Chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, preparation method and application thereof

Abstract

The application provides a chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, a preparation method and application, and belongs to the technical field of electrocatalytic materials. The method comprises the following steps: dissolving a ruthenium metal salt and a chromium metal salt in an ethanol solution to obtain a mixed solution; adding a citric acid solution to the mixed solution, mixing and then drying to obtain a dried powder; calcining the dried powder in air to obtain a CrRuO x Chromium-ruthenium oxide catalyst. The chlorine-resistant chromium-ruthenium oxide catalyst prepared by the application can adsorb OH ‑ or water molecules by means of chromium as a Lewis acid site, which not only realizes hydroxyl overflow to effectively repel chloride ions, inhibits the competitive chlorine evolution reaction of the anode in seawater electrolysis, and relieves the corrosion of chloride ions on the catalyst, but also can regulate the interface hydrogen bond network to optimize the adsorption of reaction intermediates, and significantly improves the catalytic activity.

Description

Technical Field

[0001] This invention relates to the field of electrocatalytic materials technology, and in particular to a chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, its preparation method, and its application. Background Technology

[0002] With the global energy structure shifting towards cleaner and renewable energy sources, hydrogen energy, as a clean energy source with zero carbon emissions, has become an important component of the future energy system. Seawater electrolysis for hydrogen production, relying on abundant seawater resources, overcomes the limitations of freshwater resources and has become a significant development direction for large-scale hydrogen production. The electrocatalytic oxygen evolution reaction (OER) is the core half-reaction in seawater electrolysis for hydrogen production. Its slow reaction kinetics are a key factor limiting electrolysis efficiency. Therefore, developing highly efficient OER catalysts suitable for seawater systems has become a research focus and development trend in the fields of electrochemical catalysis and clean energy.

[0003] Currently, ruthenium-based oxides have become an important choice for oxygen evolution reaction (OER) catalytic materials in acidic media and other systems due to their excellent electrocatalytic activity. Researchers have also optimized ruthenium-based oxides through modification methods such as elemental doping to improve their catalytic performance. Some chromium-doped ruthenium-based oxides have already shown improved OER activity in acidic media. Meanwhile, research in the field is gradually revealing that the local microenvironment characteristics of the catalyst surface, such as the water molecule structure and hydrogen bond network, have a decisive influence on the kinetics of the electrocatalytic reaction, providing new research ideas for the design of catalytic materials.

[0004] However, current research on the design and modification of ruthenium-based oxide catalysts focuses primarily on optimizing the bulk electronic structure of the materials themselves, failing to fully consider the complex interfacial environment of seawater electrolysis and thus unable to meet the practical application requirements of seawater systems. In direct seawater electrolysis, chloride ions in the anode region readily trigger a competitive chlorine evolution reaction, significantly reducing the selectivity and oxygen production efficiency of the oxygen evolution reaction and causing severe corrosion to the catalyst materials. Simultaneously, the high salinity of seawater accelerates catalyst dissolution and deactivation. Current technologies have not yet incorporated the local microenvironmental regulation of the catalyst-seawater interface as a design principle for catalyst materials, lacking catalyst materials that can simultaneously achieve high oxygen evolution activity, high chlorine resistance selectivity, and high structural stability in seawater systems. This problem has thus become a key bottleneck restricting the industrialization of direct seawater electrolysis hydrogen production technology. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, the purpose of this invention is to provide a chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, its preparation method, and its application. The chlorine-resistant chromium-ruthenium oxide catalyst prepared by this invention utilizes chromium as a Lewis acid site to adsorb OH. -The presence of water molecules not only enables hydroxyl groups to overflow and effectively repel chloride ions, thus inhibiting the competitive chlorine evolution reaction at the anode in seawater electrolysis and alleviating the corrosion of the catalyst by chloride ions, but also regulates the interfacial hydrogen bond network to optimize the adsorption of reaction intermediates, significantly improving catalytic activity.

[0006] To achieve the above objectives, the present invention provides the following solution: On one hand, the present invention provides a method for preparing a chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, comprising the following steps: S1. Dissolve ruthenium metal salt and chromium metal salt in ethanol solution to obtain a mixed solution; S2. Add citric acid solution to the mixed solution, mix, and then dry to obtain dried powder; S3. The dried powder is calcined in air to obtain CrRuO. x Chromium-ruthenium oxide catalyst.

[0007] Preferably, in S1, the amount of ruthenium metal salt is 0.1-0.3 mmol, and the amount of chromium metal salt is 0.04-0.1 mmol.

