methods needs to be resolved. The alkaline water electrolysis hydrogen production process has a relatively mature hydrogen production technology, and the raw materials are simple and pollution-free. It is a powerful solution to cope with environmental changes. Today, the upper limit of the efficiency of hydrogen evolution in alkaline water electrolysis needs to be broken through. The reason is that the higher oxygen evolution reaction potential inhibits the evolution of hydrogen. Therefore, the development of a stable and efficient oxygen evolution catalyst is the key to increasing hydrogen production.

[0003] Previously, alkaline water electrolysis catalysts were mainly noble metal doping or spraying Raney nickel on a nickel base as an oxygen evolution electrode. The noble metals were limited in large-scale application due to their scarcity and high price. The catalytic layer prepared by the spraying method had problems such as unevenness and poor stability. In recent years, studies have found that transition metals such as Ni, Fe, and Co and their complexes have catalytic activity even higher than that of noble metals after appropriate modification. In particular, NiFe layered double hydroxide (NiFe-LDH) has excellent oxygen evolution reaction activity in electrode reactions. As an efficient oxygen evolution reaction (OER) catalyst, NiFe-LDH has a low overpotential and good catalytic activity and has a wide range of application prospects. Chinese patent CN117385396A discloses a method for preparing a nickel-iron layered double hydroxide material on the surface of nickel-iron foam, using a metal nickel-iron foam material as a substrate, using a Fenton reaction system to oxidatively corrode the nickel-iron substrate, and synthesizing a nickel-iron layered double hydroxide self-supporting electrode material on the nickel-iron foam substrate in a short time through a coprecipitation reaction, but the cost of the metal nickel-iron foam as a substrate is high.

[0004] Most of the electrode materials for water electrolysis and oxygen evolution on the market are nickel-based materials, including mesh and porous foam materials. According to the Shanghai Nonferrous Metals Market Data Survey in October 2024, the price of copper is 77,290 yuan / ton, while the price of metallic nickel is 131,900 to 134,700 yuan / ton, and the cost of nickel metal is about 1.7 times that of copper. Therefore, the production cost of alkaline water electrolysis catalysts based on nickel-based materials is relatively high.

[0005] Copper is one of the metal materials with good conductivity. It has small internal resistance and low energy loss under power-on conditions. However, due to the unstable chemical properties and low hardness of copper, the industrial application of Cu is seriously affected. In order to solve this problem, alloy materials formed by combining corrosion-resistant metals with Cu are widely used in the market, such as bronze, brass, and white copper. However, the introduction of other metals often affects the conductivity of Cu itself, which is not desirable for industries that require conductivity. Therefore, developing an electrode material with good conductivity and corrosion resistance as well as high catalytic activity is a key issue to be solved in the electrolysis of water reaction. Summary of the invention

[0006] The purpose of the present invention is to provide a nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material and its preparation method and application. The prepared composite material has excellent catalytic activity and stability, and has a low cost. The M@Cu substrate has good corrosion resistance and conductivity.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] On the one hand, the present invention provides a nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material, comprising a copper substrate, a metal functional layer M is arranged on the copper substrate, a NiFe-LDH active layer is arranged on the metal functional layer M, the NiFe-LDH active layer comprises nano-spherical NiFe-LDH, and the metal functional layer M comprises an anti-corrosion functional layer.

[0009] Preferably, the anti-corrosion functional layer is dense and has a thickness of 1 to 10 μm.

[0010] Preferably, the anti-corrosion functional layer includes any one of a Ni anti-corrosion functional layer, a NiSn anti-corrosion functional layer, and a Pt anti-corrosion functional layer.

[0011] In the present invention, the anti-corrosion functional layer is relatively thin and has good compactness, and can improve the corrosion resistance of the copper substrate.

[0012] Further preferably, the anti-corrosion functional layer is a Ni anti-corrosion functional layer, which is prepared by an electrodeposition method, and the specific steps are as follows: a double-electrode system is used, a pretreated copper substrate is used as a cathode, and a Ni-containing 100-300 g·L - 1 Ni 2 SO 4 6H 2 O, 10~30g·L -1 NiCl 2 6H 2 O, 10~30g·L -1 H 3BO 3 , 0.1~0.2g·L -1 Sodium dodecyl sulfate, 6-30 g·L -1 NaCl, 1~3g·L -1 Salicylic acid, 1-3 g·L -1 The aqueous solution of saccharin is the electrolyte, and the deposition current density is 2-4A·dm -2 , deposition time is 2 to 5 minutes, and electrolyte temperature is 25 to 60°C.

[0013] Further preferably, the anti-corrosion functional layer is a NiSn anti-corrosion functional layer, which is prepared by an electrodeposition method, and the specific steps are as follows: a double anode system is used, the pretreated copper substrate is used as the cathode, and a NiSn anti-corrosion functional layer containing 150-250 g·L - 1 K 4 P 2 O 7 15~25g·L -1 NiCl 2 6H 2 O, 0.05~0.2g·L -1 C 12 H 25 NaO 4 S, 15~25g·L- 1 NH 2 CH 2 COOH and 5~10g·L -1 SnCl 2 ·H 2 O aqueous solution is the electrolyte, the pH of the electrolyte is between 5 and 7, the temperature is 40°C to 65°C, and the deposition current density is 2 to 5A·dm -2 , time is 3 to 10 minutes.

