A method for rapidly synthesizing a seawater electrolysis self-supporting corrosion-resistant anode catalyst at room temperature and normal pressure

Abstract

The present application relates to a kind of fast synthesis of large current electrolytic seawater self-supporting corrosion-resistant anode catalyst at normal temperature and normal pressure method, comprising the following steps, current collector is placed in the electrolyte containing cobalt chloride, ferric nitrate, cerium nitrate and ammonium chloride and is carried out cathodic electrodeposition, obtain the catalytic electrode material of Cl-intercalated CoFe-LDH composite Ce (OH) 3 heterostructure of electrodeposition on current collector.The synthesis method of the present application process is short, condition is mild, easy to scale production, and the heterostructure catalytic electrode material provided by the present application shows excellent catalytic activity and stability in the anode oxygen evolution reaction of electrolytic seawater hydrogen production, with potential commercial application prospect.The present application has great significance to promote the development of green clean energy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrochemical electrode material preparation, and particularly relates to a Cl - High-current seawater electrolysis anode oxygen evolution reaction electrocatalyst of intercalated CoFe-LDH composite Ce(OH)3 heterostructure and preparation method thereof. BACKGROUND

[0002] The scarcity of fossil fuels and the increase in carbon dioxide emissions have accelerated the exploration of alternative energy sources. Hydrogen energy is considered an ideal clean energy carrier due to its high unit energy density (142 MJ kg -1 ) and non-polluting nature. Water electrolysis technology for hydrogen production is a powerful means to achieve green hydrogen production, as it is pollution-free, can utilize waste heat or electricity generated by renewable intermittent energy sources (wind or solar energy), and produces high-purity hydrogen. However, the global demand for hydrogen will undoubtedly exacerbate the scarcity of freshwater resources. Seawater accounts for about 96.5% of total water resources, and replacing freshwater with seawater for electrolysis to produce hydrogen is a key technology that needs to be addressed for the future development of hydrogen energy. However, impurities such as Cl - , Mg 2+ , Ca 2+ , and microorganisms in seawater pose significant challenges to electrolysis of seawater for hydrogen production.

[0003] Seawater electrolysis cells consist of two half-reactions: the anode oxygen evolution reaction (OER) and the cathode hydrogen evolution reaction (HER). The challenge of electrolysis of seawater for hydrogen production mainly occurs at the anode. The high concentration of Cl - in seawater will compete with OER to generate chlorine (chlorine evolution reaction under acidic conditions) or hypochlorite (chlorine oxidation reaction under alkaline conditions) at the anode. OER is more likely to occur under alkaline conditions, and the theoretical occurrence voltage of OER is 490 mV lower than that of the chlorine oxidation reaction. Using a high-activity catalyst to make the overpotential of OER lower than 490 mV can avoid the occurrence of chlorine oxidation competition and improve the selectivity of OER at the anode. In addition, high concentrations of Cl - can corrode catalytic electrode materials, causing the catalyst to quickly deactivate. It is necessary to construct a Cl - corrosion-resistant catalytic material to ensure that the catalytic electrode material can operate stably for a long time under the conditions of large-current electrolysis of alkaline seawater. The presence of Cl - seriously affects the activity and stability of the anode electrocatalytic material for electrolysis of seawater, and the development of a large-current seawater electrolysis anode catalytic electrode material with high OER activity and Cl - corrosion resistance and short-term large-scale preparation is a key requirement for promoting the development and industrialization of seawater electrolysis for hydrogen production.

[0004] Layered double hydroxides (LDH) have been a hot topic in OER catalyst research in recent years. Among them, CoFe-LDH has shown great application potential due to its excellent OER catalytic activity in water electrolysis anode. Electrodeposition is a preparation method that can quickly synthesize catalytic electrode materials at room temperature and pressure, and is easy to scale up for large-scale preparation. However, the CoFe-LDH currently prepared by electrodeposition mostly uses metal nitrates as raw materials, which makes it have NO3 2- When it is used as an anode catalyst for electrolysis of seawater, it will be rapidly corroded and deactivated. This is because the Cl in seawater - than NO3 2- With stronger intercalation ability, Cl - Will continue to enter the CoFe-LDH interlayer to replace NO3 2- By replacing the high-cost cobalt nitrate raw material with low-cost cobalt chloride and adding a small amount of low-cost ammonium chloride to change the electrolyte environment during deposition, a Cl - Intercalated CoFe-LDH, interlayer Cl - Cl in seawater - The repulsive effect makes it stable for use in seawater electrolysis anodes. In addition, OER is greatly affected by mass transfer behavior. Adding a small amount of cerium nitrate to the electrolyte during electrodeposition can produce Cl - Intercalated CoFe-LDH composite Ce(OH)3 heterostructure electrocatalyst. Ce(OH)3 can be rapidly oxidized to CeO2 during the OER process. Based on the theory of soft and hard acid-base, Ce 4+ It will preferentially adsorb OH in the electrolyte - , which not only further excludes Cl - , but also promoted OH - The mass transfer can accelerate the OER reaction kinetics. Summary of the Invention

