Preparation method of titanium-based anti-scaling cathode with water electrolysis catalysis function

Abstract

The invention belongs to the technical field of electrodes, and discloses a preparation method of a titanium-based anti-scaling cathode with an electrolyzed water catalysis function, which comprises the following steps: constructing a microstructure on the surface of a titanium mesh substrate; a transition metal catalyst is loaded on the microstructure; the surface of the microstructure material with the catalytic function is coated with an inert coating. The inert coating on the surface of the cathode can prevent electrons from being in contact with water molecules, so that only the tip of the microstructure which is not covered by the inert coating serves as an initial nucleation site of the crystal. When the crystal grows to a micron order, the adhesive force between the crystal and the tip of the microstructure is weakened. Meanwhile, bubbles generated by electrolyzing water can grow along the inert coating and crack near the tip of the microstructure to push the crystals to fall off spontaneously, so that the crystals are prevented from being deposited and accumulated on the surface of an electrode. And meanwhile, metal cations such as Ni < 2 + > and Co < 2 + > loaded on the microstructure can reduce the overpotential of electrolyzed seawater. Due to the two properties, the cathode can be applied to extraction of magnesium resources in seawater.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrodes and relates to a preparation method of a titanium-based anti-fouling cathode with water electrolysis catalysis function. BACKGROUND

[0002] Electrochemical technology provides a promising way for the sustainable exploitation of valuable resources (such as high-purity magnesium hydroxide) from seawater. However, the practical application of electrochemical technology is severely hindered by two core challenges: first, the insufficient catalytic activity of electrode materials leads to excessively high energy consumption for seawater electrolysis. The theoretical overpotential of water electrolysis is 0 V (vs. RHE), but in actual seawater electrolysis, for example, the overpotential of the commonly used iron electrode is about 0.5-0.8 V (vs. RHE) at a current density of 10 mA / cm 2 , which is much higher than the theoretical value; second, during the electrolysis process, the OH - concentration near the cathode surface increases due to the reaction of HCO3 - , Ca 2+ , and Mg 2+ in water, which produces insulating CaCO3 and Mg(OH)2, and eventually precipitates on the cathode surface and gradually accumulates to form a hard deposition layer, resulting in a reduction in the effective working area of the electrode and ultimately terminating the reaction. Therefore, the problems of electrode fouling and high energy consumption are hindering the practical application of electrochemical technology in the recovery of magnesium resources from seawater.

[0003] In recent years, various solutions have been proposed to address the problems of cathode fouling and high overpotential during seawater electrolysis. For example, the reference Solidophobic surface for electrochemical extraction of high-valued Mg(OH)2 coupled with H2 production from seawater constructs a high-surface-energy nickel-copper alloy electrode that repels magnesium ion deposition by adsorbing a water layer, achieving stable operation for 1000 hours in a solution with 10 times the magnesium concentration of natural seawater, but the hydrogen evolution overpotential of the electrode is still relatively high; the reference Self-limited formation of nanoporous nickel heterostructure catalyst for electrochemical hydrogen production develops a nanoporous Ni / NiO electrode that reduces the overpotential of water electrolysis through interface synergistic catalysis, but its surface is easily covered with magnesium hydroxide, which requires regular mechanical cleaning to maintain efficiency, significantly increasing operation and maintenance costs. In summary, a single strategy often cannot balance energy consumption and anti-fouling performance, which has become a technical bottleneck for the extraction of high-purity magnesium hydroxide from seawater by electrolysis.

[0004] Obviously, to completely solve this problem, it is necessary to develop a kind of anti-fouling cathode with water electrolysis catalytic function. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of titanium-based anti-fouling cathode with water electrolysis catalytic function.

[0006] The technical scheme of the present application:

[0007] A preparation method of titanium-based anti-fouling cathode with water electrolysis catalytic function, the steps are as follows:

[0008] (1) Preparation of cathode with surface microstructure: pretreat the titanium mesh, then put the dried titanium mesh into a stainless steel reaction kettle lined with polytetrafluoroethylene, add 1 M strong alkali aqueous solution, and immerse the titanium mesh in the strong alkali aqueous solution; seal the stainless steel reaction kettle, heat at 180-220 ℃ for 3-4 hours, then naturally cool to room temperature, and obtain an electrode with surface microstructure;

[0009] (2) Preparation of cathode with water electrolysis catalytic function microstructure: immerse the electrode with surface microstructure in 1 M metal nitrate solution at a constant temperature of 50-70 ℃ for ion exchange for 20-24 hours, and obtain an electrode with water electrolysis catalytic function microstructure;

[0010] (3) Construction of inert coating: prepare an inert coating containing inert reagents, dispersants and binders, immerse the electrode with water electrolysis catalytic function microstructure in the inert coating for 10-30 min, and heat cure the immersed electrode in an inert atmosphere at a temperature of 50-450 ℃ for 300 min to obtain a titanium-based anti-fouling cathode with water electrolysis catalytic function.

