A method for resisting sodium chloride crystallization on the cathode surface of electrolyzed seawater

Abstract

The present invention belongs to the field of inorganic advanced nanomaterial technology, and specifically relates to a method for preventing sodium chloride from crystallizing on the surface of a cathode in seawater electrolysis. The method includes at least one of the following two schemes: Scheme 1, the cathode is: a metal ferrocyanide, a metal ferrocyanide, a metal ferrocyanide-loaded material, or a metal ferrocyanide-loaded material; Scheme 2, one or more of ferrocyanide and ferrocyanide are added to the electrolyte. The present invention unexpectedly discovered that the crystal plane of this electrode is a (200) plane with a spacing of about 5 angstroms, while the main crystal plane of sodium chloride is a (200) plane with a spacing of 2.8 angstroms. The two crystal planes are symmetrically matched, but the lattices are not matched, resulting in difficulty for sodium chloride to adhere to the electrode surface. In addition, adding ferrocyanide or ferrocyanide to the electrolyte can also effectively limit the growth of some crystal planes of sodium chloride, thereby controlling the morphology of sodium chloride, making it difficult for it to solidify on the electrode surface, and greatly improving the anti-crystallization stability of the seawater electrolysis cathode.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic advanced nanomaterials, and in particular relates to a method for crystallizing sodium chloride on a cathode surface against electrolysis of seawater. Background Art

[0002] Humanity's demand for hydrogen energy is steadily increasing, but traditional gray and blue hydrogen production is highly susceptible to environmental pollution and exacerbated greenhouse effects. Consequently, hydrogen production through water electrolysis has garnered widespread attention in recent years due to its simple process and lack of pollutants. However, water resources primarily exist in the form of seawater, which accounts for over 96% of global water resources. Large-scale promotion of pure water electrolysis would inevitably increase pressure on global pure water supply, hindering sustainable development. Therefore, seawater electrolysis is imperative.

[0003] However, using seawater as the electrolyte, the net reaction between the cathode and anode of the electrolysis system consumes only water, and the fresh electrolyte replenished is still seawater. Therefore, after prolonged electrolysis, the electrolyte becomes supersaturated with sodium chloride and precipitates. In the initial crystallization phase, crystals tend to grow at the phase interface to reduce the influence of surface energy. This characteristic makes it very easy for sodium chloride crystals to grow on the electrode surface, thereby covering the electrode's active sites and causing electrode inactivation.

[0004] When the electrolyte is seawater with added sodium hydroxide, this crystallization behavior occurs preferentially at the cathode due to the common ion effect.

[0005] In order to solve the above problems, the present invention is proposed. Summary of the Invention

[0006] A first aspect of the present invention provides a method for preventing sodium chloride crystallization on the cathode surface of electrolyzed seawater (hereinafter referred to as anti-salting), wherein the electrolyte for electrolyzing seawater contains one or more of sodium hydroxide, lithium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide and sodium chloride, and the method comprises at least one of the following two schemes:

[0007] Option 1, the cathode catalytic material is: metal ferrocyanide, metal ferrocyanide, metal ferrocyanide supported material or metal ferrocyanide supported material;

[0008] Option 2: Add one or more of ferrocyanide and ferrocyanide to the electrolyte for electrolyzing seawater.

[0009] Preferably, in solution 1, the exposed crystal plane of the metal ferrocyanide or metal ferrocyanide is a (200) plane with a crystal plane spacing of about 5 angstroms.

[0010] In scheme 1, the metal ferrocyanide or metal ferrocyanide is a Prussian blue analogue. Such substances generally spontaneously form a cubic structure with (200) faces as the main component.

[0011] Preferably, in scheme 1, the metal ferrocyanide is: vanadium ferrocyanide, chromium ferrocyanide, manganese ferrocyanide, ferric ferrocyanide, nickel ferrocyanide, cobalt ferrocyanide, copper ferrocyanide, potassium manganese ferrocyanide, potassium copper ferrocyanide, potassium nickel ferrocyanide or potassium cobalt ferrocyanide, and the (200) plane interplanar spacing of each of them is about 5 angstroms;

[0012] The metal ferrocyanide is: vanadium ferrocyanate, chromium ferrocyanate, manganese ferrocyanate, iron ferrocyanate, nickel ferrocyanate, cobalt ferrocyanate, copper ferrocyanate, manganese potassium ferrocyanate, copper potassium ferrocyanate, nickel potassium ferrocyanate or cobalt potassium ferrocyanate, and the (200) plane interplanar spacing is also about 5 angstroms;

[0013] The metal ferrocyanide loading material is: platinum-loaded vanadium ferrocyanide, platinum-loaded chromium ferrocyanide, platinum-loaded manganese ferrocyanide, platinum-loaded ferric ferrocyanide, platinum-loaded nickel ferrocyanide, platinum-loaded cobalt ferrocyanide, platinum-loaded copper ferrocyanide, platinum-loaded potassium manganese ferrocyanide, platinum-loaded potassium copper ferrocyanide, platinum-loaded potassium nickel ferrocyanide or platinum-loaded potassium cobalt ferrocyanide;

[0014] The metal ferrocyanide loading material is: platinum-loaded vanadium ferrocyanide, platinum-loaded chromium ferrocyanide, platinum-loaded manganese ferrocyanide, platinum-loaded ferric ferrocyanide, platinum-loaded nickel ferrocyanide, platinum-loaded cobalt ferrocyanide, platinum-loaded copper ferrocyanide, platinum-loaded potassium manganese ferrocyanide, platinum-loaded potassium copper ferrocyanide, platinum-loaded potassium nickel ferrocyanide or platinum-loaded potassium cobalt ferrocyanide.

[0015] Preferably, in Option 2, the ferrocyanide is added in the form of potassium ferrocyanide or sodium ferrocyanide, and the ferrocyanide is added in the form of potassium ferrocyanide or sodium ferrocyanide.

[0016] Preferably, after adding the ferrocyanide or ferrocyanide, the concentration of the ferrocyanide is 0.1 to 100 mg per milliliter;

[0017] Alternatively, the concentration of the ferrocyanide is 0.1 to 100 mg / ml;

[0018] Alternatively, the total concentration of the ferrocyanide or ferrocyanide is 0.1 to 100 mg / ml.

[0019] Preferably, the electrolyte for electrolyzing seawater contains 6 mol / L sodium hydroxide and 2.8 mol / L sodium chloride.

[0020] The above technical solutions can be freely combined under the premise of no contradiction.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. In the present invention, the addition of ferrocyanide or ferrocyanide to the electrolyte can effectively limit the growth of some crystal faces of sodium chloride, thereby controlling the crystal morphology of sodium chloride, making it difficult for it to solidify on the electrode surface, and greatly improving the anti-crystallization stability of the cathode in the electrolysis of seawater.