[0005] The present invention aims to provide a Cl in situ electrodeposited on a current collector. - Intercalated CoFe-LDH composite Ce(OH)3(CoFe-Cl - The preparation method of / Ce(OH)3) heterostructure catalyst, which can be directly used as a high-current electrolysis seawater anode OER catalytic electrode without the need for additional binders and conductive agents, has good OER catalytic activity and high Cl resistance. - The synthesis method has mild conditions, low cost, and is easy to scale up for production, thus having excellent industrial application prospects.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] A method for synthesizing a seawater electrolysis self-supporting corrosion-resistant anode catalyst with large current at room temperature and normal pressure, the specific steps are as follows:

[0008] (1) Take cobalt chloride hexahydrate, iron nitrate nonahydrate, cerium nitrate hexahydrate and ammonium chloride into deionized water, fully stir and dissolve completely to obtain an electrolyte solution for electrodeposition;

[0009] (2) A double-pair electrode-single working electrode electrodeposition system is adopted, the current collector and the inert electrode plate are connected to the cathode and the anode of the direct current power supply respectively, and are immersed in the electrolyte solution obtained in step (1);

[0010] (3) Constant current density electrodeposition is carried out for a certain time;

[0011] (4) After electrodeposition, the current collector is taken out and washed with water to obtain a Cl - intercalated CoFe-LDH composite Ce(OH)3(CoFe-Cl - / Ce(OH)3) heterostructure catalytic electrode.

[0012] Preferably, the composition of the electrolyte solution in step (1) is: 0.02-0.1M cobalt chloride hexahydrate, 0.01-0.05M iron nitrate nonahydrate, 0.01-0.05M cerium nitrate hexahydrate, and 0.03-0.08M ammonium chloride.

[0013] Preferably, the current collector in step (2) includes foamed nickel, foamed nickel-iron, foamed copper, stainless steel mesh and nickel foil.

[0014] Preferably, the inert electrode plate in step (2) includes graphite plate, platinum sheet, silver sheet, gold sheet and glassy carbon plate.

[0015] Preferably, the distance between the current collector and the inert electrode plate in step (2) is 7-20mm.

[0016] Preferably, the area of the inert electrode plate is greater than that of the current collector in step (2).

[0017] Preferably, the certain time in step (3) is 1-60min.

[0018] Preferably, the current density in step (3) is 1-300mA cm -2 .

[0019] Compared with the existing preparation technology of seawater electrolysis anode catalyst, the synthesis method has the following advantages: (1) mild synthesis conditions, short synthesis time, simple process flow, low cost and large-scale production; (2) the CoFe-Cl -The / Ce(OH)3catalytic electrode is directly used as an anode catalytic electrode for electrolysis of seawater. On one hand, no adhesive needs to be added during use, thereby effectively reducing the internal resistance of the electrode material; on the other hand, the catalytic electrode exhibits excellent OER catalytic activity and effectively resists the corrosion of Cl - in seawater, and has a broad application prospect in the technology of hydrogen production by electrolysis of seawater. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a SEM image of the CoFe-Cl - / Ce(OH)3catalytic electrode prepared in Example 1;

[0021] Figure 2 is a SEM image of the CoFe-Cl - / Ce(OH)3catalytic electrode prepared in Example 1;

[0022] Figure 3 is an elemental distribution map of the CoFe-Cl - / Ce(OH)3catalytic electrode prepared in Example 1 under TEM;

[0023] Figure 4 is an LSV performance graph of the anode OER of the catalytic electrode prepared in Examples 1 to 3 for electrolysis of seawater;