[0011] In step (1), the morphology of the surface microstructure includes but is not limited to conical, flower-shaped, flaky, etc.

[0012] In step (1), the strong alkali aqueous solution includes but is not limited to one or more than two kinds of mixture of sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, etc.

[0013] In step (2), the metal nitrate includes but is not limited to one or more than two kinds of mixture of nickel nitrate, cobalt nitrate, potassium nitrate, iron nitrate, cerium nitrate, lead nitrate, calcium nitrate, etc.

[0014] In step (3), the mass ratio of inert reagents, dispersants and binders is 0.5-50:0.01-10:0.1-50.

[0015] In step (3), the inert agent includes one or more than two kinds of mixture selected from the group consisting of polytetrafluoroethylene, dodecanethiol, perfluorodecyltrimethoxysilane, and the like. The dispersing agent includes one or more than two kinds of mixture selected from the group consisting of xanthan gum, anhydrous ethanol, ultrapure water, and the like. The binder includes one or more than two kinds of mixture selected from the group consisting of epoxy resin, polydimethylsiloxane, acrylic resin, and the like.

[0016] The present application has the following advantages: The present application constructs a preparation method of titanium-based anti-fouling cathode with water electrolysis catalytic function. Firstly, the water hydrothermal in-situ etching growth technology is used to replace the traditional electrodeposition technology to prepare the microstructure on the surface of the cathode. This technology overcomes the "edge effect" and "shielding effect" caused by uneven charge distribution on the three-dimensional titanium mesh substrate, and realizes the 360° uniform coverage of the micro-cone structure on the complex titanium mesh surface. More importantly, the microstructure generated by the water hydrothermal method has a chemical bonding in-situ growth relationship with the substrate, and the bonding force is much stronger than that of the physical adhesion of the electrodeposited layer, effectively solving the problem of coating peeling caused by bubble impact under high current conditions. In addition, the titanate framework formed by the water hydrothermal method has a unique layered ion exchange property, which provides a necessary chemical structure basis for the subsequent introduction of metal cations (such as Ni 2+ , Co 2+ , etc.) by ion exchange method, which is not achieved by the dense electrodeposited layer. Secondly, the high-activity metal cations (such as Ni 2+ , Co 2+ , etc.) are introduced by in-situ doping strategy, which significantly reduces the overpotential of water electrolysis, and solves the problem of high energy consumption caused by surface passivation or coating coverage of the traditional anti-fouling electrode. Finally, the present application innovatively constructs a "inert coating-active tip" discontinuous interface, while the existing anti-fouling electrode mostly uses a "completely hydrophobic coating", which sacrifices the catalytic activity of the electrode. By controlling the coating parameters, the present application makes the inert coating only fill in the gap between the microstructures, blocking the electron transmission; while the uncoated microstructure tips act as active sites and initial nucleation sites for crystals (such as Mg(OH)2). Since the hydrogen bubbles generated by electrolysis are mainly generated at the tips, the mechanical shear force generated by the bubbles during growth and rupture will cause the micron-sized crystals (1~3 μm) attached to the tips to spontaneously fall off, without the need for external intervention to avoid sediment accumulation. The present application is expected to solve the trade-off problem between anti-fouling performance and energy efficiency in the practical application of electrochemical technology, without the need for dosing, additional operation steps, or interruption of the electrochemical reaction, with the advantages of low carbon, simplicity, and high efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a physical map of a titanium-based anti-fouling electrode with water electrolysis catalytic function.

[0018] Figure 2is a scanning electron microscope image of a titanium-based anti-fouling electrode with water electrolysis catalytic function.

[0019] Figure 3 is a scanning electron microscope image of the microstructure of the titanium mesh surface constructed by electrodeposition.

[0020] Figure 4 is a scanning electron microscope image of the microstructure electrode after 4 h of hydrothermal treatment.