[0008] Preferably, in S1, the ruthenium metal salt is ruthenium trichloride or ruthenium acetylacetonate, and the chromium metal salt is chromium trichloride or chromium nitrate.

[0009] Preferably, in S1, the amount of ethanol solution used is 5-20 mL.

[0010] Preferably, in step S2, the concentration of the citric acid solution is 0.5-1.5 mol / L, and the amount of citric acid solution added is 5-20 mL.

[0011] Preferably, in step S2, the drying temperature is 80-160°C and the drying time is 10-20 hours.

[0012] Preferably, in step S3, the calcination temperature is 300-800℃, and the calcination time is 1-5 hours.

[0013] Secondly, the present invention also provides a chlorine-resistant chromium ruthenium oxide catalyst based on seawater electrolysis prepared by the above-described method, wherein the catalyst is CrRuO x As the active host, chromium acts as a Lewis acid site, capable of adsorbing OH groups. - Or water molecules, possessing the characteristics of hydroxyl group overflow and regulating the interfacial hydrogen bond network, can inhibit chloride ion corrosion and optimize the adsorption of reaction intermediates.

[0014] In addition, the present invention also provides an application of the above-mentioned chlorine-resistant chromium ruthenium oxide catalyst based on seawater electrolysis, which is used as an oxygen evolution reaction catalyst in the field of seawater electrolysis to achieve efficient hydrogen production by seawater electrolysis.

[0015] Compared with the prior art, the present invention discloses at least the following technical effects: (1) The CrRuO prepared by this invention x The catalyst utilizes Cr as a Lewis acid site to achieve the effect of OH- - The adsorption of water molecules can trigger a hydroxyl spillover mechanism, effectively repelling chloride ions in seawater, inhibiting competitive chlorine evolution reaction at the anode, and reducing the corrosion of the catalyst by chloride ions. On the other hand, it can regulate the hydrogen bond network at the catalyst-seawater interface, optimize the adsorption process of oxygen evolution reaction intermediates, significantly improve the catalytic activity of the catalyst in the oxygen evolution reaction, and simultaneously achieve high OER activity and high chlorine resistance selectivity.

[0016] (2) The CrRuO of the present invention x The catalyst possesses excellent electrochemical activity and structural stability, enabling it to resist the catalyst dissolution and deactivation problems caused by the high salinity of seawater. It solves the technical problem of easy deactivation of traditional ruthenium-based oxides in seawater electrolysis systems. Furthermore, actual performance tests show that the anodic oxygen evolution performance of this catalyst is significantly better than that of commercially available RuO2 catalysts, demonstrating superior practical application performance in seawater electrolysis oxygen evolution reactions.

[0017] (3) The CrRuO of the present invention x The catalyst preparation method is simple, convenient, and inexpensive. It can be prepared in just three steps: dissolving metal salts, mixing and drying with citric acid, and calcining in an air atmosphere. It does not require complex preparation equipment and process steps, and is easy to scale up. The catalyst prepared lays the technical foundation for the industrial application of seawater electrolysis hydrogen production technology. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating the preparation method of a chlorine-resistant chromium ruthenium oxide catalyst based on seawater electrolysis provided by the present invention; Figure 2 CrRuO prepared in Example 1 of this invention x XRD pattern of the catalyst; Figure 3CrRuO prepared in Example 1 of this invention x TEM image of the catalyst; Figure 4 The graph shows the test results of the anodic oxygen evolution performance provided by this invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, this invention provides a method for preparing a chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, comprising the following steps: S1. Dissolve ruthenium metal salt and chromium metal salt in ethanol solution to obtain a mixed solution.

[0023] Specifically, 0.1-0.3 mmol of ruthenium metal salt and 0.04-0.1 mmol of chromium metal salt are added to 5-20 mL of ethanol solution. The ruthenium metal salt includes, but is not limited to, ruthenium trichloride or ruthenium acetylacetonate, and the chromium metal salt includes, but is not limited to, chromium trichloride or chromium nitrate. The solution is then thoroughly stirred using methods such as ultrasonic dispersion to ensure complete dissolution of the metal salts and the formation of a homogeneous mixture. Ethanol is used as the organic solvent in this step because its excellent solubility allows for thorough dispersion of ruthenium and chromium metal ions, preventing local agglomeration and forming a uniform metal salt dispersion system. This facilitates the subsequent formation of a homogeneous CrRuO₂ solution. x Composite oxides lay the structural foundation, ensuring a uniform distribution of active sites on the final catalyst surface and avoiding a decline in catalytic performance due to uneven composition.