[0023] The principle of the ferrocyanide or ferrocyanide anti-crystallization of the present invention is that the coating of the sodium chloride (100) crystal surface by ferrocyanide or ferrocyanide causes the crystal surface to be activated, making it difficult to continue to grow, thereby causing the sodium chloride crystal to grow into a special morphology and increasing the supersaturation of sodium chloride. When the supersaturation of sodium chloride in the solution is low, the formation of crystals is more inclined to heterogeneous nucleation and grow at the phase interface (electrode-electrolyte interface), which is likely to cause electrode inactivation; and after the supersaturation increases, the crystals gradually become mainly homogeneous nucleation and grow in a uniform phase (in the electrolyte). Therefore, the ferrocyanide or ferrocyanide of the present invention can effectively prevent crystallization.

[0024] 2. Furthermore, when the cathode of the present invention contains a metal ferrocyanide or a metal ferrocyanide, sodium chloride crystallization on the cathode surface can be further suppressed. During the electrolysis reaction, the ferrocyanide or ferrocyanide in the cathode acts similarly to the ferrocyanide or ferrocyanide added to the electrolyte, causing sodium chloride crystals to grow into a specific morphology and increasing the sodium chloride supersaturation, effectively preventing crystallization.

[0025] 3. Furthermore, the main exposed crystal plane of this electrode is the (200) plane with a crystal plane spacing of 5 angstroms, while the main exposed crystal plane of sodium chloride in the conventional growth state is the (200) plane with a crystal plane spacing of 2.8 angstroms. As a result, the crystal plane symmetry matches but the lattice does not match, resulting in poor adhesion of sodium chloride on the electrode surface and inability to grow normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the X-ray diffraction pattern of the nickel potassium ferrocyanide electrode in Example 1.

[0027] Figure 2 This is a scanning electron microscope photograph of the nickel potassium ferrocyanide electrode in Example 1.

[0028] Figure 3 This is the linear sweep voltammetry curve of the nickel potassium ferrocyanide electrode in Example 2.

[0029] Figure 4 In Example 3, a nickel foam electrode (solid sphere) and a nickel potassium ferrocyanate electrode (hollow sphere) were used in the electrolyte at -200 mA cm -2 Constant current curve under different current densities.

[0030] Figure 5 This is the X-ray diffraction pattern of the platinum-loaded nickel potassium ferrocyanide electrode in Example 4.

[0031] Figure 6 This is a scanning electron micrograph of the platinum-loaded nickel potassium ferrocyanide electrode of Example 4.

[0032] Figure 7 This is the EDS-Mapping pattern of nickel potassium ferrocyanide loaded with platinum in Example 4.

[0033] Figure 8 The linear sweep voltammetry curve of the platinum-loaded nickel potassium ferrocyanate electrode in Example 5

[0034] Figure 9 In Example 6, a nickel foam electrode (solid sphere) and a platinum-loaded nickel potassium ferrocyanate electrode (hollow sphere) were used in the electrolyte at -200 mA cm -2 Constant current curve under different current densities.

[0035] Figure 10 The X-ray diffraction patterns of the sodium chloride crystals obtained after the constant current test in Example 7 and commercial sodium chloride are shown.

[0036] Figure 11 The following are scanning electron microscope photos of sodium chloride crystals obtained after the constant current test in Example 7 and commercial sodium chloride.

[0037] Figure 12 The EDS element quantitative data (nickel, sodium, potassium) of the platinum-loaded nickel potassium ferrocyanide electrode before and after the constant current test of Example 7.