[0021] Figure 5 is a scanning electron microscope image of the microstructure electrode after 150℃ hydrothermal treatment.

[0022] Figure 6 is a scanning electron microscope image of the microstructure electrode with water electrolysis catalytic function after 30 h of immersion in a nickel nitrate solution.

[0023] Figure 7 is a scanning electron microscope image of a titanium-based anti-fouling electrode with water electrolysis catalytic function obtained after adjusting the proportions of inert reagents, dispersants and binders.

[0024] Figure 8 is a scanning electron microscope image of a titanium-based anti-fouling electrode with water electrolysis catalytic function obtained after extending the immersion time of the inert coating.

[0025] Figure 9 is a voltammogram of the electrodes with a metal nitrate concentration of 0.5 M and 1 M.

[0026] Figure 10 is a scanning electron microscope image of the electrode in which the inert coating lacks a dispersant.

[0027] Figure 11 is a physical image of magnesium hydroxide recovered from seawater using a titanium-based anti-fouling electrode with water electrolysis catalytic function.

[0028] Figure 12 is a voltage-time curve of a titanium-based anti-fouling electrode with water electrolysis catalytic function and a titanium mesh electrode in seawater at a current density of 100 mA / cm -2 for 100 h.

[0029] Figure 13 is a before-and-after physical image of the electrode after 100 h of reaction in seawater of an electrode with water electrolysis catalytic function, in which (a) is a titanium mesh electrode and (b) is an anti-fouling electrode. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application are further illustrated in the following description with reference to the accompanying drawings and technical solutions.

[0031] Example 1

[0032] (1) 40 mesh commercial titanium mesh was used as the substrate. All solutions in the experiment were prepared with analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh was first cleaned to remove surface contaminants and oxides. The dried titanium mesh was placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor was filled with 30 mL of NaOH aqueous solution (1 M). The sealed high-pressure reactor was stored in an oven preheated to 220°C for 3 h, and then naturally cooled to room temperature. The titanium mesh after hydrothermal reaction was washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0033] (2) The electrode with surface microstructure was immersed in a 1 M Ni(NO3)2 solution at a constant temperature of 50°C for 20 h. The cathode after immersion treatment was taken out and dried to obtain a microstructured electrode with water electrolysis catalytic function.

[0034] (3) An inert coating with a mass fraction ratio of ultrapure water, dodecanethiol, and acrylic resin of 50:10:0.1 was prepared. The microstructured electrode with water electrolysis catalytic function obtained in step (2) was immersed in the prepared inert coating for 10 min, and then taken out and heat cured at a temperature of 450°C for 300 min to obtain a titanium-based anti-fouling cathode with water electrolysis catalytic function. The actual object is shown in Figure 1 , and the electrode surface micro-morphology is shown in Figure 2 .

[0035] Example 2

[0036] (1) 40 mesh commercial titanium mesh was used as the substrate. All solutions in the experiment were prepared with analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh was first cleaned to remove surface contaminants and oxides. The dried titanium mesh was placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor was filled with 30 mL of NaOH aqueous solution (1 M). The sealed high-pressure reactor was stored in an oven preheated to 220°C for 3 h, and then naturally cooled to room temperature. The titanium mesh after hydrothermal reaction was washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0037] (2) The electrode with surface microstructure was immersed in a 1 M Ni(NO3)2 solution at a constant temperature of 50°C for 20 h. The cathode after immersion treatment was taken out and dried to obtain a microstructured electrode with water electrolysis catalytic function.

[0038] (3) An inert coating with a mass fraction ratio of ultrapure water, dodecanethiol, and acrylic resin of 50:10:0.1 was prepared. The microstructured electrode with water electrolysis catalytic function obtained in step (2) was immersed in the prepared inert coating for 10 min, and then taken out and heat cured at a temperature of 450°C for 300 min to obtain a titanium-based anti-fouling cathode with water electrolysis catalytic function.

[0039] Example 3

[0040] (1) A 40 mesh commercial titanium mesh was used as the substrate. All solutions in the experiment were prepared with analytical grade chemicals and ultrapure water. Before the hydrothermal treatment, the titanium mesh was first cleaned to remove the surface contaminants and oxides. The dried titanium mesh was placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, which was filled with 30 mL of NaOH aqueous solution (1 M). The sealed high-pressure reactor was kept in an oven preheated to 220 °C for 4 h and naturally cooled to room temperature. The titanium mesh after the hydrothermal reaction was rinsed with ultrapure water several times to obtain an electrode with surface microstructure.