[0014] More preferably, the dual anode system uses a nickel plate and a tin plate as anodes.

[0015] Further preferably, the anti-corrosion functional layer is a Pt anti-corrosion functional layer, which is prepared by cyclic voltammetry, and the specific steps are as follows: a three-electrode system is used, with a Hg / HgO electrode (saturated calomel electrode) as a reference electrode, a pretreated copper substrate as a working electrode, and a Pt electrode containing 0.5 to 1.5 g·L -1 H 2 PtCl 6 ·(H 2 O), 20~50g·L -1 KCl / NaCl / NH 4The aqueous solution of Cl is used as the electrolyte, the temperature of the electrolyte is room temperature, the scanning voltage of the cyclic voltammetry is -0.5 to 0.5 V, the CV cycle is 10 to 50 times, and the scanning rate is 20 to 100 mV·S -1 .

[0016] More preferably, the 20 to 50 g·L -1 KCl / NaCl / NH 4 The aqueous solution of Cl refers to 20~50g·L -1 Contains KCl or NaCl or NH 4 Aqueous solution of Cl.

[0017] In the present invention, the KCl or NaCl or NH 4 Cl acts as a conductive agent.

[0018] More preferably, in the three-electrode system, the Pt sheet is used as the counter electrode.

[0019] Further preferably, the copper substrate comprises a copper mesh.

[0020] Further preferably, the size of the copper mesh is (1-2) cm*(2-3) cm, and the mesh number is 180-220 meshes.

[0021] More preferably, the size of the copper mesh is 1*2 cm and the mesh number is 200 meshes.

[0022] Preferably, the pretreatment of the copper substrate includes pickling and degreasing, and pre-nickel plating.

[0023] Further preferably, the pickling and degreasing comprises the following steps: sealing the copper mesh (copper substrate) with glue at 1 cm, and cleaning it in 2-4 mol / L hydrochloric acid and anhydrous ethanol for 3-6 min each.

[0024] In the present invention, hydrochloric acid is used for pickling to remove the oxide layer on the surface of the copper substrate, and anhydrous ethanol is used to remove grease on the surface of the copper substrate.

[0025] Preferably, the pre-nickel plating comprises the following steps: using a copper mesh after pickling and degreasing as a cathode and a nickel rod as an anode, -1 Ni 2 SO 4 6H 2 O, 60~100ml·L -1 The acidic aqueous solution of HCl is a nickel plating solution, at 1~3A·dm -2 The nickel plating solution is deposited at a current density of 10 to 30 seconds, and the temperature of the nickel plating solution is 50 to 60°C.

[0026] More preferably, the pH of the nickel plating solution is 1.5-3.5.

[0027] In the present invention, pre-plating nickel on the surface of the copper substrate can further remove the oxide layer on the surface, and the deposited small amount of nickel can also improve the bonding strength between the plating layers.

[0028] Preferably, a catalytic structural layer is also provided on the anti-corrosion functional layer, and the thickness is 1 to 10 μm.

[0029] Preferably, the structure of the catalytic structural layer includes any one of holes, dendrites, and burrs, and the catalytic structural layer includes a Ni catalytic structural layer having a hole structure.

[0030] In the present invention, the catalytic structural layer can not only ensure that the copper substrate is not corroded, but also provide an active surface area for the catalyst.

[0031] Further preferably, the Ni catalytic structure layer with a porous structure is prepared by an electrodeposition method, and the specific steps are as follows: a double electrode system is used, a copper substrate containing an anti-corrosion functional layer is used as a cathode, and a Ni catalytic structure layer containing 10 to 50 g·L -1 NiCl 2 6H 2 O, 90~110g·L -1 NH 4 The aqueous solution of Cl is the electrolyte, the pH of the electrolyte is 2.5-4.5, the temperature is 25-60°C, and the deposition current density is 50-100A·dm -2 , time is 2 to 30 minutes.

[0032] In the present invention, the metal functional layer M plays a protective role on the surface of the copper substrate. The metal functional layer M increases the corrosion resistance of the copper substrate in alkaline solution, and can also increase the active sites for the catalyst, while also retaining the low resistance and high conductivity properties of copper itself to the greatest extent.

[0033] Preferably, the NiFe-LDH active layer is composed of nano-spherical NiFe-LDH.

[0034] Preferably, the nano-spherical NiFe-LDH is formed by stacking a plurality of sheet-like structures, and the diameter of the nano-sphere is 1 μm to 5 μm.

[0035] Preferably, the mass percentages of the elements in the NiFe-LDH are as follows: Ni 25-35%, Fe 35-50%, O 15-30%.

[0036] More preferably, the NiFe-LDH active layer has a thickness of 1 to 3 μm.

[0037] More preferably, in the NiFe-LDH, the ratio of Ni to Fe elements is 1:(1-1.2), and even more preferably 1:1.

[0038] Further preferably, the NiFe-LDH active layer is prepared by an electrodeposition method, and the specific steps are as follows: a double-electrode system is used, a copper substrate containing a metal functional layer M is used as a cathode, and a copper substrate containing 30 to 90 g·L -1 Provide Ni 2+ Nickel salts, 10-30 g·L -1 Provide Fe 2+ Iron salts, 1-2 g·L -1 Citric acid or citrate, 10-60 g·L -1 The aqueous solution of KCl or NaCl is the electrolyte, the electrolyte temperature is 24-28°C, and the deposition current density is 15-30A·dm -2 , the deposition time is 90s~120s.

