Low-ruthenium dissolution composite electrode, Joule heat preparation method and application of low-ruthenium dissolution composite electrode in alkaline water splitting oxygen desorption

Abstract

The invention discloses a low-ruthenium dissolution composite electrode, a Joule heat preparation method and application of the low-ruthenium dissolution composite electrode in alkaline water splitting oxygen desorption, and belongs to the technical field of electro-catalytic materials. The preparation method comprises the following steps: stirring a substrate in a water-based etching solution containing a ruthenium source, chlorate and urea at a constant temperature for 1-4 hours at 50-80 DEG C, taking out and drying, applying Joule thermal shock under the protection of inert gas, and cooling to room temperature to obtain the low-ruthenium dissolution composite electrode. According to the method, a firm'ruthenium-alloying 'interface is constructed in situ on the stainless steel surface through transient high temperature, so that strong anchoring of ruthenium atoms is realized, and dissolution of ruthenium in a working state is inhibited from the source. The prepared electrode (SSM-Ru) shows excellent comprehensive performance in 1M KOH, the concentration of the ruthenium element in the electrolyte is extremely low (60ppb), and the problem of dissolution failure of a ruthenium-based catalyst is fundamentally solved. The process is simple and convenient, and an innovative scheme is provided for preparing the industrial oxygen evolution electrode with long service life and low cost.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic materials technology, specifically relating to a highly active and stable low-ruthenium dissolution composite electrode, a Joule heating preparation method, and its application in alkaline water cracking for oxygen desorption. Background Technology

[0002] With the continued growth of global energy demand and the escalating crisis of fossil fuel depletion, the energy system is transitioning towards cleaner and lower-carbon energy. The large-scale application of renewable energy sources such as solar and wind power provides a crucial pathway to addressing environmental challenges, but their intermittent, fluctuating, and geographically uneven distribution places higher demands on energy storage and conversion technologies. Against this backdrop, hydrogen energy is considered an ideal energy carrier connecting renewable energy sources with end-use energy scenarios. In the process of water electrolysis, the presence of overpotential leads to increased electricity consumption and a significant decrease in energy utilization efficiency. Catalysts can effectively reduce the overpotential of water electrolysis, thereby improving the utilization rate of electrical energy.

[0003] Currently, the most efficient electrocatalysts for water splitting to produce hydrogen are noble metals such as platinum and palladium, and their corresponding complexes. However, their high cost and low reserves greatly limit their widespread application, leading research focus to the search for alternative, highly efficient catalysts. Numerous electrocatalytic materials have emerged, such as transition metal oxides and sulfides, which, while low in cost, exhibit unsatisfactory stability. Therefore, synthesizing a catalyst that exhibits excellent and stable electrocatalytic properties for water splitting to produce hydrogen under alkaline conditions has significant scientific and practical value. Summary of the Invention

[0004] This invention aims to improve energy conversion efficiency by providing a highly active and stable low-ruthenium dissolution composite electrode, a Joule heating preparation method, and its application in alkaline water cracking for oxygen desorption.

[0005] The present invention discloses a method for preparing a high-activity, high-stability low-ruthenium-leaching composite electrode, which involves stirring the substrate in an aqueous etching solution containing a ruthenium source, chloride salt, and urea at a constant temperature of 50-80°C for 1-4 hours, drying the substrate, subjecting it to Joule thermal shock under inert gas protection, and cooling it to room temperature to obtain the low-ruthenium-leaching composite electrode.

[0006] In the above method, the substrate is a stainless steel substrate, a nickel substrate, or a nickel-iron substrate; further, the substrate is a stainless steel mesh, a nickel mesh, nickel foam, or nickel-iron foam.

[0007] In the above method, the ruthenium source is ruthenium chloride hexahydrate or ammonium ruthenate;

[0008] In the above method, the chloride salt is sodium chloride, ferric chloride, or ammonium chloride;

[0009] In the above method, the mass ratio of ruthenium source, chloride salt and urea in the aqueous etching solution is 1:1~4:0.5~2, preferably 1:2:1;

[0010] In the above method, the constant temperature stirring temperature is 60℃, and the stirring time is 3 hours;

[0011] In the above method, the inert atmosphere is argon atmosphere, the peak temperature of Joule thermal shock is 750~850℃, and the duration is 1~3 seconds; preferably, the peak temperature of Joule thermal shock is 800℃, and the duration is 1~3 seconds.