[0041] (2) The electrode with surface microstructure was immersed in 1 M Ni(NO3)2solution at a constant temperature of 50 °C for 20 h. The cathode after the immersion treatment was taken out and dried to obtain a microstructured cathode with water electrolysis catalytic performance.

[0042] (3) An inert coating with a mass fraction ratio of ultrapure water, dodecanethiol, and acrylic resin of 50:10:0.1 was prepared. The microstructured electrode with water electrolysis catalytic function obtained in step (2) was immersed in the prepared inert coating for 10 min, and after taking out, it was heat cured at a temperature of 450 °C for 300 min to obtain a titanium-based anti-fouling cathode with water electrolysis catalytic function.

[0043] Example 4

[0044] (1) A 40 mesh commercial titanium mesh was used as the substrate. All solutions in the experiment were prepared with analytical grade chemicals and ultrapure water. Before the hydrothermal treatment, the titanium mesh was first cleaned to remove the surface contaminants and oxides. The dried titanium mesh was placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, which was filled with 30 mL of NaOH aqueous solution (1 M). The sealed high-pressure reactor was kept in an oven preheated to 180 °C for 3 h and naturally cooled to room temperature. The titanium mesh after the hydrothermal reaction was rinsed with ultrapure water several times to obtain an electrode with surface microstructure.

[0045] (2) The electrode with surface microstructure was immersed in 1 M Ni(NO3)2solution at a constant temperature of 50 °C for 20 h. The cathode after the immersion treatment was taken out and dried to obtain a microstructured electrode with water electrolysis catalytic function.

[0046] (3) The inert coating with a mass fraction ratio of ultrapure water, dodecanethiol, and acrylic resin of 50:10:0.1 is prepared, the microstructured electrode with water electrolysis catalysis function obtained in step (2) is immersed in the prepared inert coating for 10 min, and after being taken out, it is heat cured at a temperature of 450°C for 300 min to obtain a titanium-based anti-fouling cathode with water electrolysis catalysis function.

[0047] Example 5

[0048] (1) A 40-mesh commercial titanium mesh is used as a substrate. All solutions in the experiment are prepared using analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh is first cleaned to remove surface contaminants and oxides. The dried titanium mesh is placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor is filled with 30 mL of NaOH aqueous solution (1M). The sealed high-pressure reactor is stored in an oven preheated to 220°C for 3 h, and naturally cooled to room temperature. The titanium mesh after hydrothermal reaction is washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0049] (2) The electrode with surface microstructure is immersed in a 1 M Co(NO3)2 solution at a constant temperature of 50°C for 20 h, and the immersed cathode is taken out and dried to obtain a microstructured electrode with water electrolysis catalysis function.

[0050] (3) The inert coating with a mass fraction ratio of ultrapure water, dodecanethiol, and acrylic resin of 50:10:0.1 is prepared, the microstructured electrode with water electrolysis catalysis function obtained in step (2) is immersed in the prepared inert coating for 10 min, and after being taken out, it is heat cured at a temperature of 450°C for 300 min to obtain a titanium-based anti-fouling cathode with water electrolysis catalysis function.

[0051] Example 6

[0052] (1) A 40-mesh commercial titanium mesh is used as a substrate. All solutions in the experiment are prepared using analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh is first cleaned to remove surface contaminants and oxides. The dried titanium mesh is placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor is filled with 30 mL of NaOH aqueous solution (1M). The sealed high-pressure reactor is stored in an oven preheated to 220°C for 3 h, and naturally cooled to room temperature. The titanium mesh after hydrothermal reaction is washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0053] (2) The electrode with surface microstructure is immersed in a 1 M Ni(NO3)2 solution at a constant temperature of 70°C for 20 h, and the immersed cathode is taken out and dried to obtain a microstructured electrode with water electrolysis catalysis function.

[0054] (3) Prepare an inert coating with a mass fraction ratio of ultrapure water, dodecanethiol, and acrylic resin of 50:10:0.1. Immerse the microstructured electrode with water electrolysis catalysis function obtained in step (2) in the prepared inert coating for 10 min. After taking out, heat cure at a temperature of 450°C for 300 min to obtain a titanium-based anti-fouling cathode with water electrolysis catalysis function.

