Preparation of phosphate-modified carbon quantum dot nickel-based catalyst and use thereof in alkaline seawater electrolysis
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-04-02
- Publication Date
- 2026-08-13
Smart Images
Figure CN2026088136_13082026_PF_FP_ABST
Abstract
Description
Preparation of a phosphate-modified carbon quantum dot nickel-based catalyst and its application in alkaline seawater electrolysis Technical Field
[0001] This invention relates to the field of electrocatalysis and seawater electrolysis for hydrogen production, and in particular to the preparation of a phosphate-modified carbon quantum dot nickel-based catalyst and its application in alkaline seawater electrolysis. Background Technology
[0002] Currently, seawater electrolysis under alkaline conditions is considered one of the feasible technological pathways for large-scale hydrogen production. Nickel-based catalysts, due to their low cost and good catalytic activity, have been extensively studied as anode materials for alkaline water electrolysis. However, natural seawater contains abundant halide ions, especially chloride ions (Cl-). - Although its accumulation on the anode surface has little effect on the oxygen evolution reaction (OER) activity, it can cause electrode instability and corrosion problems.
[0003] Furthermore, although there are studies on improving the structural stability of anode materials in existing technologies, current research mainly focuses on Cl. - The effect on the electrode, and on the bromide ion (Br) - Research on this topic is still relatively lacking. Although Br - While its concentration in seawater is relatively low (approximately 0.6 mM), its larger ionic radius and higher polarizability make it more prone to accumulation at the anode during alkaline seawater electrolysis, leading to more severe electrode corrosion and instability. Therefore, enhancing the resistance of nickel-based electrodes to Cl-... - and Br - Improving the poisoning resistance of nickel-based electrodes and enhancing their stability and OER activity in alkaline seawater electrolysis are urgent technical problems that need to be solved. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing a phosphate-modified carbon quantum dot nickel-based catalyst and its application in alkaline seawater electrolysis, so as to solve the above-mentioned problems in the background art.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] One of the technical solutions of this invention is to provide a method for preparing a phosphate-modified carbon quantum dot nickel-based catalyst (CDs-PO4 / NF), comprising the following steps:
[0007] Citric acid and urea were mixed in water to obtain a carbon quantum dot precursor solution;
[0008] The carbon quantum dot precursor solution, phytic acid, and nickel substrate are mixed and reacted to obtain the phosphate-modified carbon quantum dot nickel-based catalyst.
[0009] Preferably, the molar ratio of citric acid to urea is 1:6.
[0010] Preferably, the concentration of urea in the carbon quantum dot precursor solution is 0-4 mol / L and not 0.
[0011] Preferably, the ratio of the carbon quantum dot precursor solution to phytic acid is 30 mL: 1.1 g.
[0012] Preferably, the reaction temperature is 160-220℃ and the reaction time is 5 h.
[0013] Preferably, the nickel substrate is nickel foam, Ni(OH)2, Ni mesh, or Raney nickel.
[0014] The second technical solution of the present invention provides a phosphate-modified carbon quantum dot nickel-based catalyst prepared according to the above preparation method.
[0015] The third technical solution of the present invention provides an application of the above-mentioned phosphate-modified carbon quantum dot nickel-based catalyst in the field of water electrolysis for hydrogen production.
[0016] Preferably, the application is in the field of hydrogen production by seawater electrolysis.
[0017] More preferably, the application is in the electrolysis of Br-containing... - and Cl - Applications in the field of alkaline seawater hydrogen production.
[0018] Fourth technical solution of the present invention: providing an electrolytic method for containing Br - and Cl - A method for producing hydrogen from alkaline seawater, using the aforementioned phosphate-modified carbon quantum dot nickel-based catalyst as the anode material, in an alkaline seawater containing Br... - and Cl - The oxygen evolution reaction takes place in alkaline seawater.
[0019] The technical principle of this invention is as follows:
[0020] To slow down the corrosion process, previous studies in the art have attempted to employ a single interface modification strategy; however, such methods are ineffective against Br. - The inhibition effect is still insufficient. Meanwhile, while introducing carbon quantum dots (CDs) alone can improve electrode stability to some extent, its catalytic promotion effect on the OER reaction remains limited. Therefore, this invention constructs a composite modification layer of carbon quantum dots and phosphate groups, utilizing their synergistic effect to jointly enhance the catalyst's resistance to halide ion poisoning and its overall catalytic performance.