[0039] More preferably, the nickel source (Ni 2+ ), iron source (Fe 2+ ) is in a molar ratio of (2-4):1, and more preferably 3:1.

[0040] More preferably, the electrolyte contains NiSO 4 6H 2 O(40~60g·L -1 ), FeSO 4 7H 2 O(15~20g·L -1 )、KCl(30~50g·L -1 ), anhydrous citric acid (1-2 g·L -1 ) in an aqueous solution.

[0041] Further preferably, when the NiFe-LDH active layer is prepared, the electrolyte needs to be activated first to ensure that there is a certain amount of Fe in the solution. 3+ ions, improving the preparation effect of NiFe-LDH active layer.

[0042] Further preferably, the activation comprises the following steps: using the pretreated copper substrate as the cathode and the platinum sheet as the anode, controlling the temperature of the electrolyte at 24-28°C, electro-depositing for 90s-120s, and the current density at 20A·dm -2 .

[0043] Further preferably, the NiFe-LDH active layer is prepared by steady-current deposition using a direct current power supply, and the current is slowly increased (slowly increased to 20 A within 30 s) to the deposition current density.

[0044] Further preferably, the method for preparing the nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material comprises the following steps:

[0045] S1. Copper substrate pretreatment: pickling and degreasing, pre-nickel plating;

[0046] S2, M@Cu preparation: Prepare different electrolytes for the metal functional layer M, use the copper substrate pretreated in S1 as the cathode, and deposit the metal functional layer M under constant current;

[0047] S3, preparation of NiFe-LDH@M@Cu: prepare a NiFe-LDH active layer electrolyte, use the M@Cu prepared in S2 as a cathode, deposit a NiFe-LDH active layer on the M@Cu under constant current, and prepare the NiFe-LDH@M@Cu.

[0048] In a second aspect, the present invention also provides an application of the nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material in oxygen evolution by alkaline water electrolysis.

[0049] The nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material of the present invention has good catalytic performance at room temperature and also has excellent stability under high temperature and concentrated alkali.

[0050] The present invention provides a nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material, wherein different metal functional layers are deposited on the surface of a copper substrate, including a dense anti-corrosion functional layer that can effectively improve the corrosion resistance of the substrate, such as a Ni anti-corrosion functional layer, a NiSn anti-corrosion functional layer, and a Pt anti-corrosion functional layer. A catalytic structural layer can be further arranged on the anti-corrosion functional layer to increase the surface active area of ​​the electrolytic water catalyst, such as a Ni catalytic structural layer. The different metal functional layers not only make up for the defects of the copper substrate, but also retain the excellent low resistance and high conductivity of the copper substrate itself. The NiFe-LDH catalyst is then combined to prepare the NiFe@M@Cu composite material, thereby achieving highly stable and high-performance oxygen evolution catalysis.

[0051] Among them, the copper substrate has good conductivity. As a substrate, it can provide a stable current transmission path to ensure that the NiFe-LDH catalytic active layer can efficiently carry out electrocatalytic hydrolysis reaction during the electrolysis process. And the copper substrate is cheaper than the nickel-based material. Using copper as a substrate can reduce the overall preparation cost. The nano-spherical NiFe-LDH prepared by deposition is composed of multiple sheet structures. Compared with other structures such as granular, coral-like, and nanowire-like, it has a larger active surface area, which is conducive to the mass transfer reaction between the electrolyte and the catalytic layer alkali, and is not easy to agglomerate. It has better stability, simple preparation, and short cycle.

[0052] Compared with the prior art, the present invention has the following beneficial effects:.

[0053] (1) The present invention prepares a nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material by sequentially depositing a metal functional layer M and a NiFe-LDH active layer on a copper substrate. The nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material has good stability and catalytic performance and low cost. At the same time, the prepared M@Cu has excellent corrosion resistance and conductivity.

[0054] (2) When the NiFe-LDH@M@Cu oxygen evolution composite material of the present invention is applied to alkaline water electrolysis, it has a small overpotential (200-209mV) and a low Tafel slope (38-41mV·dec) at room temperature. -1 ), larger active surface area (12.01-15.01mF·cm -2 ) and lower mass transfer resistance (0.148-0.258Ω), which greatly improves the catalytic effect.

[0055] (3) The NiFe-LDH@M@Cu oxygen evolution composite material of the present invention has excellent oxygen evolution reaction stability. The oxygen evolution reaction stability test is carried out under industrial conditions. In 30wt% KOH, 80°C electrolyte (i.e., high temperature concentrated alkali), when the voltage is 2V, the NiFe-LDH@Ni anti-corrosion functional layer@Cu oxygen evolution composite material can operate stably for more than 75 hours, which is significantly better than the performance of other NiFe-LDH catalysts.

[0056] (4) The M@Cu substrate prepared by the present invention has an impedance greater than 2005Ω, a corrosion voltage of 0-0.1V, and a corrosion current less than 8.785*10 -6 A, the corrosion rate is less than 0.575mm / year, it has good corrosion resistance, and can run stably for more than 85 hours at a voltage of 2V.