[0024] Figure 5 is an LSV performance graph of the anode OER of the catalytic electrode prepared in Examples 1 and all comparative examples for electrolysis of seawater;

[0025] Figure 6 is a stability performance graph of the anode OER of the catalytic electrode prepared in Example 1 for electrolysis of seawater. DETAILED DESCRIPTION

[0026] In order to more specifically illustrate the present application, further description is made through specific implementation cases. The following examples do not limit the scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

[0027] Example 1:

[0028] (1) 2.7 mmol of cobalt chloride hexahydrate, 1 mmol of iron nitrate nonahydrate, 0.8 mmol of cerium nitrate hexahydrate and 2.4 mmol of ammonium chloride were accurately weighed and added into 50 mL of deionized water, and after being fully stirred and completely dissolved, an electrolyte solution for electrodeposition was obtained;

[0029] (2) A double counter electrode-single working electrode electrodeposition system was used, and a 1 cm x 1 cm nickel foam and two 3 cm x 3 cm graphite plates were connected to the cathode and anode of a direct current power supply, and immersed in the electrolyte solution obtained in step (1);

[0030] (3) Electrodeposition was performed at a constant current density of 120 mA cm -2 for 4 min;

[0031] (4) After electrodeposition, the nickel foam was taken out and washed with water to obtain a Cl - intercalated CoFe-LDH composite Ce(OH)3(CoFe-Cl - / Ce(OH)3) heterostructure catalytic electrode electrodeposited in situ on the nickel foam.

[0032] A three-electrode system was constructed with the CoFe-Cl - / Ce(OH)3 electrodeposited on the nickel foam as the working electrode, a graphite rod as the counter electrode, and a Hg / HgO electrode as the reference electrode, and seawater anode OER performance test was performed. The electrolyte was 1M KOH + seawater.

[0033] Example 2:

[0034] (1) 2.7 mmol of cobalt chloride hexahydrate, 1 mmol of iron nitrate nonahydrate, 0.6 mmol of cerium nitrate hexahydrate, and 2.4 mmol of ammonium chloride were accurately weighed and added to 50 mL of deionized water, and after complete dissolution by stirring, an electrolyte solution for electrodeposition was obtained;

[0035] (2) A double counter electrode-single working electrode electrodeposition system was used, and a 1 cm x 1 cm nickel foam and two 3 cm x 3 cm graphite plates were connected to the cathode and anode of a direct current power supply, and immersed in the electrolyte solution obtained in step (1);

[0036] (3) Electrodeposition was performed at a constant current density of 120 mA cm -2 for 4 min;

[0037] (4) After electrodeposition, the nickel foam was taken out and washed with water to obtain a Cl - intercalated CoFe-LDH composite Ce(OH)3(CoFe-Cl - / Ce(OH)3(0.6)) heterostructure catalytic electrode electrodeposited in situ on the nickel foam.

[0038] The seawater anode OER performance test method was the same as in Example 1.

[0039] Example 3:

[0040] (1) Accurately weigh 2.7 mmol of cobalt chloride hexahydrate, 1 mmol of ferric nitrate nonahydrate, 1 mmol of cerium nitrate hexahydrate, and 2.4 mmol of ammonium chloride and add them to 50 mL of deionized water. Stir thoroughly and dissolve until the solution is completely dissolved to obtain the electrolyte solution used for electrodeposition.

[0041] (2) using a dual counter electrode-single working electrode electrodeposition system, connecting a 1 cm × 1 cm nickel foam and two 3 cm × 3 cm graphite plates to the cathode and anode of a DC power supply, respectively, and immersing them in the electrolyte solution obtained in step (1);

[0042] (3) At 120 mA cm -2 Electrodeposition at a constant current density of 4 min;

[0043] (4) After the electrodeposition is completed, the nickel foam is taken out and washed with water to obtain Cl deposited on the nickel foam in situ. - Intercalated CoFe-LDH composite Ce(OH)3(CoFe-Cl - / Ce(OH)3(1.0)) heterostructure catalytic electrode.

[0044] The OER performance test method of the seawater electrolysis anode is the same as that of Example 1.