[0021] In a 1 M KOH + 0.5 M NaBr electrolyte, the phosphate-modified carbon quantum dot nickel-based catalyst (CDs-PO4 / NF) electrode of the present invention exhibits extremely low overpotential, reaching η. 100 =356 mV, which is 219 mV lower than nickel foam substrate (NF), 71 mV lower than carbon quantum dot-modified electrode material (CDs / NF), and 47 mV lower than phosphate-modified electrode material (PO4 / NF).
[0022] In soda ash electrolyte and Br-containing - Cl - In the electrolyte, the catalysts designed in this invention all exhibited excellent OER activity, proving that they all had an inhibitory effect on the poisoning of halide ions.
[0023] In contrast, in Br - In alkaline brine electrolytes, the OER activity of CDs is significantly enhanced; this indicates that in Br... - When present, CDs promote the inhibition of anodic corrosion.
[0024] The beneficial technical effects of the present invention are as follows:
[0025] This invention designs a phosphate-modified carbon quantum dot nickel-based catalyst by introducing a composite modification layer of carbon quantum dots and phosphate groups onto the surface of a nickel substrate. Through the synergistic effect of the PO4 groups and CDs, it significantly promotes OER activity, thereby enabling the catalyst to be used in Br-containing substrates. - and Cl - This composite electrode exhibits excellent oxygen evolution reaction (OER) activity and long-term stability in alkaline seawater. The film-forming and antioxidant properties of carbon quantum dots effectively enhance the stability of the electrode framework, while the Ni3(PO4)2 active phase formed by phosphate modification significantly improves catalytic performance. The synergistic effect of these two components significantly inhibits the poisoning effect of halide ions. Compared to unmodified electrodes and single-modified electrodes, this composite electrode shows significant improvements in OER overpotential and corrosion resistance, demonstrating significant application potential. This invention provides a differentiated halide ion regulation strategy for alkaline seawater electrolysis, significantly enhancing the activity and stability of Ni-based electrocatalysts, and has broad application prospects in large-scale seawater electrolysis for hydrogen production and energy storage conversion.
[0026] The synergistic effect between carbon quantum dots and phosphate groups in this invention stems from the comprehensive effect of the interfacial composite layer they jointly construct. Comparative experiments show that, regardless of whether carbon quantum dots are modified first and then the phosphate layer is introduced, or whether the phosphate layer is constructed first and then carbon quantum dots are loaded, the catalytic performance and stability of the modified structure cannot reach the level of the composite interfacial layer of this invention. Attached Figure Description
[0027] 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.
[0028] Figure 1 shows the linear sweep voltammetry (LSV) curves of the products of Examples 1-3 and when nickel foam is used as the working electrode, under the electrolyte conditions of 1 M KOH + 0.5 M NaBr.
[0029] Figure 2 shows the linear sweep voltammetry (LSV) curves of the products of Example 1, Comparative Examples 1-2, and when nickel foam is used as the working electrode, under the electrolyte conditions of 1 M KOH + 0.5 M NaBr.
[0030] Figure 3 shows the linear sweep voltammetry (LSV) test curves of the products of Example 1, Comparative Examples 1-2, and 7-8, as well as the product with nickel foam as the working electrode, under the condition of 1 M KOH electrolyte.
[0031] Figure 4 shows the linear sweep voltammetry (LSV) test curves of the products of Example 1, Comparative Examples 1-2, and when nickel foam is used as the working electrode, under the electrolyte conditions of 1 M KOH + 0.5 M NaCl.
[0032] Figure 5 shows the linear sweep voltammetry (LSV) curves of the products of Example 1 and Comparative Examples 3-4 as working electrodes under the conditions of 1 M KOH + 0.5 M NaBr electrolyte.
[0033] Figure 6 shows the linear sweep voltammetry (LSV) curves of the products of Example 1 and Comparative Examples 5-6 as working electrodes under the conditions of 1 M KOH + 0.5 M NaBr electrolyte.