[0057] (5) The present invention improves various properties of the copper substrate by depositing different metal functional layers M on the copper substrate, and makes the substrate more corrosion-resistant by depositing an anti-corrosion functional layer. The catalytic structural layer with a specific structure can provide more structural sites and can better protect the Cu substrate. The metal functional layer M is relatively thin and will not affect the conductivity of the copper itself. Therefore, the M@Cu substrate of the present invention has good corrosion resistance while maintaining excellent conductivity and provides a stable current transmission path.

[0058] (6) The present invention protects the copper substrate by electroplating metal, and the entire process has the advantages of simple operation, easy control and short cycle.

[0059] (7) The copper substrate used in the present invention has low cost, good electrical conductivity and corrosion resistance, and is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is a gold image cross-sectional view of the Ni anti-corrosion functional layer@Cu of Example 1 of the present invention;

[0061] Figure 2 is an electron microscope photograph of the Ni anti-corrosion functional layer @Cu of Example 1 of the present invention;

[0062] Figure 3 is the XRD analysis diagram of the Ni anti-corrosion functional layer@Cu of Example 1 of the present invention;

[0063] Figure 4 This is an electron microscope photograph of the Ni catalytic structure layer @Ni anti-corrosion functional layer @Cu prepared in Example 3 of the present invention;

[0064] Figure 5 This is an electron microscope photograph of the NiFe-LDH@Ni anti-corrosion functional layer@Cu prepared in Example 2 of the present invention;

[0065] Figure 6 This is the energy dispersive analysis spectrum (EDS) of the NiFe-LDH@Ni anti-corrosion functional layer@Cu prepared in embodiment 2 of the present invention (A is a TEM image, B is a HRTEM image, C is an O element distribution, D is a Fe element distribution, and E is a Ni element distribution);

[0066] Figure 7 is an XRD spectrum of the NiFe-LDH@Ni anti-corrosion functional layer@Cu prepared in Example 2 of the present invention;

[0067] Figure 8 is an electron microscope photograph of the untreated copper mesh of Comparative Example 1 of the present invention;

[0068] Fig. 9 It is a dynamic polarization curve diagram of the materials of comparative examples 1-2 and example 1 of the present invention in 30wt% KOH at 80°C;

[0069] Fig.10 This is a stability test diagram of the untreated copper mesh of Comparative Example 1 of the present invention in 30 wt % KOH at 80° C.;

[0070] Fig.11 This is a stability test diagram of the Ni anti-corrosion functional layer@Cu prepared in Example 1 of the present invention in 30wt% KOH at 80°C;

[0071] Fig.12It is a comparison chart of LSV (a), Cdl (b), Tafer (c), and EIS (d) of the materials of Comparative Example 1 and Examples 1-4 of the present invention in 1M KOH at 25°C;

[0072] Fig.13 This is a stability test diagram of NiFe-LDH@Ni anti-corrosion functional layer@Cu prepared in Example 2 of the present invention in 30wt% KOH at 80°C;

[0073] Fig.14 This is the energy dispersive analysis spectrum (EDS) of the Ni anti-corrosion functional layer @Cu prepared in Example 1 of the present invention (A is a SEM image, B is Ni element distribution, and C is O element distribution);

[0074] Fig.15 It is a schematic diagram of the present invention. DETAILED DESCRIPTION

[0075] This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0076] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0077] A nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material, such as Fig.15 As shown, it includes a copper substrate, a metal functional layer M is arranged on the copper substrate, a NiFe-LDH active layer is arranged on the metal functional layer M, the NiFe-LDH active layer includes nano-spherical NiFe-LDH, the metal functional layer M includes an anti-corrosion functional layer, the anti-corrosion functional layer is dense, the thickness is 1 to 10 μm, and it includes any one of a Ni anti-corrosion functional layer, a NiSn anti-corrosion functional layer, and a Pt anti-corrosion functional layer. A catalytic structural layer is also arranged on the anti-corrosion functional layer, the thickness is 1 to 10 μm, the structure of the catalytic structural layer includes any one of holes, dendrites, and burrs, and the catalytic structural layer includes a Ni catalytic structural layer with a hole structure.

[0078] The composite material is obtained by the following preparation method:

[0079] S1. Copper substrate pretreatment: pickling and degreasing, pre-nickel plating;

[0080] S2, M@Cu preparation: Prepare different electrolytes for the metal functional layer M, use the copper substrate pretreated in S1 as the cathode, and deposit the metal functional layer M under constant current;

[0081] S3, preparation of NiFe-LDH@M@Cu: prepare a NiFe-LDH active layer electrolyte, use the M@Cu prepared in S2 as a cathode, deposit a NiFe-LDH active layer on the M@Cu under constant current, and prepare the NiFe-LDH@M@Cu.

[0082] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0083] Example 1

[0084] A Ni anti-corrosion functional layer@Cu substrate, the preparation method of which is as follows:

[0085] (1) Pretreatment of copper mesh: Cut the 200-mesh copper mesh into a 1cm*2cm rectangle and seal it with hot melt adhesive at 1cm. The upper half is where the electrode clamp is clamped, and the lower half is the catalytic effective area. The prepared copper mesh sample was cleaned in 3mol / L hydrochloric acid and anhydrous ethanol for 5min each, and then pre-plated with nickel. Constant current deposition was performed, with the anode being a nickel rod and the cathode being a Cu mesh after acid washing and degreasing, 2A·dm -2 The electrolyte is an acidic nickel plating solution containing 250 g·L - 1 Ni 2 SO 4 6H 2 O, 80ml·L -1 Aqueous solution of HCl, temperature 55°C.