[0045] Comparative Example 1:

[0046] (1) Accurately weigh 2.7 mmol of cobalt chloride hexahydrate, 1 mmol of ferric nitrate nonahydrate, and 2.4 mmol of ammonium chloride and add them to 50 mL of deionized water. Stir thoroughly and dissolve them completely to obtain the electrolyte solution used for electrodeposition.

[0047] (2) using a dual counter electrode-single working electrode electrodeposition system, connecting a 1 cm × 1 cm nickel foam and two 3 cm × 3 cm graphite plates to the cathode and anode of a DC power supply, respectively, and immersing them in the electrolyte solution obtained in step (1);

[0048] (3) At 120 mA cm -2 Electrodeposition at a constant current density of 4 min;

[0049] (4) After the electrodeposition is completed, the nickel foam is taken out and washed with water to obtain Cl deposited on the nickel foam in situ. - Intercalated CoFe-LDH (CoFe-Cl - ) catalytic electrode.

[0050] The OER performance test method of the seawater electrolysis anode is the same as that of Example 1.

[0051] Comparative Example 2:

[0052] (1) precisely weigh 2.7 mmol of cobalt nitrate hexahydrate, 1 mmol of iron nitrate nonahydrate and 0.8 mmol of cerium nitrate hexahydrate into 50 mL of deionized water, and after fully stirring and dissolving completely, an electrolyte solution for electrodeposition is obtained;

[0053] (2) a double opposite electrode-single working electrode electrodeposition system is used, 1 cm x 1 cm of foamed nickel and two 3 cm x 3 cm graphite plates are connected to the cathode and anode of a direct current power supply, and are immersed in the electrolyte solution obtained in step (1);

[0054] (3) electrodeposition is carried out at a constant current density of 120 mA cm -2 for 4 min;

[0055] (4) after electrodeposition is completed, the foamed nickel is taken out and washed with water, to obtain a NO3 2- intercalated CoFe-LDH composite Ce(OH)3(CoFe-NO3 2- / Ce(OH)3) heterostructure catalytic electrode electrodeposited in situ on the foamed nickel.

[0056] The method for testing the anode OER performance of the electrolytic seawater is the same as that in Example 1.

[0057] Comparative Example 3:

[0058] (1) precisely weigh 2.7 mmol of cobalt nitrate hexahydrate and 1 mmol of iron nitrate nonahydrate into 50 mL of deionized water, and after fully stirring and dissolving completely, an electrolyte solution for electrodeposition is obtained;

[0059] (2) a double opposite electrode-single working electrode electrodeposition system is used, 1 cm x 1 cm of foamed nickel and two 3 cm x 3 cm graphite plates are connected to the cathode and anode of a direct current power supply, and are immersed in the electrolyte solution obtained in step (1);

[0060] (3) electrodeposition is carried out at a constant current density of 120 mA cm -2 for 4 min;

[0061] (4) after electrodeposition is completed, the foamed nickel is taken out and washed with water, to obtain a NO3 2- intercalated CoFe-LDH (CoFe-NO3 2- ) catalytic electrode electrodeposited in situ on the foamed nickel.

[0062] The method for testing the anode OER performance of the electrolytic seawater is the same as that in Example 1.

[0063] Comparative Example 4:

[0064] (1) Accurately weigh 0.8 mmol of cerium nitrate hexahydrate into 50 mL of deionized water, and after fully stirring and dissolving completely, obtain an electrolyte solution for electrodeposition;

[0065] (2) A double-pair electrode-single working electrode electrodeposition system is used, and a 1 cm x 1 cm foam nickel and two 3 cm x 3 cm graphite plates are connected to the cathode and anode of a direct current power supply, and are immersed in the electrolyte solution obtained in step (1);

[0066] (3) Electrodeposition is carried out at a constant current density of 120 mA cm -2 for 4 min;

[0067] (4) After electrodeposition, the foam nickel is taken out and washed with water to obtain a Ce(OH)3 catalytic electrode electrodeposited in situ on the foam nickel.

[0068] The anodic OER performance test method of the electrolytic seawater is the same as that of Example 1.

[0069] Figure 1 The XRD pattern of the material obtained in Example 1 shows that the CoFe-LDH composite Ce(OH)3 heterostructure catalytic material is deposited on the foam nickel, and the diffraction angle is consistent with CoFe-LDH (PDF # 50-0235) and Ce(OH)3 (PDF # 19-0284).