[0034] Figure 7 shows the linear sweep voltammetry (LSV) curves of the products of Example 1 and Comparative Example 9, as well as the product of nickel foam as the working electrode, under the electrolyte conditions of 1 M KOH + 0.5 M NaBr.
[0035] Figure 8 shows the linear sweep voltammetry (LSV) curve of the product of Example 1 as the working electrode under the electrolyte conditions of 1 M KOH + 0.5 M NaBr + 0.5 M NaCl. Detailed Implementation
[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.
[0037] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. It should be noted that any aspects of this invention not described in detail are conventional practices in the art and are not the focus of this invention.
[0039] The terms “comprising,” “including,” “having,” “containing,” etc., used in this invention are all open-ended terms, meaning that they include but are not limited to.
[0040] Unless otherwise specified, "room temperature" in this invention refers to 10-30°C.
[0041] The thickness of the fresh nickel foam used in the following embodiments and comparative examples of the present invention is 1 mm.
[0042] All raw materials used in the following embodiments and comparative examples of the present invention are commercially available products.
[0043] Example 1
[0044] A method for preparing a phosphate-modified carbon quantum dot nickel-based catalyst, comprising the following steps:
[0045] (1) Mix 3.84 g citric acid (0.02 mol) and 7.2 g urea (0.12 mol) in 30 mL deionized water and stir for 30 min to obtain a colorless mixed solution;
[0046] (2) Take 10 mL of the mixed solution and add deionized water to make up to 30 mL of carbon quantum dot precursor solution;
[0047] (3) Add 1.1 g of phytic acid to the carbon quantum dot precursor solution, stir for 30 min, then put in 2 cm × 3 cm fresh nickel foam, sonicate for 5 min, transfer to 50 mL reactor, and hydrothermally react at 220℃ for 5 h. After the reaction, cool naturally to room temperature, and after washing with ethanol and water, obtain phosphate-modified carbon quantum dot nickel-based catalyst, denoted as CDs-PO4 / NF-10.
[0048] Example 2
[0049] The only difference from Example 1 is that step (2) is modified as follows:
[0050] Take 5 mL of carbon quantum dot precursor solution and add deionized water to make up to 30 mL of mixed solution. The final product is denoted as CDs-PO4 / NF-5.
[0051] Example 3
[0052] The only difference from Example 1 is that step (2) is modified as follows:
[0053] Measure 20 mL of carbon quantum dot precursor solution and add deionized water to make a final volume of 30 mL. The final product is denoted as CDs-PO4 / NF-20.
[0054] Comparative Example 1 (phosphate modification omitted)
[0055] A method for preparing a carbon quantum dot nickel-based catalyst, comprising the following steps:
[0056] (1) Mix 3.84 g citric acid (0.02 mol) and 7.2 g urea (0.12 mol) in 30 mL deionized water and stir for 30 min to obtain a colorless mixed solution;
[0057] (2) Take 10 mL of the mixed solution and add deionized water to make up to 30 mL of carbon quantum dot precursor solution;
[0058] (3) Place 2 cm × 3 cm fresh nickel foam in carbon quantum dot precursor solution, sonicate for 5 min, transfer to 50 mL reactor, and hydrothermally react at 220℃ for 5 h. After the reaction, cool naturally to room temperature, and wash with ethanol and water to obtain carbon quantum dot nickel-based catalyst, denoted as CDs / NF-10.
[0059] Comparative Example 2 (carbon quantum dot layer omitted)
[0060] A method for preparing a phosphate-modified nickel-based catalyst, comprising the following steps:
[0061] Add 1.1 g of phytic acid to 30 mL of deionized water and stir for 30 min. Then add 2 cm × 3 cm of fresh nickel foam, sonicate for 5 min, transfer to a 50 mL reactor, and hydrothermally react at 220 °C for 5 h. After the reaction, allow it to cool naturally to room temperature. After washing with ethanol and water, obtain the phosphate-modified nickel-based catalyst, denoted as PO4 / NF.