[0038] Figure 13 In Example 8, a nickel foam electrode was used. No potassium ferrocyanide (solid spheres) or 0.1 mg / mL potassium ferrocyanide (hollow spheres) was added to the electrolyte. The electrolyte was stirred at -200 mA cm -2 12-hour constant current curve under current density and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0039] Figure 14 In Example 9, a nickel foam electrode was used. No potassium ferrocyanide (solid spheres) or 0.5 mg / mL potassium ferrocyanide (hollow spheres) was added to the electrolyte. The electrolyte was stirred at -200 mA cm -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0040] Figure 15In Example 10, a nickel foam electrode was used. No potassium ferrocyanide (solid spheres) or 1 mg / mL potassium ferrocyanide (hollow spheres) was added to the electrolyte. The electrolyte was stirred at -200 mA cm -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0041] Figure 16 In Example 11, a nickel foam electrode was used. No potassium ferrocyanide (solid spheres) or 0.1 mg / mL potassium ferrocyanide (hollow spheres) was added to the electrolyte. The electrolyte was stirred at -200 mA cm -2 12-hour constant current curve under current density and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0042] Figure 17 In Example 12, a nickel foam electrode was used. No potassium ferrocyanide (solid spheres) or 0.5 mg / mL potassium ferrocyanide (hollow spheres) was added to the electrolyte. The electrolyte was stirred at -200 mA cm -2 12-hour constant current curve under current density and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0043] Figure 18 In Example 13, a nickel foam electrode was used. No potassium ferrocyanide (solid spheres) or 1 mg / mL potassium ferrocyanide (hollow spheres) was added to the electrolyte. The electrolyte was stirred at -200 mA cm -2 12-hour constant current curve under different current densities. And the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0044] Figure 19 In Example 14, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used. 0.1 mg / ml potassium ferrocyanide was added and potassium vanadium ferrocyanate electrodes (hollow spheres) were used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0045] Figure 20 In Example 15, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used. 0.1 mg / ml potassium ferrocyanide was added and potassium chromium ferrocyanate electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0046] Figure 21In Example 16, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used. 0.1 mg / ml potassium ferrocyanide was added and potassium manganese ferrocyanate electrodes (hollow spheres) were used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0047] Figure 22 In Example 17, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and potassium ferric ferrocyanate electrodes (hollow spheres) were used, and the electrolyte was charged at -200 mA cm -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0048] Figure 23 In Example 18, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and potassium cobalt ferrocyanate electrodes (hollow spheres) were used, and the electrolyte was charged at -200 mA cm -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0049] Figure 24 In Example 19, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used; 0.1 mg / ml potassium ferrocyanide was added and nickel potassium ferrocyanate electrodes (hollow spheres) were used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0050] Figure 25 In Example 20, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and potassium vanadium ferrocyanate electrode (hollow spheres) was used, and the electrolyte was charged at -200 mA cm -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0051] Figure 26 In Example 21, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and potassium chromium ferrocyanate electrode (hollow spheres) was used, and the electrolyte was charged at -200 mA cm -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0052] Figure 27 In Example 22, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and potassium manganese ferrocyanate electrodes (hollow spheres) were used, and the electrolyte was tested at -200 mA cm -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0053] Figure 28 In Example 23, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and potassium ferric cyanide electrode (hollow spheres) was used, and the electrolyte was charged at -200 mA cm -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0054] Figure 29 In Example 24, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used; 0.1 mg / ml potassium ferrocyanide was added and nickel potassium ferrocyanate electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0055] Figure 30 In Example 25, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and potassium cobalt ferrocyanate electrode (hollow spheres) was used, and the electrolyte was charged at -200 mA cm -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0056] Figure 31 In Example 26, no potassium ferrocyanide was added to the electrolyte (solid spheres) and nickel foam was used. 0.1 mg / ml potassium ferrocyanide was added and a platinum-loaded potassium vanadium ferrocyanate electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0057] Figure 32 In Example 27, no potassium ferrocyanide was added to the electrolyte (solid spheres) and nickel foam was used. 0.1 mg / ml potassium ferrocyanide was added and a platinum-loaded potassium chromium ferrocyanate electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0058] Figure 33 In Example 28, potassium ferrocyanide was not added to the electrolyte (solid spheres) and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and a platinum-loaded potassium manganese ferrocyanate electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0059] Figure 34 In Example 29, potassium ferrocyanide was not added to the electrolyte (solid spheres) and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and a platinum-loaded potassium ferrocyanide electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0060] Figure 35 In Example 30, no potassium ferrocyanide was added to the electrolyte (solid spheres) and nickel foam was used. 0.1 mg / ml potassium ferrocyanide was added and a platinum-loaded potassium cobalt ferrocyanate electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0061] Figure 36 In Example 31, no potassium ferrocyanide was added to the electrolyte (solid spheres) and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and platinum-loaded nickel potassium ferrocyanate electrodes (hollow spheres) were used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0062] Figure 37 In Example 32, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used. 0.1 mg / ml potassium ferrocyanide was added and a platinum-loaded potassium vanadium ferrocyanate electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0063] Figure 38 In Example 33, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used. 0.1 mg / ml potassium ferrocyanide was added and a platinum-loaded potassium chromium ferrocyanate electrode (hollow spheres) was used. -212-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0064] Figure 39 In Example 34, no potassium ferrocyanide (solid spheres) was added to the electrolyte and nickel foam was used. 0.1 mg / ml potassium ferrocyanide was added and a platinum-loaded potassium manganese ferrocyanide electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0065] Figure 40 In Example 35, no potassium ferrocyanide was added to the electrolyte (solid spheres) and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and a platinum-loaded potassium ferricyanide electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0066] Figure 41 In Example 36, no potassium ferrocyanide was added to the electrolyte (solid spheres) and nickel foam was used. 0.1 mg / ml potassium ferrocyanide was added and a platinum-loaded potassium cobalt ferrocyanate electrode (hollow spheres) was used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0067] Figure 42 In Example 37, no potassium ferrocyanide was added to the electrolyte (solid spheres) and nickel foam was used, 0.1 mg / ml potassium ferrocyanide was added and platinum-loaded nickel potassium ferrocyanate electrodes (hollow spheres) were used. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0068] Figure 43 For Example 38, a nickel foam electrode was used. 0.1 mg / mL potassium ferrocyanide (hollow sphere) was added to a 6 mol / L lithium hydroxide and saturated sodium chloride electrolyte. The electrode was charged at -200 mA cm -2 12-hour constant current curve under current density and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0069] Figure 44 For Example 39, a nickel foam electrode was used. 0.1 mg / mL potassium ferrocyanide (hollow spheres) was added to a 6 mol / L potassium hydroxide and saturated sodium chloride electrolyte.-2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0070] Figure 45 For Example 40, a nickel foam electrode was used. 0.1 mg / mL potassium ferrocyanide (hollow sphere) was added to a 6 mol / L electrolyte of rubidium hydroxide and saturated sodium chloride. -2 12-hour constant current curve under current density, and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0071] Figure 46 For Example 41, a nickel foam electrode was used. 0.1 mg / mL potassium ferrocyanide (hollow sphere) was added to a 6 mol / L electrolyte of cesium hydroxide and saturated sodium chloride. The electrolyte was stirred at -200 mA cm -2 12-hour constant current curve under current density and the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0072] Figure 47 In Comparative Example 1, nickel foam electrodes were used in the electrolyte. No silicon dioxide (solid spheres) or 0.1 mg / ml silicon dioxide (hollow spheres) was added to the electrolyte. The electrolyte was heated at -200 mA cm -2 12-hour constant current curve under different current densities. And the crystal mass and weight gain ratio of sodium chloride on the electrode surface (table in the figure).

[0073] Figure 48 In Comparative Example 1, a nickel foam electrode was used, 0.1 mg / mL silicon dioxide (hollow spheres) was added to the electrolyte, and the electrolyte was stirred at -200 mA cm -2 Photograph of the electrode and its surface crystals after 12 hours of testing at the current density. DETAILED DESCRIPTION

[0074] The present invention is further illustrated below by way of examples, but is not limited to these examples. Experimental methods not specifically specified in the examples generally followed conventional conditions, those described in manuals, or those recommended by the manufacturer. The general equipment, materials, and reagents used are commercially available unless otherwise noted. The raw materials required in the following examples and comparative examples are all commercially available.

[0075] The potassium vanadium ferrocyanide, potassium chromium ferrocyanide, potassium manganese ferrocyanide, potassium ferrocyanide iron, potassium cobalt ferrocyanide, vanadium ferrocyanide, chromium ferrocyanide, manganese ferrocyanide, ferric ferrocyanide, cobalt ferrocyanide, platinum-loaded potassium vanadium ferrocyanide, platinum-loaded potassium chromium ferrocyanide, platinum-loaded potassium manganese ferrocyanide, platinum-loaded potassium ferrocyanide iron, platinum-loaded potassium cobalt ferrocyanide, platinum-loaded potassium vanadium ferrocyanide, platinum-loaded potassium chromium ferrocyanide, platinum-loaded potassium manganese ferrocyanide, platinum-loaded potassium ferrocyanide iron, and platinum-loaded potassium cobalt ferrocyanide in this article are all homemade, and the specific method is as follows.

[0076] Example 1 - Preparation of Potassium Vanadium Ferrocyanate, Potassium Chromium Ferrocyanate, Potassium Manganese Ferrocyanate, Potassium Ferric Ferrocyanate, Potassium Cobalt Ferrocyanate, Vanadium Ferrocyanate, Chromium Ferrocyanate, Manganese Ferrocyanate, Ferric Ferrocyanate, and Cobalt Ferrocyanate

[0077] This embodiment uses the following method to prepare nickel potassium ferrocyanide electrode. Of course, those skilled in the art can make adjustments based on the existing technology:

[0078] (1) Prepare 30 ml of a solution: 0.1 g potassium ferrocyanide, 0.1 g nickel nitrate hexahydrate, 1 g polyvinylpyrrolidone-K30, and 0.2 g sodium citrate. Pour the solution into a 50 mL reactor, soak the washed nickel foam in the solution, and place in an oven. The reaction temperature is 120°C for 12 hours. The resulting material is washed three times with water and ethanol, respectively, and dried in a vacuum at 60°C for 10 hours. This is the nickel potassium ferrocyanide electrode.