[0055] Example 7

[0056] (1) A 40-mesh commercial titanium mesh was used as the substrate. All solutions in the experiment were prepared using analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh was first cleaned to remove surface contaminants and oxides. The dried titanium mesh was placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor was filled with 30 mL of NaOH aqueous solution (1M). The sealed high-pressure reactor was stored in an oven preheated to 220°C for 3 h and naturally cooled to room temperature. The titanium mesh after hydrothermal reaction was washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0057] (2) The electrode with surface microstructure was immersed in a 1 M Ni(NO3)2 solution at a constant temperature of 50°C for 24 h. The immersed cathode was taken out and dried to obtain a microstructured electrode with water electrolysis catalysis function.

[0058] (3) An inert coating with a mass fraction ratio of ultrapure water, dodecanethiol, and acrylic resin of 50:10:0.1 was prepared. The microstructured electrode with water electrolysis catalysis function obtained in step (2) was immersed in the prepared inert coating for 10 min. After taking out, heat cure at a temperature of 450°C for 300 min to obtain a titanium-based anti-fouling cathode with water electrolysis catalysis function.

[0059] Example 8

[0060] (1) A 40-mesh commercial titanium mesh was used as the substrate. All solutions in the experiment were prepared using analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh was first cleaned to remove surface contaminants and oxides. The dried titanium mesh was placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor was filled with 30 mL of NaOH aqueous solution (1M). The sealed high-pressure reactor was stored in an oven preheated to 220°C for 3 h and naturally cooled to room temperature. The titanium mesh after hydrothermal reaction was washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0061] (2) The electrode with surface microstructure was immersed in a 1 M Ni(NO3)2 solution at a constant temperature of 50°C for 20 h. The immersed cathode was taken out and dried to obtain a microstructured electrode with water electrolysis catalysis function.

[0062] (3) Prepare an inert coating of ultrapure water, polytetrafluoroethylene, and acrylic resin in a mass fraction ratio of 50:10:0.1. Immerse the microstructured electrode with water electrolysis catalytic function obtained in step (2) in the prepared inert coating for 10 min. After taking out, heat cure at a temperature of 450 °C for 300 min to obtain a titanium-based anti-fouling cathode with water electrolysis catalytic function.

[0063] Example 9

[0064] (1) A 40-mesh commercial titanium mesh was used as the substrate. All solutions in the experiment were prepared using analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh was first cleaned to remove surface contaminants and oxides. The dried titanium mesh was placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor was filled with 30 mL of NaOH aqueous solution (1M). The sealed high-pressure reactor was stored in a preheated oven at 220°C for 3 h and naturally cooled to room temperature. The titanium mesh after hydrothermal reaction was washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0065] (2) The electrode with surface microstructure was immersed in a 1 M Ni(NO3)2 solution at a constant temperature of 50°C for 20 h. The immersed cathode was taken out and dried to obtain a microstructured electrode with water electrolysis catalytic function.

[0066] (3) Prepare an inert coating of ultrapure water, dodecanethiol, and epoxy resin in a mass fraction ratio of 50:10:0.1. Immerse the microstructured electrode with water electrolysis catalytic function obtained in step (2) in the prepared inert coating for 10 min. After taking out, heat cure at a temperature of 450 °C for 300 min to obtain a titanium-based anti-fouling cathode with water electrolysis catalytic function.

[0067] Example 10

[0068] (1) A 40-mesh commercial titanium mesh was used as the substrate. All solutions in the experiment were prepared using analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh was first cleaned to remove surface contaminants and oxides. The dried titanium mesh was placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor was filled with 30 mL of NaOH aqueous solution (1M). The sealed high-pressure reactor was stored in a preheated oven at 220°C for 3 h and naturally cooled to room temperature. The titanium mesh after hydrothermal reaction was washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0069] (2) The electrode with surface microstructure is immersed in 1 M Ni(NO3)2 solution at a constant temperature of 50°C for 20 h, and the immersed cathode is taken out and dried to obtain the microstructured electrode with water electrolysis catalytic function.

[0070] (3) An inert coating with a mass fraction ratio of anhydrous ethanol, dodecanethiol, and acrylic resin of 50:10:0.1 is prepared, the microstructured electrode with water electrolysis catalytic function obtained in step (2) is immersed in the prepared inert coating for 10 min, and after being taken out, it is heat cured at a temperature of 450°C for 300 min to obtain the titanium-based anti-fouling cathode with water electrolysis catalytic function.