[0086] (2) Preparation of Ni anti-corrosion functional layer @Cu substrate: Take the copper mesh pretreated in step (1), rinse it with deionized water, blow dry it with cold air, and quickly transfer it to the electrolyte. The cathode is the pretreated copper mesh and the anode is the nickel rod. The electrolyte composition contains Ni 2 SO 4 6H 2 O(250g·L -1 )、NiCl 2 6H 2 O(30g·L -1 ), H 3 BO 3 (30g·L -1 ), sodium dodecyl sulfate (0.12 g·L -1 )、NaCl(8g·L -1 ), salicylic acid (3 g·L -1 ), saccharin (3g·L -1 ) aqueous solution. At a deposition temperature of 55°C, 2A·dm -2The deposition current density was set at 200 °C for 2 minutes. After the deposition, the sample was taken out and thoroughly washed with deionized water. The sample was dried with cold air from a hair dryer and stored to obtain a Ni anti-corrosion functional layer @Cu substrate sample.

[0087] Example 2

[0088] A nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material, whose structure is NiFe-LDH@Ni anti-corrosion functional layer@Cu, and whose preparation method is as follows:

[0089] (1) Pretreatment of copper mesh: Cut the 200-mesh copper mesh into a 1cm*2cm rectangle and seal it with hot melt adhesive at 1cm. The upper half is where the electrode clamp is clamped, and the lower half is the catalytic effective area. The prepared copper mesh sample was cleaned in 3mol / L hydrochloric acid and anhydrous ethanol for 5min each, and then pre-plated with nickel. Constant current deposition was performed, with the anode being a nickel rod and the cathode being a Cu mesh after acid washing and degreasing, 2A·dm -2 The electrolyte is an acidic nickel plating solution containing 250 g·L - 1 Ni 2 SO 4 6H 2 O, 80ml·L -1 Aqueous solution of HCl, temperature 55°C.

[0090] (2) Activation electrolyte: Prepare NiFe-LDH active layer electrolyte, the electrolyte contains NiSO 4 6H 2 O50g·L -1 、FeSO 4 7H 2 O 18g·L -1 、KCl 40g·L -1 , anhydrous citric acid 1.3 g·L -1 aqueous solution; electrolyte activation: using a double electrode system at room temperature (25°C), taking the copper mesh pretreated in step 1 as the cathode and the platinum sheet as the anode, at 25°C with 20A·dm -2 The current density was 2000 nm and the electrodeposition was carried out for 90 s. After activation, the electrolyte was ultrasonicated to be uniform.

[0091] (3) Preparation of NiFe-LDH@Ni anti-corrosion functional layer@Cu: The Ni anti-corrosion functional layer@Cu substrate obtained in Example 1 was used as the cathode, and the platinum electrode was used as the anode. Steady flow deposition was adopted. The electrodeposition temperature was 25°C, the deposition time was 2 min, and the current density was 20 A·dm -2 , and the NiFe-LDH@Ni anti-corrosion functional layer@Cu was prepared.

[0092] Example 3

[0093] A Ni catalytic structural layer@Ni anti-corrosion functional layer@Cu substrate, the preparation method of which is as follows:

[0094] At room temperature (25°C), a double-electrode system was used, with the Ni anti-corrosion functional layer @Cu substrate in Example 1 as the cathode and the carbon rod as the anode. 2 6H 2 O 30g / L, NH 4 Cl 100g·L -1 , pH 3.5 aqueous solution as electrolyte, 100A·dm -2 The electrodeposition was carried out at a current density of 2 min. After the deposition, the sample was taken out and thoroughly washed with deionized water, dried with cold air from a hair dryer and stored to obtain a Ni catalytic structure layer @Ni anti-corrosion functional layer @Cu substrate sample.

[0095] Example 4

[0096] A nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material, whose structure is NiFe-LDH@Ni catalytic structural layer@Ni anti-corrosion functional layer@Cu, and whose preparation method is as follows:

[0097] (1) Pretreatment of copper mesh: Cut the 200-mesh copper mesh into a 1cm*2cm rectangle and seal it with hot melt adhesive at 1cm. The upper half is where the electrode clamp is clamped, and the lower half is the catalytic effective area. The prepared copper mesh sample was cleaned in 3mol / L hydrochloric acid and anhydrous ethanol for 5min each, and then pre-plated with nickel. Constant current deposition was performed, with the anode being a nickel rod and the cathode being a Cu mesh after acid washing and degreasing, 2A·dm -2 The electrolyte is an acidic nickel plating solution containing 250 g·L - 1 Ni 2 SO 4 6H 2 O, 80ml·L -1 Aqueous solution of HCl, temperature 55°C.

[0098] (2) Activation electrolyte: Prepare NiFe-LDH active layer electrolyte, the electrolyte contains NiSO 4 6H 2 O50g·L -1 、FeSO 4 7H 2 O 18g·L -1 、KCl 40g·L -1 , anhydrous citric acid 1.3 g·L -1aqueous solution; electrolyte activation: using a double electrode system at room temperature (25°C), taking the copper mesh pretreated in step 1 as the cathode and the platinum sheet as the anode, at 25°C with 20A·dm -2 The current density was 2000 nm and the electrodeposition was carried out for 90 s. After activation, the electrolyte was ultrasonicated to be uniform.