[0024] S2. Add citric acid solution to the mixed solution, mix and then dry to obtain dried powder.

[0025] Specifically, a citric acid solution with a concentration of 0.5-1.5 mol / L and a volume of 5-20 mL is added to the homogeneous mixed solution obtained in S1. The mixture is stirred thoroughly until the entire system is homogeneous and stable. The system is then placed in a drying apparatus and dried at 80-160℃ for 10-20 hours. After drying, the dried precursor powder is collected. In this step, citric acid acts as a complexing agent, reacting with ruthenium and chromium metal ions in the solution to form stable metal complexes, effectively fixing the metal ions and preventing segregation during drying. Controlling the specific drying temperature and time gradually removes ethanol and water from the system, allowing the metal complexes to solidify slowly. This avoids powder cracking and agglomeration due to excessively rapid drying, ensuring the precursor powder has a regular morphology and uniform composition, thus guaranteeing the smooth progress of the subsequent calcination reaction.

[0026] S3. The dried powder is calcined in air to obtain CrRuO. x Chromium-ruthenium oxide catalyst.

[0027] Specifically, the dried powder obtained from S2 is placed in a calcination device such as a tube furnace, maintaining an air atmosphere, and the device is heated to 300-800℃. It is then held at this temperature for 1-5 hours. After calcination, the powder is allowed to cool naturally to room temperature with the furnace to obtain CrRuO. x Chromium-ruthenium oxide catalyst. This step uses air as the oxidizing atmosphere to promote the thermal decomposition and oxidation of the metal complex in the precursor powder. Ruthenium and chromium metal ions are oxidized and combine with oxygen to form a chromium-ruthenium composite oxide (CrRuO). x Based on the aforementioned raw material usage, the range of x can be determined to be 2 ≤ x ≤ 4. Furthermore, during the calcination process, chromium successfully constructed Lewis acid sites, enabling the final catalyst to adsorb OH... - By taking advantage of the properties of water molecules and controlling the temperature and time of calcination, a catalytic structure is formed that enables hydroxyl group overflow and interfacial hydrogen bond network regulation. The crystal structure formed by calcination ensures the structural stability of the catalyst, making it suitable for the harsh environment of high salt and chlorine in seawater.

[0028] The above content will be further described below through specific embodiments. The embodiments provided are only some embodiments of the present invention.

[0029] Example 1 This embodiment aims to provide a method for preparing a chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, specifically including the following steps: Step 1: Dissolve 0.2 mmol of ruthenium trichloride and 0.08 mmol of chromium trichloride in 10 mL of ethanol solution, and disperse by ultrasonication to obtain a homogeneous mixed solution; Step 2: Add 10 mL of 1 mol citric acid solution to the above mixed solution, mix well, and then dry at 140°C to obtain dried powder; Step 3: Place the dried powder in a tube furnace and calcine it at 500°C for 3-5 hours in air atmosphere to obtain CrRuO. x Chromium ruthenium oxide catalyst, where x is 2.6.

[0030] CrRuO prepared based on this embodiment x The composition of the chromium ruthenium oxide catalyst was analyzed using X-ray diffraction (XRD). The XRD results are as follows: Figure 2 As shown. From Figure 2 It can be seen that the CrRuO prepared in this embodiment x The characteristic peaks of the chromium ruthenium oxide catalyst correspond to those of the standard cards (RuO2, Ru), thus confirming that the CrRuO2 catalyst was successfully prepared using the provided method in this embodiment. x catalyst.

[0031] Furthermore, this embodiment also employs field emission transmission electron microscopy (TEM) to examine the prepared CrRuO x The chromium ruthenium oxide catalyst was observed, and the results are as follows: Figure 3 As shown. From Figure 3 It can be seen that the CrRuO prepared in this embodiment x The chromium ruthenium oxide catalyst has a nanosheet structure.

[0032] Example 2 This embodiment aims to provide a method for preparing a chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, specifically including the following steps: Step 1: Dissolve 0.2 mmol of ruthenium trichloride and 0.1 mmol of chromium trichloride in 10 mL of ethanol solution, and disperse by ultrasonication to obtain a homogeneous mixed solution; Step 2: Add 10 mL of 1 mol citric acid solution to the above mixed solution, mix well, and then dry at 120°C to obtain dried powder; Step 3: Place the dried powder in a tube furnace and calcine it at 500°C for 3-5 hours in air atmosphere to obtain CrRuO. x Chromium-ruthenium oxide catalyst, where x is 2.75.