[0071] Example 11

[0072] (1) A 40-mesh commercial titanium mesh is used as a substrate. All solutions in the experiment are prepared using analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh is first cleaned to remove surface contaminants and oxides. The dried titanium mesh is placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor is filled with 30 mL of NaOH aqueous solution (1M). The sealed high-pressure reactor is stored in a preheated oven at 220°C for 3 h and naturally cooled to room temperature. The titanium mesh after hydrothermal reaction is washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0073] (2) The electrode with surface microstructure is immersed in 1 M Ni(NO3)2 solution at a constant temperature of 50°C for 20 h, and the immersed cathode is taken out and dried to obtain the microstructured electrode with water electrolysis catalytic function.

[0074] (3) An inert coating with a mass fraction ratio of ultrapure water, dodecanethiol, and acrylic resin of 50:10:0.1 is prepared, the microstructured electrode with water electrolysis catalytic function obtained in step (2) is immersed in the prepared inert coating for 30 min, and after being taken out, it is heat cured at a temperature of 450°C for 300 min to obtain the titanium-based anti-fouling cathode with water electrolysis catalytic function.

[0075] Example 12

[0076] (1) A 40-mesh commercial titanium mesh is used as a substrate. All solutions in the experiment are prepared using analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh is first cleaned to remove surface contaminants and oxides. The dried titanium mesh is placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor is filled with 30 mL of NaOH aqueous solution (1M). The sealed high-pressure reactor is stored in a preheated oven at 220°C for 3 h and naturally cooled to room temperature. The titanium mesh after hydrothermal reaction is washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0077] (2) The electrode with surface microstructure was immersed in 1 M Ni(NO3)2 solution at a constant temperature of 50 °C for 20 h. The cathode after immersion treatment was taken out and dried to obtain a microstructure electrode with water electrolysis catalytic function.

[0078] (3) An inert coating with a mass fraction ratio of ultrapure water, dodecanethiol and acrylic resin of 50:10:0.1 was prepared. The microstructure electrode with water electrolysis catalytic function obtained in step (2) was immersed in the prepared inert coating for 10 min. After taking out, it was heat cured at a temperature of 50 °C for 300 min to obtain a titanium-based anti-fouling electrode with water electrolysis catalytic performance.

[0079] Example 13

[0080] (1) A 40 mesh commercial titanium mesh was used as the substrate. All solutions in the experiment were prepared with analytical grade chemicals and ultrapure water. Before hydrothermal treatment, the titanium mesh was first cleaned to remove surface contaminants and oxides. The dried titanium mesh was placed on the inner wall of a 50 mL Teflon-lined stainless steel high-pressure reactor, and the high-pressure reactor was filled with 30 mL of NaOH aqueous solution (1 M). The sealed high-pressure reactor was stored in a preheated oven at 220 °C for 3 h and naturally cooled to room temperature. The titanium mesh after hydrothermal reaction was washed with ultrapure water several times to obtain an electrode with surface microstructure.

[0081] (2) The electrode with surface microstructure was immersed in 1 M Ni(NO3)2 solution at a constant temperature of 50 °C for 20 h. The cathode after immersion treatment was taken out and dried to obtain a microstructure electrode with water electrolysis catalytic function.

[0082] (3) An inert coating with a mass fraction ratio of ultrapure water, dodecanethiol and acrylic resin of 0.5:0.01:50 was prepared. The microstructure electrode with water electrolysis catalytic function obtained in step (2) was immersed in the prepared inert coating for 10 min. After taking out, it was heat cured at a temperature of 50 °C for 300 min to obtain a titanium-based anti-fouling electrode with water electrolysis catalytic performance.

[0083] Comparative Example 1

[0084] The hydrothermal treatment method in step (1) of Example 1 was changed to electrodeposition method, and the other parameters remained unchanged. The scanning electron microscope image of the microstructure of the material is shown in Figure 3 Due to the complex structure of the three-dimensional titanium mesh surface, the deposition layer is too thick when using electrodeposition method, and it is difficult to form a uniform micro-cone array.

[0085] Comparative Example 2

[0086] The hydrothermal time in step (1) of Example 1 was changed to 5 h, and the other parameters were unchanged. The scanning electron microscope image of the microstructure of the material is shown in Figure 4 . Due to the excessive hydrothermal time, the nanowires grown on the surface of the cathode were entangled and could not form a microstructure.