[0099] (3) Preparation of NiFe-LDH@Ni catalytic structure layer@Ni anti-corrosion functional layer@Cu: The Ni catalytic structure layer@Ni anti-corrosion functional layer@Cu substrate obtained in Example 3 was used as the cathode, and the platinum sheet electrode was used as the anode. Steady flow deposition was adopted. The electrodeposition temperature was 25°C, the deposition time was 2 min, and the current density was 20 A·dm -2 , NiFe-LDH@Ni catalytic structure layer@Ni anti-corrosion functional layer@Cu was prepared.

[0100] Example 5

[0101] A Pt anti-corrosion functional layer @Cu substrate, the preparation method of which is as follows:

[0102] (1) Pretreatment of copper mesh: Cut the 200-mesh copper mesh into a 1cm*2cm rectangle and seal it with hot melt adhesive at 1cm. The upper half is where the electrode clamp is clamped, and the lower half is the catalytic effective area. The prepared copper mesh sample was cleaned in 3mol / L hydrochloric acid and anhydrous ethanol for 5min each, and then pre-plated with nickel. Constant current deposition was performed, with the anode being a nickel rod and the cathode being a Cu mesh after acid washing and degreasing, 2A·dm -2 The electrolyte is an acidic nickel plating solution containing 250 g·L - 1 Ni 2 SO 4 6H 2 O, 80ml·L -1 Aqueous solution of HCl, temperature 55°C.

[0103] (2) Preparation of Pt anti-corrosion functional layer @Cu substrate: Take the pretreated copper mesh in step (1), rinse it with deionized water, blow dry it with cold air, and quickly transfer it to the electrolyte. The electrolyte contains 0.12g·L -1 H 2 PtCl 6 ·(H 2 O), 20g·L - 1 A three-electrode system was used, with the working electrode being the pretreated copper mesh, the Pt sheet being the counter electrode, and the reference being the Hg / HgO electrode. Cyclic voltammetry was used for deposition, with a voltage range of -0.5 to 0 V (vs. Hg / HgO) and a scan rate of 100 mV·S -1, CV cycle 20 times. After the end, take out the sample and wash it thoroughly with deionized water, blow dry with cold air from a hair dryer and store it.

[0104] Comparative Example 1

[0105] The material used in this comparative example is a copper mesh without any treatment.

[0106] Comparative Example 2

[0107] The material used in this comparative example is a nickel mesh without any treatment.

[0108] Figure 1 This is a metallographic cross-sectional view of the Ni anti-corrosion functional layer@Cu substrate of Example 1. The green coating in the figure is the Ni anti-corrosion functional layer with a thickness of 1 to 10 μm (the numerical dimensions in the figure are the thickness of the Ni anti-corrosion functional layer).

[0109] Figure 2 The SEM image of the Ni anti-corrosion functional layer @Cu substrate of Example 1 shows a dense particle layer. Fig.14 ) can prove that the coating is Ni.

[0110] Figure 3 This is the XRD analysis diagram of the Ni anti-corrosion functional layer @Cu substrate of Example 1. 43.31°, 50.44°, and 74.12° correspond to the Cu 111, 200, and 220 crystal planes (PDF#70-3039), and 44.27°, 51.53°, and 75.86° correspond to the Ni 111, 200, and 220 crystal planes (PDF#04-0850), indicating the presence of Ni.

[0111] Figure 4 This is the SEM image of the Ni catalytic structural layer@Ni anti-corrosion functional layer@Cu substrate of Example 3. Compared with the smooth Ni anti-corrosion functional layer, the Ni catalytic structural layer with more porous structures can provide abundant sites for the NiFe-LDH catalyst.

[0112] Figure 5 This is a SEM image of the NiFe-LDH active layer on the surface of the NiFe-LDH@Ni anti-corrosion functional layer@Cu prepared in Example 2. It can be seen from the figure that the size of the NiFe-LDH nanospheres is about 1μm-5μm. The nanospheres are assembled from flake NiFe-LDH and the elements are evenly distributed. The specific element distribution can be seen from Figure 6 The EDS diagram shows that the mass fraction of each element is shown in the following table:

[0113] Table 1 Total distribution of elements in NiFe-LDH nanospheres

[0114] element Line Type Wt% Wt%Sigma At% O K-line system 25.63 0.07 55.13 Fe K-line system 42.58 0.10 26.24 Ni K-line system 31.79 0.11 18.63

[0115] Figure 7 This is the XRD analysis diagram corresponding to Example 2. It can be observed that the peaks at 11.52°, 23.27°, 34.56°, 39.01°, 46.43°, 60.28°, 61.25°, and 65.23° point to the 003, 006, 012, 015, 018, 110, 113, and 116 crystal planes of NiFe LDH, respectively (PDF#51-0463). The lower peak is caused by the strong peak of the substrate. This shows that the NiFe-LDH@Ni anti-corrosion functional layer@Cu was successfully prepared.

[0116] Figure 8 This is a SEM image of the untreated copper mesh of Comparative Example 1. Through SEM observation, it can be seen that the surface of the copper mesh is smooth with irregular cracks.