[0079] (2) The above electrode was subjected to X-ray diffraction. The X-ray diffraction pattern (XRD) is shown in Figure 1 The XRD pattern of potassium nickel ferrocyanide is consistent with the standard card of potassium nickel ferrocyanide. The diffraction peak of the (400) crystal plane is strong. This crystal plane is the second-order diffraction of the (200) crystal plane, indicating the successful synthesis of potassium nickel ferrocyanide with the (200) crystal plane as the main component. The XRD standard card of potassium nickel ferrocyanide also shows that the interplanar spacing of the (200) plane of the above electrodes is about 5 angstroms.

[0080] The scanning electron microscope (SEM) images of the electrode materials are as follows: Figure 2 As shown, potassium nickel ferrocyanide has a trumpet-shaped morphology composed of cubic blocks. Potassium nickel ferrocyanide is a Prussian blue analogue, and Prussian blue analogues have a characteristic cubic block morphology, which also proves the successful synthesis of potassium nickel ferrocyanide.

[0081] Other conditions remain unchanged, and the nickel nitrate hexahydrate in step (1) is replaced with equal masses of: vanadium sulfate heptahydrate, chromium nitrate nonahydrate, manganese nitrate tetrahydrate, ferric nitrate nonahydrate, and cobalt nitrate hexahydrate. Potassium vanadium ferrocyanide, potassium chromium ferrocyanide, potassium manganese ferrocyanide, potassium ferric ferrocyanide, and potassium cobalt ferrocyanide can be prepared respectively.

[0082] Other conditions remain unchanged. The nickel nitrate hexahydrate in step (1) is replaced with equal masses of: vanadium sulfate heptahydrate, chromium nitrate nonahydrate, manganese nitrate tetrahydrate, ferric nitrate nonahydrate, and cobalt nitrate hexahydrate; and the potassium ferrocyanide is replaced with equal masses of potassium ferrocyanide. Vanadium ferrocyanate, chromium ferrocyanate, manganese ferrocyanate, ferric ferrocyanate, and cobalt ferrocyanide can be prepared respectively.

[0083] Example 2 - Performance Test of Electrocatalytic Hydrogen Evolution in Seawater Electrolysis Using Nickel Potassium Ferrocyanate Electrode

[0084] The electrocatalytic hydrogen evolution performance of the nickel potassium ferrocyanide electrode obtained in Example 1 was tested using a three-electrode system: the reference electrode was a calomel electrode, the counter electrode was a carbon rod electrode, and the working electrode was a nickel potassium ferrocyanide electrode with an effective area of ​​1*1 square centimeter. The electrolyte used was a mixed solution of 6.0 mol / L sodium hydroxide and 2.8 mol / L sodium chloride. Cyclic voltammetry was first performed in the range of 0 to -1 V vs RHE until the electrode reached a stable state. After that, a new electrolyte was replaced and a linear scan was performed at 2 mV / s in the range of 0 to -1 V vs RHE. The resulting linear scan voltammogram is shown in FIG. Figure 3 shown.

[0085] Depend on Figure 3 It can be seen that nickel potassium ferrocyanide at -10mA cm -2 At a current density of , the overpotential of the electrocatalytic hydrogen evolution reaction is 300 mV.

[0086] Example 3 - Test of the Anti-crystallization Stability of Nickel Potassium Ferrocyanate Electrode in Seawater Electrolysis

[0087] The cathode anti-crystallization stability of the nickel potassium ferrocyanide electrode of Example 1 was tested using a three-electrode system: the electrolytic cell was an H-type electrolytic cell separated by a Zirfon membrane (a microporous membrane), the reference electrode was a calomel electrode, the counter electrode was a carbon rod electrode, and the working electrode was a nickel potassium ferrocyanide electrode or a foam nickel electrode with an effective area of ​​1*1 square centimeter. The electrolyte used was a mixed solution of 6.0 mol / L sodium hydroxide and 2.8 mol / L sodium chloride. In this electrolyte system, sodium chloride has reached saturation, so as the net consumption of water during the electrolysis process, sodium chloride will be precipitated. The constant current test was carried out at a current density of -200 mA / cm2, and the constant current curve obtained was as shown below. Figure 4 As shown. Figure 4 It can be seen that the use of nickel potassium ferrocyanide electrode can effectively prevent crystallization, so the cathode stability can be maintained for a longer time ( Figure 4 (open circles).

[0088] Example 4 - Preparation of Platinum-loaded Potassium Vanadium Ferrocyanate, Platinum-loaded Potassium Chromium Ferrocyanate, Platinum-loaded Potassium Manganese Ferrocyanate, Platinum-loaded Potassium Ferrocyanide Ferric, Platinum-loaded Potassium Cobalt Ferrocyanate, Platinum-loaded Potassium Vanadium Ferrocyanate, Platinum-loaded Potassium Chromium Ferrocyanate, Platinum-loaded Potassium Manganese Ferrocyanate, Platinum-loaded Potassium Ferric, Platinum-loaded Potassium Cobalt Ferrocyanate

[0089] (1) The preparation method of nickel potassium ferrocyanide electrode is as shown in Example 1. (2) Platinum is loaded on the surface of the electrode by electrodeposition. Electrodeposition is performed using a three-electrode system: the reference electrode is a calomel electrode, the counter electrode is a carbon rod electrode, and the working electrode is a nickel potassium ferrocyanide electrode with an effective area of ​​1*1 square centimeter. The electrolyte is a mixed solution of 6.0 mol / L sodium hydroxide and 2.8 mol / L sodium chloride. 0.1 mol / L chloroplatinic acid is added to the electrolyte and stirred evenly. Three cyclic voltammetric scan cycles are performed in the range of 0 to -1 V vs RHE.

[0090] (2) The above electrode was subjected to X-ray diffraction. The X-ray diffraction pattern (XRD) is shown in Figure 5 , which is consistent with the standard card of nickel potassium ferrocyanide, indicating the successful synthesis of cobalt potassium ferrocyanide; at the same time, no diffraction peak of elemental platinum appears, indicating that the platinum loading on the electrode surface is highly dispersed. The scanning electron microscope (SEM) image of the electrode material is as follows Figure 6 As shown in Figure 2, the platinum-loaded potassium nickel ferrocyanide also exhibits the characteristic cubic block morphology of Prussian blue analogs, which also proves the successful synthesis of potassium nickel ferrocyanide. Figure 7 The EDS-Mapping pattern also proves the uniform loading of platinum on the surface of nickel potassium ferrocyanide.