[0087] Comparative Example 3

[0088] The hydrothermal temperature in step (1) of Example 1 was changed to 150°C, and the other parameters were unchanged. The scanning electron microscope image of the microstructure of the material is shown in Figure 5 . When the temperature is reduced to 150°C, the reaction rate of the titanium mesh surface with the strong base is significantly reduced, and the titanate framework cannot grow sufficiently, ultimately only forming sparse and short surface structures.

[0089] Comparative Example 4

[0090] The concentration of sodium hydroxide in step (1) of Example 1 was changed to 4M, and the other parameters were unchanged. Due to the excessively high NaOH concentration, the cathode surface was severely corroded and could not form a microstructure.

[0091] Comparative Example 5

[0092] The immersion time of nickel nitrate in step (2) of Example 1 was changed to 30 h, and the other parameters were unchanged. The scanning electron microscope image of the microstructure of the material is shown in Figure 6 . Due to the excessively long immersion time, a dissolution-recrystallization process occurs in the solution, generating flaky precipitates at the tips of the microstructure, which destroys the microstructure of the cathode.

[0093] Comparative Example 6

[0094] The mass fraction ratio of ultrapure water, dodecanethiol, and acrylic resin in step (3) of Example 2 was changed to 1:20:50, and the other parameters were unchanged. The scanning electron microscope image of the microstructure of the material is shown in Figure 7 . Due to the excessively high concentration of polytetrafluoroethylene, the electrode surface is completely covered with inert paint, losing its conductivity.

[0095] Comparative Example 7

[0096] The immersion time of the inert coating in step (3) of Example 2 was extended to 50 min, and the other parameters were unchanged. The scanning electron microscope image of the microstructure of the material is shown in Figure 8 . Due to the excessively long immersion time, the microstructure of the cathode surface after curing is destroyed by the excessive inert coating, losing its anti-fouling performance.

[0097] Comparative Example 8

[0098] The heat treatment temperature in step (3) of Example 2 was changed to 500°C, and the other parameters were unchanged. Due to the excessively high heat treatment temperature, the inert coating is carbonized, losing its inert effect.

[0099] Comparative Example 9

[0100] The heat treatment temperature in step (3) of Example 2 is changed to 25 ℃, and the other parameters remain unchanged. Due to the too low heat treatment temperature, the inert coating cannot be attached to the surface of the alloy microstructure.

[0101] Comparative Example 10

[0102] The cobalt nitrate solution in step (2) of Example 3 is changed to ammonium nitrate, and the other parameters remain unchanged. Since ammonium nitrate is a non-metallic nitrate salt, the obtained electrode has anti-fouling performance, but loses the water electrolysis catalytic performance.

[0103] Comparative Example 11

[0104] The ion exchange temperature in step (2) of Example 5 is changed from 50 ℃ to 80 ℃, and the other parameters remain unchanged. When the temperature is increased to 80 ℃, the stability of the metal nitrate solution decreases, Co(NO3)2 is partially thermally decomposed to form Co(OH)2 precipitate, and the ion exchange rate is too fast, resulting in Co 2+ does not enter the layered structure, but instead forms a block-shaped deposit on the surface of the microstructure.

[0105] Comparative Example 12

[0106] The 1 M Ni(NO3)2 solution in step (2) of Example 1 is changed to 0.5 M, and the other parameters remain unchanged. When the concentration is reduced to 0.5 M, the amount of Ni 2+ in the solution is insufficient, and the ion exchange reaction is insufficient, with only a small amount of Ni 2+ embedded in the skeleton, resulting in insufficient water electrolysis catalytic activity of the electrode. The voltammogram result shows that the voltage of the electrode at a current density of 100 mA / cm² is more than 0.5 V higher than that of the patent electrode. Figure 9

[0107] Comparative Example 13

[0108] The inert coating formula in step (3) of Example 1 is changed to "dodecanethiol + acrylic resin", and the dispersant ultrapure water is omitted, and the other parameters remain unchanged. The scanning electron microscope image of the microstructure of the obtained material is shown in Figure 10 The role of the dispersant is to make the inert agent (uniformly dispersed in the coating, avoid aggregation, and ensure that only the gap between the microstructures is filled during coating, rather than covering the active tips. After the lack of dispersant, dodecanethiol will form micron-sized aggregates, which cannot enter the gap between the microstructures during coating, but cover the surface of the microstructure tips.