[0012] This invention utilizes Joule heating transient high-temperature technology to construct a ruthenium-stainless steel alloy interface on a stainless steel substrate, achieving atomic-level anchoring of the active center. The formation of this interface structure enables strong chemical bonding between ruthenium and the substrate elements (Fe, Cr, Ni), fundamentally inhibiting the oxidative dissolution of ruthenium under operating conditions. ICP quantitative analysis shows that after long-term operation in 1M KOH, the ruthenium concentration in the electrolyte of the electrode (SSM-Ru) is only 60 ppb, verifying its extremely low elemental dissolution characteristics and fundamentally suppressing ruthenium dissolution under operating conditions. Thanks to the strong anchoring effect brought by this alloy interface, the composite electrode of this invention achieves a dual breakthrough in catalytic activity and operational lifespan: at 50 mA / cm²... 2 The overpotential at current density is only 269mV, while exhibiting extremely long stability at 50mA / cm. 2 It can operate stably for more than 2200 hours, 1A / cm 2 It can maintain its performance for 1000 hours without significant degradation even at high current densities. Furthermore, the process of this invention is simple, providing an innovative solution for preparing long-life, low-cost industrial oxygen evolution electrodes. Attached Figure Description

[0013] Figure 1 SEM images of the SSM-Ru electrode obtained in Example 1 at different magnifications;

[0014] Figure 2 Surface elemental distribution map of the SSM-Ru electrode obtained in Example 1;

[0015] Figure 3 TEM image of the SSM-Ru electrode obtained in Example 1;

[0016] Figure 4 Polarization curve of the SSM-Ru electrode obtained in Example 1 for oxygen desorption by water cracking in alkaline electrolyte (1M KOH);

[0017] Figure 5 Stability curve of the SSM-Ru electrode obtained in Example 1 for oxygen desorption by water cracking in alkaline electrolyte (1M KOH);

[0018] Figure 6 ICP curves of the SSM-Ru electrode obtained in Example 1 at different times in an alkaline electrolyte (1M KOH). Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0020] Example 1

[0021] Preparation of SSM-Ru electrode: 150 mg ruthenium chloride hexahydrate, 303 mg sodium chloride, and 152 mg urea were dissolved in 45 mL of deionized water to obtain an aqueous etching solution. A 3 cm * 3 cm stainless steel mesh (SSM) was placed in the aqueous etching solution and heated and stirred at 60 °C for 3 h. After removal, it was dried at 60 °C and then rapidly hot-pressed at 800 °C for 1 s in a Joule heating instrument. After cooling to room temperature, a low-ruthenium dissolution composite electrode (SSM-Ru) was obtained.

[0022] The materials prepared by the above method were subjected to SEM and TEM surface morphology testing and electrochemical performance studies.

[0023] Figure 1 The image shows the obtained SEM image of SSM-Ru, which indicates that the sample surface is uniform and smooth.

[0024] Figure 2 The image shows the surface elemental distribution of the obtained SSM-Ru, which indicates that the elements Ni, Fe, Ru, Cr, and O are uniformly distributed on the sample surface.

[0025] Figure 3 The TEM image of the obtained SSM-Ru shows that Ru is uniformly anchored on the surface of the stainless steel mesh, and the surface morphology is uniform and amorphous.

[0026] The electrocatalytic oxygen evolution performance of the prepared SSM-Ru was studied in a three-electrode system with 1M KOH electrolyte, where the SSM-Ru electrode was used as the anode (working area 1*1cm). 2 The platinum wire serves as the counter electrode, and the mercury oxide electrode serves as the reference electrode. It should be noted that the main cell of the electrochemical workstation is the external power source for the electrocatalytic oxygen evolution process; the potential obtained using mercury oxide as the reference electrode is converted into a reversible hydrogen electrode potential in the property diagram.

[0027] Figure 4 The figure shows the electrocatalytic oxygen evolution properties of SSM-Ru in 1M KOH electrolyte. SSM-Ru exhibits these properties at current densities up to 10 mA / cm². 2At this time, the required overpotential is 261 mV, which is 41 mV lower than that of SSM (302 mV). This indicates that the material has low overpotential and high catalytic activity. The horizontal axis represents voltage, and the vertical axis represents current density.

[0028] Figure 5 (a) The current density of SSM-Ru in 1M KOH electrolyte is 50 mA / cm². 2 The constant current stability curve shows that it can remain stable for more than 2200 hours, as shown in the inset. Figure 5 (a) Magnified stability diagram over 1–20 h; Figure 5 (b) The current density in 1M KOH electrolyte is 1A / cm. 2 The constant current stability image shows that the material remains stable for over 1000 hours, indicating high catalytic activity and excellent catalytic stability under alkaline conditions. The horizontal axis represents time, and the vertical axis represents voltage.