[0117] The above materials are applied to the oxygen evolution reaction of water electrolysis under alkaline conditions, including the following test steps:

[0118] Step 1: Electrochemical testing was performed using a three-electrode system, with the working electrode being the prepared sample material, the reference electrode being a platinum sheet electrode, the counter electrode being a platinum wire electrode, and the electrolyte being a 80° C., 30 wt % KOH solution.

[0119] Step 2: Use impedance test (EIS) with a test frequency of 10 5 -10 -2 , amplitude 5mV.

[0120] Step 3: Use dynamic polarization curve test, voltage range -1 ~ 1V, scan rate 0.5mV / s, scan point interval 0.5mV.

[0121] Step 4: The sample material is the anode and the cathode is the Pt sheet. A voltage stabilization test is performed in an 80°C, 30wt% KOH electrolyte. The current change and test duration are recorded. The voltage is set to 2V.

[0122] The oxygen evolution catalytic performance of the above materials was evaluated and the process is briefly described as follows:

[0123] Step 1: Use a three-electrode system, with the anode being the test material, the counter electrode being a platinum sheet, the reference being a mercury / mercuric oxide electrode, and the electrolyte being 25°C, 1M KOH.

[0124] Step 2: Cyclic voltammetry (CV) was performed with a voltage range of 0-1 V, a scan rate of 100 mV / s, a scan interval of 5 mV, and a scan number of 20 circles to activate the catalyst.

[0125] Step 3: Linear voltammetry (LSV) with a scan rate of 5 mV / s and a scan interval of 1 mV / s to obtain the overpotentials (relative to RHE) at different current densities.

[0126] Step 4: Fit the linear voltammetric curve obtained in step 3 to obtain a Tafel curve, which reflects the kinetic properties of the catalyst.

[0127] Step 5: Select different scan rates (20mV / s, 40mV / s, 60mV / s, 80mV / s, 100mV / s) to perform CV cycles. By plotting the relationship between △j=(ja-jc) / 2 and the scan rate at the intermediate potential, the linear slope value can be obtained through linear fitting, and the double layer capacitance (Cdl) value can be obtained.

[0128] Step 6: Electrochemical impedance spectroscopy (EIS) test, with a frequency range of 0.1 to 105 Hz and an amplitude of 5 mV.

[0129] The dynamic polarization curves of Comparative Example 1, Comparative Example 2 and Example 1 were tested in 30 wt % KOH at 80° C. Fig. 9 As shown, the anti-corrosion performance related data are analyzed and compared as shown in Table 2. All data are obtained through Fig. 9 The polarization curve is extrapolated to show that compared with Cu, the presence of Ni anti-corrosion functional layer increases the corrosion voltage, reduces the corrosion current, and also slows down the corrosion rate. Compared with the commonly used nickel mesh in the market, it is found that the Cu mesh after plating with Ni anti-corrosion functional layer and the pure nickel mesh have similar anti-corrosion properties.

[0130] The stability test of Comparative Example 1 and Example 1 was carried out. Under the above electrolyte conditions (at 80°C, 30wt% KOH electrolyte), a voltage of 2V was applied, and Comparative Example 1 was completely dissolved within 4 hours ( Fig.10 ), the copper mesh with Ni anti-corrosion functional layer can be stable for ≥85H (such as Fig.11 ). It has been proven that the presence of the metal functional layer M can effectively increase the corrosion resistance of the copper substrate.

[0131] Table 2 Anticorrosion performance of comparative examples 1 to 2 and embodiment 1

[0132]

[0133]

[0134] At room temperature, Examples 1-4 and Comparative Example 1 were subjected to electrochemical tests in 1M KOH at 25°C, including CV, LSV, and EIS analysis, and the overpotential, Tafel slope (Tafei), double layer capacitance (Cdl), and impedance (EIS) ( Fig.12 ), and the performance data are summarized in Table 3 below.

[0135] The data show that the Ni anti-corrosion functional layer @Cu has no superior catalytic performance. The larger mass transfer resistance (6553Ω) means better corrosion resistance. On this basis, a NiFe-LDH activation layer is deposited on the NiFe-LDH@Ni anti-corrosion functional layer @Cu, which has a low overpotential (209mV) and a larger active surface area (≥15.01mF·cm -2 ) and low charge transfer resistance (less than 0.258Ω), indicating that it has good catalytic performance. The NiFe-LDH@Ni anti-corrosion functional layer@Cu was applied to industrial conditions (80℃30wt%KOH) for stability testing and found that it can stably exist for 75H( Fig.13 ), which is much higher than other non-precious metal catalysts. Due to the presence of the Ni catalytic structure layer, Example 4 has a lower overpotential (200mV) and charge transfer internal resistance (0.148Ω) than Example 2, indicating that its catalytic performance has been further improved.

[0136] Table 3 Electrochemical performance of Example 1 and Example 2

[0137] Material Overvoltage (mV) <![CDATA[Tafel (mV·dec -1 )]]> <![CDATA[Double electric layer (mF·cm -2 )]]> Impedance(Ω) Example 1 327 64.60 0.385 6553 Example 2 209 38.99 15.01 0.258 Example 3 346 79.30 9.30 111 Example 4 200 41.00 12.01 0.148

[0138] In summary, the present invention prepares a nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material by sequentially depositing a metal functional layer and a NiFe-LDH active layer on a copper substrate. The nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material has good corrosion resistance, stability, and catalytic performance, and has low cost, and is suitable for large-scale application under industrial conditions.