[0091] Other conditions remain unchanged, and the nickel potassium ferrocyanide electrode in step (1) is replaced with: potassium vanadium ferrocyanide, potassium chromium ferrocyanide, potassium manganese ferrocyanide, potassium ferrocyanide iron, potassium cobalt ferrocyanide, potassium vanadium ferrocyanide, potassium chromium ferrocyanide, potassium manganese ferrocyanide, potassium ferrocyanide iron, and potassium cobalt ferrocyanide. The following can be obtained respectively: potassium vanadium ferrocyanide loaded with platinum, potassium chromium ferrocyanide loaded with platinum, potassium manganese ferrocyanide loaded with platinum, potassium ferrocyanide iron, potassium cobalt ferrocyanide loaded with platinum, potassium vanadium ferrocyanide loaded with platinum, potassium chromium ferrocyanide loaded with platinum, potassium manganese ferrocyanide loaded with platinum, potassium ferrocyanide iron, and potassium cobalt ferrocyanide loaded with platinum.

[0092] Example 5 - Performance Test of Electrocatalytic Hydrogen Evolution in Seawater Electrolysis Using Platinum-Loaded Nickel Potassium Ferrocyanate

[0093] The electrocatalytic hydrogen evolution performance of the platinum-loaded nickel potassium ferrocyanide electrode of Example 4 was tested using a three-electrode system: the reference electrode was a calomel electrode, the counter electrode was a carbon rod electrode, and the working electrode was a platinum-loaded nickel potassium ferrocyanide electrode with an effective area of ​​1*1 square centimeter. The electrolyte used was a mixed solution of 6.0 mol / L sodium hydroxide and 2.8 mol / L sodium chloride. Cyclic voltammetry was first performed in the range of 0 to -1 V vs RHE until the electrode reached a stable state. After that, a new electrolyte was replaced and a linear scan was performed at 2 mV / s in the range of 0 to -1 V vs RHE. The resulting linear scan voltammogram is shown in FIG. Figure 8 shown.

[0094] Depend on Figure 8 It can be seen that the electrocatalytic hydrogen evolution reaction activity of platinum-loaded nickel potassium ferrocyanide is much higher than that of nickel potassium ferrocyanide in Example 2. The electrocatalytic hydrogen evolution reaction activity of platinum-loaded nickel potassium ferrocyanide is much higher than that of platinum-loaded nickel potassium ferrocyanide at -10 mA cm -2 The overpotential is only 19 mV.

[0095] Example 6 - Test of the Anti-crystallization Stability of Nickel Potassium Ferrocyanate Electrode in Seawater Electrolysis

[0096] The cathode anti-crystallization stability of the nickel potassium ferrocyanide electrode of Example 4 was tested using a three-electrode system: the electrolytic cell was an H-type electrolytic cell separated by a Zirfon membrane (a microporous membrane), the reference electrode was a calomel electrode, the counter electrode was a carbon rod electrode, the working electrode was a platinum-loaded nickel potassium ferrocyanide electrode or a foamed nickel electrode with an effective area of ​​1*1 square centimeter, and the electrolyte was a mixed solution of 6.0 mol / L sodium hydroxide and 2.8 mol / L sodium chloride. In this electrolyte system, sodium chloride has reached saturation, so as the net consumption of water during the electrolysis process, sodium chloride will be precipitated. The constant current test was carried out at a current density of -200 mA / cm2, and the constant current curve obtained was as shown below. Figure 9 As shown. Figure 9 It can be seen that the use of nickel potassium ferrocyanide electrode can effectively prevent crystallization, so the cathode stability can be maintained for a longer time (up to 180 hours) ( Figure 9 (open circles).

[0097] Example 7

[0098] After the constant current test of Example 6 is completed, the electrolytic cell is allowed to stand to allow the sodium chloride crystals in the electrolyte to settle, and the sodium chloride crystals at the cathode after the constant current test are collected. The obtained sodium chloride crystals and commercial sodium chloride crystals are subjected to X-ray diffraction analysis, and the diffraction pattern is as follows: Figure 10As shown, it can be clearly seen that the diffraction peak of its (200) crystal plane has decreased significantly, and (200) represents the secondary diffraction of the (100) crystal plane, which indicates that ferrocyanate will activate the (100) crystal plane of sodium chloride, making it difficult for it to grow normally along the (100) crystal plane, thus forming a cubic morphology and solidifying. In addition, the main exposed crystal plane of the nickel potassium ferrocyanide electrode is the (200) with a spacing of 5 angstroms. This crystal plane has the characteristics of crystal plane matching and lattice mismatch with the (200) crystal plane of sodium chloride with a spacing of 2 angstroms. The other main crystal plane of nickel potassium ferrocyanide (220) has a crystal plane spacing of 2 angstroms, which matches the (220) crystal plane of sodium chloride with a spacing of 3.5 angstroms and has a small lattice mismatch, which is conducive to the growth of this crystal plane. This is the reason why the diffraction peak of the (220) plane of sodium chloride crystal increases. Figure 11 Scanning electron microscopy of the obtained sodium chloride crystals (left) and commercial sodium chloride crystals (right) also shows that the obtained sodium chloride crystals have a special morphology, which results in no parallel surfaces between the individual crystals, making it difficult to form a solid block. Figure 12 The EDS data before and after the test show that potassium ions are the majority in the electrode before the reaction, while sodium ions occupy the majority after the reaction. This is because the body center of the face-centered cubic unit cell of nickel potassium ferrocyanide can react with Na + , K + Plasma is stored, and at the beginning of the hydrogen evolution reaction, K + It occupies the body center of the unit cell. As the reaction proceeds, Na + Desolvation and entry into the unit cell center of nickel potassium ferrocyanide effectively reduces the concentration of sodium ions in the double layer of the electrode, making it difficult for sodium chloride to nucleate near the electrode.

[0099] Example 8 - Potassium ferrocyanide additive to control crystallization

[0100] The present invention discovered that the reason why nickel potassium ferrocyanide and platinum-loaded nickel potassium ferrocyanide electrodes prevent electrode surface crystallization is mainly due to the control effect of ferrocyanide on the morphology of sodium chloride. In addition, since some ferrocyanate is reduced to ferrocyanide at the cathode, this morphology control effect can also be achieved. Therefore, the present invention discovered that adding ferrocyanate or ferrocyanide to the electrolyte can also effectively inhibit the occurrence of electrode surface crystallization.

[0101] The specific experiments are as follows:

[0102] The cathode anti-crystallization stability of the potassium ferrocyanide additive in seawater electrolysis of the present invention was tested using a three-electrode system: the reference electrode was a calomel electrode, the counter electrode was a carbon rod, and the working electrode was a commercial nickel foam with an effective area of ​​1*1 square centimeter. 0.1 mg / ml of potassium ferrocyanide was added to a mixed solution of 6.0 mol / L sodium hydroxide and 2.8 mol / L sodium chloride. This mixed solution was used as an electrolyte to perform a constant current test at -200 mA / cm2. The resulting constant current curve is shown below. Figure 13 shown.