[0033] Example 3 This embodiment aims to provide a method for preparing a chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, specifically including the following steps: Step 1: Dissolve 0.2 mmol of ruthenium trichloride and 0.08 mmol of chromium trichloride in 10 mL of ethanol solution, and disperse by ultrasonication to obtain a homogeneous mixed solution; Step 2: Add 10 mL of 1 mol citric acid solution to the above mixed solution, mix well, and then dry at 160°C to obtain dried powder; Step 3: Place the dried powder in a tube furnace and calcine it at 600°C for 3-5 hours in air atmosphere to obtain CrRuO. x Chromium ruthenium oxide catalyst, where x is 2.6.

[0034] Comparative Example 1 This comparative example aims to further verify the CrRuO prepared in Example 1 using a commercially available RuO2 catalyst. x The performance of chromium ruthenium oxide catalysts, of which the RuO2 catalyst was purchased from Macklin, CAS No. 12036-10-1.

[0035] CrRuO prepared in Example 1 x The anodic oxygen evolution performance of the catalyst and the commercially available RuO2 catalyst of Comparative Example 1 were tested, specifically including: using a three-electrode system, the CrRuO2 catalyst prepared in Example 1 was tested. x Comparative Example 1: Using a commercially available RuO2 catalyst as the anode, a linear scan was performed at a scan rate of 5 mV / s under seawater electrolyte conditions. The results are as follows: Figure 4 As shown. From Figure 4 It can be seen that the CrRuO prepared in Example 1 x The oxygen evolution performance of the chromium-ruthenium oxide catalyst is superior to that of the RuO2 catalyst in Comparative Example 1, further demonstrating the superior oxygen evolution performance of the CrRuO2 catalyst prepared by the method of this invention. x It exhibits excellent electrochemical activity.

[0036] Therefore, the chlorine-resistant chromium-ruthenium oxide catalyst prepared in this invention adsorbs OH using chromium as a Lewis acid site. - The presence of water molecules not only enables hydroxyl groups to overflow and effectively repel chloride ions, thus inhibiting the competitive chlorine evolution reaction at the anode in seawater electrolysis and alleviating the corrosion of the catalyst by chloride ions, but also regulates the interfacial hydrogen bond network to optimize the adsorption of reaction intermediates, significantly improving catalytic activity.

[0037] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0038] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, characterized in that, Includes the following steps: S1. Dissolve ruthenium metal salt and chromium metal salt in ethanol solution to obtain a mixed solution; S2. Add citric acid solution to the mixed solution, mix, and then dry to obtain dried powder; S3. The dried powder is calcined in air to obtain CrRuO. x Chromium-ruthenium oxide catalyst.

2. The preparation method according to claim 1, characterized in that, In S1, the amount of ruthenium metal salt is 0.1-0.3 mmol, and the amount of chromium metal salt is 0.04-0.1 mmol.

3. The preparation method according to claim 2, characterized in that, In S1, the ruthenium metal salt is ruthenium trichloride or ruthenium acetylacetonate, and the chromium metal salt is chromium trichloride or chromium nitrate.

4. The preparation method according to claim 1, characterized in that, In S1, the amount of ethanol solution used is 5-20 mL.

5. The preparation method according to claim 1, characterized in that, In S2, the concentration of the citric acid solution is 0.5-1.5 mol / L, and the amount of citric acid solution added is 5-20 mL.

6. The preparation method according to claim 1, characterized in that, In S2, the drying temperature is 80-160℃ and the drying time is 10-20h.

7. The preparation method according to claim 1, characterized in that, In S3, the calcination temperature is 300-800℃, and the calcination time is 1-5h.

8. A chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis, prepared by the method according to any one of claims 1 to 7, characterized in that, The catalyst is CrRuO x As the active host, chromium acts as a Lewis acid site, capable of adsorbing OH groups. - Or water molecules, possessing the characteristics of hydroxyl group overflow and regulating the interfacial hydrogen bond network, can inhibit chloride ion corrosion and optimize the adsorption of reaction intermediates.

9. The application of the chlorine-resistant chromium-ruthenium oxide catalyst based on seawater electrolysis as described in claim 8, characterized in that, The catalyst is used as an oxygen evolution reaction catalyst in the field of seawater electrolysis to achieve efficient hydrogen production from seawater.

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