[0109] ​The experiment of magnesium extraction from seawater was carried out in an electrochemical cell. The anode and cathode were RuO2-IrO2-TiO2 / Ti mesh and titanium-based anti-fouling electrode with water electrolysis catalytic function, respectively. The natural seawater from Bohai Bay was selected as the electrolyte, and a direct current power supply was used to apply a constant current density of 100 mA / cm 2 for 100 h. The magnesium hydroxide extracted from seawater is shown in Figure 10 . In order to verify the anti-fouling performance of the electrode, the experiment was carried out under the same conditions using titanium mesh electrode, and the experimental results are shown in Figure 11 and Figure 12 . As can be seen from Figure 11 , the voltage of the anti-fouling electrode remained basically unchanged during the 100 h seawater magnesium extraction experiment, and the reaction voltage was much lower than that of the titanium mesh electrode, while the voltage of the titanium mesh electrode increased from 1 V to 1.75 V. The comparison chart of titanium-based anti-fouling electrode with water electrolysis catalytic function and titanium mesh electrode before and after the reaction is shown in Figure 10 , it can be seen that there is no magnesium hydroxide particle deposition on the surface of the anti-fouling electrode, while the surface of the titanium mesh electrode is completely covered with magnesium hydroxide particles, further proving the superior performance of the titanium-based anti-fouling electrode with water electrolysis catalytic function.

Claims

1. A method for preparing a titanium-based anti-scaling cathode with water electrolysis catalytic function, characterized in that, The steps are as follows: (1) Preparation of cathode with surface microstructure: The titanium mesh is pretreated, and then the dried titanium mesh is placed in a stainless steel reactor lined with polytetrafluoroethylene. 1 M strong alkaline aqueous solution is added, and the titanium mesh is completely immersed in the strong alkaline aqueous solution. The stainless steel reactor is sealed and heated at 180-220℃ for 3-4 hours, and then naturally cooled to room temperature to obtain an electrode with surface microstructure. (2) Preparation of a cathode with a microstructure for water electrolysis catalysis: The electrode with the surface microstructure is immersed in a 1 M metal nitrate solution for ion exchange for 20-24 hours under constant temperature conditions of 50-70℃ to obtain an electrode with a microstructure for water electrolysis catalysis. (3) Construction of inert coating: Prepare an inert coating containing inert reagent, dispersant and binder. Immerse the electrode with microstructure having water electrolysis catalysis function in the inert coating for 10-30 min. After immersion, heat cure the electrode at 50-450 ℃ for 300 min in an inert atmosphere to obtain a titanium-based anti-scaling cathode with water electrolysis catalysis function.

2. The method for preparing a titanium-based anti-scaling cathode with water electrolysis catalysis function according to claim 1, characterized in that, In step (1), the morphology of the surface microstructure is conical, flower-like, or plate-like.

3. The method for preparing a titanium-based anti-scaling cathode with water electrolysis catalytic function according to claim 1, characterized in that, In step (1), the strong alkaline aqueous solution is one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, and barium hydroxide.

4. The method for preparing a titanium-based anti-scaling cathode with water electrolysis catalysis function according to claim 1, characterized in that, In step (2), the metal nitrate is one or a mixture of two or more of nickel nitrate, cobalt nitrate, potassium nitrate, iron nitrate, cerium nitrate, lead nitrate, and calcium nitrate.

5. The method for preparing a titanium-based anti-scaling cathode with water electrolysis catalysis function according to claim 1, characterized in that, In step (3), the mass ratio of inert reagent, dispersant and binder is 0.5-50:0.01-10:0.1-50.

6. The method for preparing a titanium-based anti-scaling cathode with water electrolysis catalysis function according to claim 1, characterized in that, In step (3), the inert reagent is one or more of polytetrafluoroethylene, dodecathiol, perfluorodecyltrimethoxysilane, etc.

7. The method for preparing a titanium-based anti-scaling cathode with water electrolysis catalysis function according to claim 1, characterized in that, In step (3), the dispersant is one or more of xanthan gum, anhydrous ethanol, ultrapure water, etc.

8. The method for preparing a titanium-based anti-scaling cathode with water electrolysis catalysis function according to claim 1, characterized in that, In step (3), the adhesive is one or more of epoxy resin, polydimethylsiloxane, acrylic resin, etc.

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