[0103] from Figure 13 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 13 The cathode stability is better than that of the control sample without additives ( Figure 13 filled circles).

[0104] The cathode samples obtained after the constant current test in the electrolyte with 0.1 mg / ml potassium ferrocyanide and the electrolyte without potassium ferrocyanide were taken out, and the residual water stains on the surface were absorbed with filter paper, and then dried at 80°C. After weighing the obtained samples, the sodium chloride crystals on the surface of the samples were completely washed off with deionized water, and then weighed again after drying at 80°C. The difference between the mass obtained by the first weighing and the mass obtained by the second weighing is the mass of sodium chloride crystals on the electrode surface, and the ratio of the obtained difference to the mass obtained by the second weighing is the weight gain ratio of sodium chloride crystals on the electrode surface (i.e., the mass of sodium chloride crystals per mg of electrode surface). The anti-crystallization effect of the additive can be judged by comparing the weight gain ratios. The mass and weight gain of sodium chloride crystals on the electrode surface in the two electrolytes with and without potassium ferrocyanide are as follows. Figure 13 As shown in the table.

[0105] Figure 13 The table shows that adding 0.1 mg / ml potassium ferrocyanide to the electrolyte can effectively inhibit crystallization on the electrode surface.

[0106] Example 9

[0107] The test method is as shown in Example 8, but the amount of potassium ferrocyanide added is changed to 10 mg / ml. The constant current curve obtained is as follows: Figure 14 As shown. Figure 14 It can be seen that the electrolyte after adding 10 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 14 The cathode stability is better than that of the control sample without additives ( Figure 14 filled circles).

[0108] The weight gain and weight gain ratio of the cathode sample obtained by adding 10 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 10 mg / ml potassium ferrocyanide were calculated. Figure 14 shown in the table. Figure 14 The table in the middle shows that adding 10 mg / ml potassium ferrocyanide to the electrolyte can effectively inhibit crystallization on the electrode surface.

[0109] Example 10

[0110] The test method is as shown in Example 8, but the amount of potassium ferrocyanide added is changed to 100 mg / ml. The constant current curve obtained is as follows: Figure 15 As shown. Figure 15 It can be seen that the electrolyte after adding 100 mg / ml potassium ferrocyanide has a better anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 15 The cathode stability is better than that of the control sample without additives ( Figure 15 filled circles).

[0111] The weight gain and weight gain ratio of the cathode sample obtained by adding 100 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding potassium ferrocyanide were calculated. Figure 15 shown in the table. Figure 15 The table in the middle shows that adding 100 mg / ml potassium ferrocyanide to the electrolyte can effectively inhibit crystallization on the electrode surface.

[0112] Example 11 - Control of Crystallization by Potassium Ferrocyanide Additive

[0113] The test method is as in Example 8, except that 0.1 mg / ml potassium ferrocyanide is replaced with 0.1 mg / ml potassium ferrocyanide. The constant current curve obtained is as follows: Figure 16 As shown. Figure 16 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferricyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 16 The cathode stability is better than that of the control sample without additives ( Figure 16 filled circles).

[0114] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferricyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferricyanide were calculated. Figure 16shown in the table. Figure 16 The table in the middle shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte can effectively inhibit crystallization on the electrode surface.

[0115] Example 12

[0116] The test method is as in Example 8, except that 0.1 mg / ml potassium ferrocyanide is replaced with 10 mg / ml potassium ferrocyanide. The constant current curve obtained is as follows: Figure 17 As shown. Figure 17 It can be seen that the electrolyte after adding 10 mg / ml potassium ferricyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 17 The cathode stability is better than that of the control sample without additives ( Figure 17 filled circles).

[0117] The weight gain and weight gain ratio of the cathode sample obtained by adding 10 mg / ml potassium ferricyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 10 mg / ml potassium ferricyanide were calculated. Figure 17 As shown in the table, it shows that adding 10 mg / mL potassium ferricyanide to the electrolyte can effectively inhibit the crystallization of the electrode surface.

[0118] Example 13

[0119] The test method is as in Example 8, except that 0.1 mg / ml potassium ferrocyanide is replaced with 100 mg / ml potassium ferrocyanide. The constant current curve obtained is as follows: Figure 18 As shown. Figure 18 It can be seen that the electrolyte after adding 100 mg / ml potassium ferrocyanide has a better anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 18 The cathode stability is better than that of the control sample without additives ( Figure 18 filled circles).

[0120] The weight gain and weight gain ratio of the cathode sample obtained by adding 100 mg / ml potassium ferricyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding potassium ferricyanide were calculated as follows: Figure 18 shown in the table. Figure 18 The table in the middle shows that adding 100 mg / ml potassium ferrocyanide to the electrolyte can effectively inhibit crystallization on the electrode surface.

[0121] Example 14 - Potassium Vanadium Ferrocyanate Coupling Additive

[0122] The test method is as shown in Example 8, except that the nickel foam electrode is replaced with potassium vanadium ferrocyanide electrode, and the comparative example remains unchanged. The constant current curve obtained is as follows: Figure 19 As shown. Figure 19 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 19 The cathode stability is better than that of the control sample without additives ( Figure 19 filled circles).

[0123] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 19 shown in the table. Figure 19 The table in the middle shows that adding 0.1 mg / ml potassium ferrocyanide to the electrolyte can effectively inhibit crystallization on the electrode surface.

[0124] And will Figure 19 Chinese table and Figure 13 Comparing the table in the figure, we can see that: Figure 19 The weight gain of potassium vanadium ferrocyanide electrode is much less than Figure 13 This shows that changing the cathode from nickel foam electrode to potassium vanadium ferrocyanide electrode can further inhibit the crystallization of sodium chloride on the electrode surface.

[0125] Example 15 - Potassium chromium ferrocyanide coupling additive

[0126] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a potassium chromium ferrocyanide electrode. The constant current curve obtained is as follows: Figure 20 As shown. Figure 20 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 20 The cathode stability is better than that of the control sample without additives ( Figure 20 filled circles).

[0127] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 20 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using potassium chromium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0128] Example 16 - Potassium manganese ferrocyanide coupling additive

[0129] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a potassium manganese ferrocyanide electrode. The constant current curve obtained is as follows: Figure 21 As shown. Figure 21 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 21 The cathode stability is better than that of the control sample without additives ( Figure 21 filled circles).

[0130] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 21 This shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using potassium manganese ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0131] Example 17 - Potassium Ferric Ferrocyanate Coupling Additive

[0132] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a potassium ferrocyanide electrode. The constant current curve obtained is as follows: Figure 22 As shown. Figure 22 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 22 The cathode stability is better than that of the control sample without additives ( Figure 22 filled circles).

[0133] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 22 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using potassium ferric ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0134] Example 18 - Potassium Cobalt Ferrocyanate Coupling Additive

[0135] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a potassium cobalt ferrocyanide electrode. The constant current curve obtained is as follows: Figure 23 As shown. Figure 23It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 23 The cathode stability is better than that of the control sample without additives ( Figure 23 filled circles).