[0070] Figure 2 The SEM image of the material obtained in Example 1 shows that the catalytic material is deposited in a textured form on the surface of the foam nickel.

[0071] Figure 3 The element distribution map of the material obtained in Example 1 under TEM shows that the elements Co, Fe, Ce, Cl and O are uniformly distributed, and there is no N element, indicating that the CoFe-LDH has Cl - intercalation.

[0072] Figure 4 The LSV graph of the OER of the catalytic material prepared in Example 1 to Example 3 is shown, wherein the material prepared in Example 1 exhibits the optimal anodic OER performance of the electrolytic seawater, and the overpotential is only 329 mV when a large current density of 1000 mA cm -2 is achieved.

[0073] Figure 5 The LSV graph of the OER of the catalytic material prepared in Example 1 and all the comparative examples is shown, and the results also show that the catalytic material obtained in Example 1 exhibits the optimal catalytic activity.

[0074] Figure 6The stability of the catalytic material prepared in Example 1 when applied to electrolytic alkaline seawater anodes was evaluated, and the results showed that it had excellent stability and corrosion resistance of over 200 h at a high current density of 1000 mA cm -2 -2.

Claims

1. A method for the rapid synthesis of a self-supporting corrosion-resistant anode catalyst for the electrolysis of seawater at room temperature and atmospheric pressure, characterized in that, Cl - The intercalated CoFe-LDH composite Ce(OH)3heterostructure electrocatalytic material is in-situ electrodeposited on the current collector, and the synthesis method comprises the following steps: (1) Cobalt chloride hexahydrate, ferric nitrate nonahydrate, cerium nitrate hexahydrate and ammonium chloride are weighed and added into deionized water, and then stirred to completely dissolve to obtain an electrolyte solution for electrodeposition; (2) A double counter electrode-single working electrode electrodeposition system is used, and the current collector and the inert electrode plate are connected to the cathode and the anode of a direct current power supply respectively and immersed into the electrolyte solution obtained in step (1); (3) Constant current density electrodeposition is carried out for a certain time; (4) After the end of electrodeposition, the current collector is taken out and washed with water to obtain Cl - intercalated CoFe-LDH composite Ce(OH)3(CoFe-Cl - / Ce(OH)3) heterostructure catalytic electrode.

2. A process for the rapid synthesis of a self-supporting corrosion resistant anode catalyst for the electrolysis of seawater at room temperature and atmospheric pressure according to claim 1, characterized in that, The electrolyte solution in step (1) comprises 0.02-0.1M cobalt chloride hexahydrate, 0.01-0.05M ferric nitrate nonahydrate, 0.01-0.05M cerium nitrate hexahydrate and 0.03-0.08M ammonium chloride.

3. The process for the rapid synthesis of a self-supporting corrosion resistant anode catalyst for the electrolysis of seawater at room temperature and atmospheric pressure according to claim 1, characterized in that, The current collector in step (2) comprises foamed nickel, foamed nickel-iron, foamed copper, stainless steel mesh and nickel foil.

4. The process for the rapid synthesis of a self-supporting corrosion resistant anode catalyst for the electrolysis of seawater at room temperature and atmospheric pressure according to claim 1, characterized in that, The inert electrode plate in step (2) comprises graphite plate, platinum sheet, silver sheet, gold sheet and glassy carbon plate.

5. The process for the rapid synthesis of a self-supporting corrosion resistant anode catalyst for the electrolysis of seawater at room temperature and atmospheric pressure according to claim 1, characterized in that, The distance between the current collector and the inert electrode plate in step (2) is 7-20mm.

6. The process for the rapid synthesis of a self-supporting corrosion resistant anode catalyst for the electrolysis of seawater at room temperature and atmospheric pressure according to claim 1, characterized in that, The area of the inert electrode plate is greater than that of the current collector in step (2).

7. The process for the rapid synthesis of a self-supporting corrosion resistant anode catalyst for the electrolysis of seawater at room temperature and atmospheric pressure according to claim 1, characterized in that, The certain time in step (3) is 1-60min.

8. The process for the rapid synthesis of a self-supporting corrosion resistant anode catalyst for the electrolysis of seawater at room temperature and atmospheric pressure according to claim 1, characterized in that, The current density in step (3) is 1 to 300 mA cm -2 .

Images