[0029] Figure 6 The ICP data of SSM-Ru in 1M KOH electrolyte for different working times show that SSM-Ru exhibits extremely low Ru dissolution and excellent stability during operation. In contrast, the control sample RuO2 shows high Ru desolution and poor stability during operation. The x-axis represents working time, and the y-axis represents concentration.

[0030] To prepare the control sample RuO2, ruthenium chloride hexahydrate was dropped onto carbon paper as a precursor and calcined in a muffle furnace at 350°C for 2 hours with a heating rate of 3°C / h.

[0031] Example 2

[0032] Similar to Example 1, the heating and stirring time at 60°C was changed to 1 h, 2 h, and 4 h to prepare the SSM-Ru electrode. In 1 MkOH electrolyte, the current density reached 10 mA / cm². 2 The required overpotentials are 281mV, 276mV, and 265mV, respectively.

[0033] Example 3

[0034] Similar to Example 1, the mass of ruthenium chloride hexahydrate was changed to 50 mg, 100 mg, and 200 mg to prepare SSM-Ru electrodes. In 1 M KOH electrolyte, the current density reached 10 mA / cm². 2 The required overpotentials are 296 mV, 282 mV and 265 mV, respectively.

[0035] Example 4

[0036] Similar to Example 1, the mass of sodium chloride was changed to 100 mg, 200 mg, and 400 mg to prepare SSM-Ru electrodes. In 1M KOH electrolyte, the current density reached 10 mA / cm². 2 The required overpotentials are 286mV, 274mV, and 278mV, respectively.

[0037] Example 5

[0038] Similar to Example 1, the mass of urea was changed to 50 mg, 100 mg, and 200 mg to prepare SSM-Ru electrodes. In 1 MkOH electrolyte, the current density reached 10 mA / cm². 2 The required overpotentials are 286mV, 274mV, and 278mV, respectively.

[0039] Example 6

[0040] Similar to Example 1, the heating temperatures were changed to 50°C, 70°C, and 80°C to prepare SSM-Ru electrodes. In 1M KOH electrolyte, the current density reached 10 mA / cm². 2 The required overpotentials are 276mV, 264mV and 272mV, respectively.

[0041] From the samples prepared in the above embodiments, it can be seen that the preferred mass ratio of ruthenium source, chloride salt and urea in the etching solution is 1:2:1; the preferred constant temperature stirring time is 60°C and stirring time is 3h; the preferred peak temperature of Joule thermal shock is 800°C and the duration is 1~3 seconds, thereby obtaining a high-activity, high-stability low-ruthenium dissolution composite electrode.

Claims

1. A Joule-thermal preparation method for a low-ruthenium dissolution composite electrode, characterized in that: At 50-80°C, the substrate was stirred at a constant temperature in an aqueous etching solution containing ruthenium source, chloride salt and urea for 1-4 hours. After drying, it was subjected to Joule thermal shock under inert gas protection and cooled to room temperature to obtain a low ruthenium dissolution composite electrode.

2. The Joule heating method for preparing a low-ruthenium dissolution composite electrode as described in claim 1, characterized in that: The substrate can be a stainless steel substrate, a nickel substrate, or a nickel-iron substrate.

3. The Joule heating method for preparing a low-ruthenium dissolution composite electrode as described in claim 2, characterized in that: The substrate is stainless steel mesh, nickel mesh, nickel foam, or nickel-iron foam.

4. The Joule heating method for preparing a low-ruthenium dissolution composite electrode as described in claim 1, characterized in that: The ruthenium source is ruthenium chloride hexahydrate or ammonium ruthenate.

5. The Joule heating method for preparing a low-ruthenium dissolution composite electrode as described in claim 1, characterized in that: Chloride salts are sodium chloride, ferric chloride, or ammonium chloride.

6. The Joule heating method for preparing a low-ruthenium dissolution composite electrode as described in claim 1, characterized in that: In the aqueous etching solution, the mass ratio of ruthenium source, chloride salt and urea is 1:1~4:0.5~2.

7. The Joule heating method for preparing a low-ruthenium dissolution composite electrode as described in claim 1, characterized in that: The inert atmosphere is argon.

8. The Joule heating method for preparing a low-ruthenium dissolution composite electrode as described in claim 1, characterized in that: The peak temperature of Joule thermal shock is 750~850℃, and the duration is 1~3 seconds.

9. A low-ruthenium-leaching composite electrode, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 8.

10. The application of the low ruthenium dissolution composite electrode according to claim 9 in alkaline water cracking for oxygen desorption.

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