[0136] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 23 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using potassium cobalt ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0137] Example 19 - Nickel Potassium Ferrocyanate Coupling Additive

[0138] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a nickel potassium ferrocyanide electrode. The constant current curve obtained is as follows: Figure 24 As shown. Figure 24 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 24 The cathode stability is better than that of the control sample without additives ( Figure 24 filled circles).

[0139] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 24 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using nickel potassium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0140] Example 20 - Potassium Vanadium Ferrocyanate Coupling Additive

[0141] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a potassium vanadium ferrocyanide electrode. The constant current curve obtained is as follows: Figure 25 As shown. Figure 25 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 25 The cathode stability is better than that of the control sample without additives ( Figure 25 filled circles).

[0142] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 25 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using potassium vanadium ferrocyanate electrode can effectively inhibit the crystallization of the electrode surface.

[0143] Example 21 - Potassium chromium ferrocyanate coupling additive

[0144] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a potassium chromium ferrocyanide electrode. The constant current curve obtained is as follows: Figure 26 As shown. Figure 26 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 26 The cathode stability is better than that of the control sample without additives ( Figure 26 filled circles).

[0145] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 26 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using potassium chromium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0146] Example 22 - Potassium manganese ferrocyanide coupling additive

[0147] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a potassium manganese ferrocyanide electrode. The constant current curve obtained is as follows: Figure 27 As shown. Figure 27 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 27 The cathode stability is better than that of the control sample without additives ( Figure 27 filled circles).

[0148] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 27 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using potassium manganese ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0149] Example 23 - Potassium Ferric Ferrocyanate Coupling Additive

[0150] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a potassium ferric ferrocyanide electrode. The constant current curve obtained is as follows: Figure 28 As shown. Figure 28 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 28 The cathode stability is better than that of the control sample without additives ( Figure 28 filled circles).

[0151] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 28 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using potassium ferric ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0152] Example 24 - Potassium Cobalt Ferrocyanate Coupling Additive

[0153] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a potassium cobalt ferrocyanide electrode. The constant current curve obtained is as follows: Figure 29 As shown. Figure 29 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 29 The cathode stability is better than that of the control sample without additives ( Figure 29 filled circles).

[0154] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 29 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using potassium cobalt ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0155] Example 25 - Nickel Potassium Ferrocyanate Coupling Additive

[0156] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a nickel potassium ferrocyanide electrode. The constant current curve obtained is as follows: Figure 30 As shown. Figure 30 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 30 The cathode stability is better than that of the control sample without additives ( Figure 30 filled circles).

[0157] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 30 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using nickel potassium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0158] Example 26 - Platinum-loaded potassium vanadium ferrocyanide coupling additive

[0159] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded potassium vanadium ferrocyanate electrode. The constant current curve obtained is as follows: Figure 31 As shown. Figure 31 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 31 The cathode stability is better than that of the control sample without additives ( Figure 31 filled circles).

[0160] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 31 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded potassium vanadium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0161] Example 27 - Platinum-loaded potassium chromium ferrocyanide coupling additive

[0162] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded potassium chromium ferrocyanate electrode. The constant current curve obtained is as follows: Figure 32 As shown. Figure 32It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 32 The cathode stability is better than that of the control sample without additives ( Figure 32 filled circles).

[0163] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 32 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded potassium chromium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0164] Example 28 - Platinum-loaded potassium manganese ferrocyanide coupling additive

[0165] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded potassium manganese ferrocyanide electrode. The constant current curve obtained is as follows: Figure 33 As shown. Figure 33 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 33 The cathode stability is better than that of the control sample without additives ( Figure 33 filled circles).

[0166] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 33 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded potassium manganese ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0167] Example 29 - Platinum-loaded potassium ferric ferrocyanate coupling additive

[0168] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded potassium ferrocyanide electrode. The constant current curve obtained is as follows: Figure 34 As shown. Figure 34 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 34 The cathode stability is better than that of the control sample without additives ( Figure 34 filled circles).

[0169] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 34 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded potassium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0170] Example 30 - Platinum-loaded cobalt potassium ferrocyanate coupling additive

[0171] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded potassium cobalt ferrocyanate electrode. The constant current curve obtained is as follows: Figure 35 As shown. Figure 35 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 35 The cathode stability is better than that of the control sample without additives ( Figure 35 filled circles).

[0172] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 35 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded potassium cobalt ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0173] Example 31 - Platinum-loaded nickel potassium ferrocyanate coupling additive

[0174] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded nickel potassium ferrocyanate electrode. The constant current curve obtained is as follows: Figure 36 As shown. Figure 36 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 36 The cathode stability is better than that of the control sample without additives ( Figure 36 filled circles).

[0175] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 36 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded nickel potassium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0176] Example 32 - Platinum-loaded potassium vanadium ferrocyanide coupling additive

[0177] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded potassium vanadium ferrocyanide electrode. The constant current curve obtained is as follows: Figure 37 As shown. Figure 37 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 37 The cathode stability is better than that of the control sample without additives ( Figure 37 filled circles).

[0178] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 37 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded potassium vanadium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0179] Example 33 - Platinum-loaded potassium chromium ferrocyanide coupling additive

[0180] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded potassium chromium ferrocyanide electrode. The constant current curve obtained is as follows: Figure 38 As shown. Figure 38 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 38 The cathode stability is better than that of the control sample without additives ( Figure 38 filled circles).

[0181] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 38 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded potassium chromium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0182] Example 34 - Platinum-loaded potassium manganese ferrocyanide coupling additive

[0183] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded potassium manganese ferrocyanide electrode. The constant current curve obtained is as follows: Figure 39 As shown. Figure 39 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 39 The cathode stability is better than that of the control sample without additives ( Figure 39 filled circles).

[0184] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 39 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded potassium manganese ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0185] Example 35 - Platinum-loaded potassium ferric ferrocyanide coupling additive

[0186] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded potassium ferric cyanide electrode. The constant current curve obtained is as follows: Figure 40 As shown. Figure 40 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 40 The cathode stability is better than that of the control sample without additives ( Figure 40 filled circles).

[0187] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 40 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded potassium ferric ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0188] Example 36 - Platinum-loaded cobalt potassium ferrocyanate coupling additive

[0189] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded potassium cobalt ferrocyanide electrode. The constant current curve obtained is as follows: Figure 41 As shown. Figure 41 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 41 The cathode stability is better than that of the control sample without additives ( Figure 41 filled circles).

[0190] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 41 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded potassium cobalt ferrocyanate electrode can effectively inhibit the crystallization of the electrode surface.