[0139] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material, characterized in that: It comprises a copper substrate, a metal functional layer M is arranged on the copper substrate, a NiFe-LDH active layer is arranged on the metal functional layer M, the NiFe-LDH active layer comprises nano-spherical NiFe-LDH, and the metal functional layer M comprises an anti-corrosion functional layer.

2. The nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material according to claim 1, characterized in that: The anti-corrosion functional layer is dense and has a thickness of 1 to 10 μm. The anti-corrosion functional layer includes any one of a Ni anti-corrosion functional layer, a NiSn anti-corrosion functional layer, and a Pt anti-corrosion functional layer.

3. A nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material according to claim 2, characterized in that: The anti-corrosion functional layer is a Ni anti-corrosion functional layer, which is prepared by an electrodeposition method. The specific steps are as follows: a double-electrode system is used, a pretreated copper substrate is used as a cathode, and a Ni-containing 100-300 g·L -1 Ni2SO4·6H2O, 10~30g·L -1 NiCl2·6H2O, 10~30g·L -1 H3BO3, 0.1~0.2g·L -1 Sodium dodecyl sulfate, 6-30 g·L -1 NaCl, 1~3g·L -1 Salicylic acid, 1-3 g·L -1 The aqueous solution of saccharin is the electrolyte, and the deposition current density is 2-4A·dm -2 , deposition time is 2 to 5 minutes, and electrolyte temperature is 25 to 60°C.

4. The nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material according to claim 2, characterized in that: The anti-corrosion functional layer is a NiSn anti-corrosion functional layer, which is prepared by an electrodeposition method. The specific steps are as follows: a double anode system is used, a pretreated copper substrate is used as a cathode, and a NiSn layer containing 150 to 250 g·L -1 K4P2O7, 15~25g·L -1 NiCl2·6H2O, 0.05~0.2g·L -1 C 12 H 25 NaO4S, 15~25g·L- 1 NH2CH2COOH and 5~10g·L -1 The aqueous solution of SnCl2·H2O is the electrolyte, the pH of the electrolyte is between 5 and 7, the temperature is 40°C to 65°C, and the deposition current density is 2 to 5A·dm -2 , time is 3 to 10 minutes.

5. The nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material according to claim 2, characterized in that: The anti-corrosion functional layer is a Pt anti-corrosion functional layer, which is prepared by cyclic voltammetry. The specific steps are as follows: a three-electrode system is used, a Hg / HgO electrode is used as a reference electrode, a pretreated copper substrate is used as a working electrode, and a Pt anti-corrosion functional layer is prepared by cyclic voltammetry. - 1 H2PtCl6·(H2O), 20~50g·L -1 The aqueous solution of KCl / NaCl / NH4Cl is the electrolyte, the temperature of the electrolyte is room temperature, the scanning voltage of the cyclic voltammetry is -0.5 to 0.5 V, the CV cycle is 10 to 50 cycles, and the scanning rate is 20 to 100 mV·S -1 .

6. The nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material according to claim 1, characterized in that: A catalytic structural layer is also provided on the anti-corrosion functional layer, with a thickness of 1 to 10 μm. The structure of the catalytic structural layer includes any one of holes, dendrites, and burrs. The catalytic structural layer includes a Ni catalytic structural layer with a hole structure.

7. The nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material according to claim 6, characterized in that: The Ni catalytic structure layer with a porous structure is prepared by an electrodeposition method, and the specific steps are as follows: a double-electrode system is used, a copper substrate containing an anti-corrosion functional layer is used as a cathode, and a Ni catalytic structure layer containing 10 to 50 g·L -1 NiCl2·6H2O, 90~110g·L -1 The aqueous solution of NH4Cl is the electrolyte, the pH of the electrolyte is 2.5-4.5, the temperature is 25-60°C, and the deposition current density is 50-100A·dm -2 , time is 2 to 30 minutes.

8. The nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material according to claim 1, characterized in that: The nano-spherical NiFe-LDH is formed by stacking a plurality of sheet structures, the diameter of the nano-sphere is 1 μm to 5 μm, and the mass percentage of each element in the NiFe-LDH is as follows: Ni 25 to 35%, Fe 35 to 50%, and O 15 to 30%.

9. The nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material according to claim 1, characterized in that: The NiFe-LDH active layer is prepared by an electrodeposition method, and the specific steps are as follows: a double-electrode system is used, a copper substrate containing a metal functional layer M is used as a cathode, and a copper substrate containing 30 to 90 g·L -1 Provide Ni 2+ Nickel salts, 10-30 g·L -1 Provide Fe 2+ Iron salts, 1-2 g·L -1 Citric acid or citrate, 10-60 g·L -1 The aqueous solution of KCl or NaCl is the electrolyte, the temperature of the electrolyte is 24-28°C, and the deposition current density is 15-30A·dm -2 , the deposition time is 90s~120s.

10. Use of the nano-spherical NiFe-LDH@M@Cu oxygen evolution composite material as claimed in any one of claims 1 to 9 in oxygen evolution by alkaline water electrolysis.

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