[0191] Example 37 - Platinum-loaded nickel potassium ferrocyanate coupling additive

[0192] The test method is as shown in Example 8, but the nickel foam electrode is replaced with a platinum-loaded nickel potassium ferrocyanide electrode. The constant current curve obtained is as follows: Figure 42 As shown. Figure 42 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 42 The cathode stability is better than that of the control sample without additives ( Figure 42 filled circles).

[0193] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml potassium ferrocyanide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml potassium ferrocyanide were calculated. Figure 42 As shown in the table, it shows that adding 0.1 mg / mL potassium ferrocyanide to the electrolyte and using a platinum-loaded nickel potassium ferrocyanide electrode can effectively inhibit the crystallization of the electrode surface.

[0194] Example 38-6 mol / L lithium hydroxide and saturated sodium chloride electrolyte

[0195] The test method is as in Example 8, except that the electrolyte is changed to a mixed solution of lithium hydroxide and saturated sodium chloride. The constant current curve obtained is as follows: Figure 43 As shown. Figure 43 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 43 (open circles).

[0196] Example 39-6 moles per liter of potassium hydroxide and saturated sodium chloride electrolyte

[0197] The test method is as shown in Example 8, but the electrolyte is changed to a mixed solution of potassium hydroxide and saturated sodium chloride. The constant current curve obtained is as follows: Figure 44 As shown. Figure 44 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 44 (open circles).

[0198] Example 40-6 mol / L rubidium hydroxide and saturated sodium chloride electrolyte

[0199] The test method is as in Example 8, except that the electrolyte is changed to a mixture of rubidium hydroxide and saturated sodium chloride. The constant current curve obtained is as follows: Figure 45 As shown. Figure 45 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 45 (open circles).

[0200] Example 41-6 mol / L cesium hydroxide and saturated sodium chloride electrolyte

[0201] The test method is as in Example 8, except that the electrolyte is a mixture of cesium hydroxide and saturated sodium chloride. The constant current curve obtained is as follows: Figure 46 As shown. Figure 46 It can be seen that the electrolyte after adding 0.1 mg / ml potassium ferrocyanide has a good anti-crystallization effect, so it can maintain cathode stability for a long time (at least 12 hours) ( Figure 46 (open circles).

[0202] Comparative Example 1

[0203] Silicon dioxide has the effect of preventing sodium chloride from caking. However, substances that prevent sodium chloride from caking, such as silicon dioxide, do not necessarily prevent sodium chloride from crystallizing.

[0204] The present invention is demonstrated by the following method:

[0205] The test method is as in Example 8, except that 0.1 mg / ml potassium ferrocyanide is replaced with 0.1 mg / ml silicon dioxide. The resulting constant current curve is as follows: Figure 47 As shown. Figure 47 It can be seen that the electrolyte after adding 0.1 mg / mL of silica does not have an anti-crystallization effect, and therefore cannot maintain long-term cathode stability (open circles in the figure below).

[0206] The weight gain and weight gain ratio of the cathode sample obtained by adding 0.1 mg / ml silicon dioxide were weighed and calculated according to the method in Example 8. The mass and weight gain of sodium chloride crystals on the electrode surface in the electrolytes with and without adding 0.1 mg / ml silicon dioxide were calculated. Figure 47 Shown in the table

[0207] Figure 47 As can be seen from the table: compared with the case without adding silica additive, the weight gain of the cathode increases after adding silica (from 317.9 mg to 337.6 mg). Figure 47 The middle table shows that adding 0.1 mg / mL of silicon dioxide to the electrolyte does not inhibit crystallization on the electrode surface.

[0208] Figure 48 In Comparative Example 1, a nickel foam electrode was used, 0.1 mg / mL silicon dioxide (hollow spheres) was added to the electrolyte, and the electrolyte was stirred at -200 mA cm -2 The photo of the electrode and its surface crystals after 12 hours of testing at the current density shows that there are a large number of crystals on the electrode surface.

Claims

1. A method for preventing sodium chloride crystallization on the cathode surface of electrolyzed seawater, characterized in that: The electrolyte for electrolyzing seawater contains alkali and sodium chloride, and the method is as follows: The cathode catalytic material is: metal ferrocyanide, metal ferrocyanide, metal ferrocyanide supported material or metal ferrocyanide supported material; Alternatively, the cathode catalytic material is: metal ferrocyanide, metal ferrocyanide, metal ferrocyanide-supported material or metal ferrocyanide-supported material, and one or more of ferrocyanide and ferrocyanide are added to the electrolyte for electrolyzing seawater; The seawater electrolysis cathode is a seawater electrolysis hydrogen production cathode.

2. The method according to claim 1, characterized in that The exposed crystal plane of the metal ferrocyanide or metal ferrocyanide is a (200) plane with a crystal plane spacing of 5 to 5.5 angstroms.

3. The method according to claim 1, characterized in that The metal ferrocyanide is: potassium vanadium ferrocyanide, potassium chromium ferrocyanide, potassium manganese ferrocyanide, potassium ferric ferrocyanide, potassium nickel ferrocyanide or potassium cobalt ferrocyanide; The metal ferrocyanide is: potassium vanadium ferrocyanate, potassium chromium ferrocyanate, potassium manganese ferrocyanate, potassium iron ferrocyanate, potassium nickel ferrocyanate or potassium cobalt ferrocyanate; The metal ferrocyanide loading material is: platinum-loaded potassium vanadium ferrocyanide, platinum-loaded potassium chromium ferrocyanide, platinum-loaded potassium manganese ferrocyanide, platinum-loaded potassium ferrocyanide, platinum-loaded potassium nickel ferrocyanide or platinum-loaded potassium cobalt ferrocyanide; The metal ferrocyanide loading materials are: platinum-loaded potassium vanadium ferrocyanide, platinum-loaded potassium chromium ferrocyanide, platinum-loaded potassium manganese ferrocyanide, platinum-loaded potassium ferrocyanide, platinum-loaded potassium nickel ferrocyanide, and platinum-loaded potassium cobalt ferrocyanide.

4. The method according to claim 1, wherein The ferrocyanide is added in the form of potassium ferrocyanide or sodium ferrocyanide, and the ferrocyanide is added in the form of potassium ferrocyanide or sodium ferrocyanide.

5. The method according to claim 4, characterized in that After adding the ferrocyanide or ferrocyanide: the concentration of the ferrocyanide is: 0.1-100 mg / ml; Or the concentration of the ferrocyanide is: 0.1-100 mg / ml; Alternatively, the total concentration of the ferrocyanide or ferrocyanide is 0.1 to 100 mg / ml.

6. The method according to claim 1, characterized in that The alkali is one or more of sodium hydroxide, lithium hydroxide, potassium hydroxide, rubidium hydroxide and cesium hydroxide.

7. The method according to claim 1, characterized in that The electrolyte for electrolyzing seawater contains 6 mol / L of alkali and 2.8 mol / L of sodium chloride.

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