[0062] Comparative Example 3 (CQDs first, then PA)
[0063] The CDs / NF-10 prepared in Comparative Example 1 and 1.1 g of phytic acid were poured into 30 mL of deionized water, stirred for 30 min, transferred to a 50 mL reactor, and hydrothermally reacted at 220℃ for 5 h. After the reaction, the mixture was naturally cooled to room temperature and washed with ethanol and water. The resulting product was denoted as CDs-10 / NF-PO4.
[0064] Comparative Example 4 (PA first, then CQDs)
[0065] 3.84 g citric acid (0.02 mol) and 7.2 g urea (0.12 mol) were mixed in 30 mL of deionized water and stirred for 30 min to obtain a colorless mixed solution.
[0066] Take 10 mL of the mixed solution and add deionized water to make up to 30 mL of carbon quantum dot precursor solution;
[0067] PO4 / NF prepared in Comparative Example 2 was added to the carbon quantum dot precursor solution, sonicated for 5 min, transferred to a 50 mL reactor, and hydrothermally reacted at 220℃ for 5 h. After the reaction, the mixture was naturally cooled to room temperature and washed with ethanol and water to obtain a carbon quantum dot nickel-based catalyst, denoted as PO4 / NF-CDs-10.
[0068] Comparative Example 5 (Carbon quantum dot modification was changed to carbon nanotube modification)
[0069] A method for preparing a phosphate-modified carbon nanotube nickel-based catalyst, comprising the following steps:
[0070] Mix 3.6 g of glucose in 30 mL of deionized water and stir for 30 min to obtain a colorless carbon nanotube precursor solution.
[0071] Take 10 mL of carbon nanotube precursor solution and add deionized water to make up to 30 mL of mixed solution.
[0072] 1.1 g of phytic acid was added to the mixed solution and stirred for 30 min. Then, fresh nickel foam of 2 cm × 3 cm was added, sonicated for 5 min, and transferred to a 50 mL reactor. The reaction was carried out hydrothermally at 220 °C for 5 h. After the reaction, the solution was naturally cooled to room temperature. After washing with ethanol and water, the phosphate-modified carbon nanotube nickel-based catalyst was obtained, denoted as CNTs-PO4 / NF-10.
[0073] Comparative Example 6 (the active phase of Ni3(PO4)2 was modified to nickel phosphide NiP) x (active phase)
[0074] A method for preparing a nickel-based catalyst modified with nickel phosphide and carbon nanotubes, comprising the following steps:
[0075] Add 0.44 g of sodium hypophosphite to 10 mL of deionized water to obtain a sodium hypophosphite solution;
[0076] The CDs / NF-10 prepared in Comparative Example 1 was immersed in a sodium hypophosphite solution and allowed to stand for 2 h. After removal, it was placed in a porcelain boat and calcined in a tube furnace under an Ar atmosphere. The procedure was as follows: initial temperature 20 ℃, temperature increased to 350 ℃ at a rate of 11 ℃ / min, held at that temperature for 2 h, and then cooled to room temperature to obtain a nickel-phosphide modified carbon nanotube nickel-based catalyst, denoted as CDs-NiP. x / NF-10.
[0077] Comparative Example 7
[0078] The only difference from Comparative Example 1 is that step (2) is modified as follows:
[0079] Take 5 mL of the mixed solution and add deionized water to make up to 30 mL of carbon quantum dot precursor solution. The final product is denoted as CDs / NF-5.
[0080] Comparative Example 8
[0081] The only difference from Comparative Example 1 is that step (2) is modified as follows:
[0082] Take 20 mL of the mixed solution and add deionized water to make up to 30 mL of carbon quantum dot precursor solution. The final product is denoted as CDs / NF-20.
[0083] Comparative Example 9
[0084] The only difference from Example 1 is that phytic acid was replaced with an equal mass of phosphorous acid. The final product was designated CDs-PO3 / NF-10.
[0085] Effect verification
[0086] Electrochemical performance testing
[0087] The OER performance of the products from each example and comparative example was tested in electrolytes of 1 M KOH, 1 M KOH + 0.5 M NaCl, 1 M KOH + 0.5 M NaBr, and 1 M KOH + 0.5 M NaBr + 0.5 M NaCl, and the performance was compared with that of the treatment group using nickel foam (NF) as the working electrode. Specifically, the working electrode was a 1.5 × 1 cm sample, the reference electrode was a Hg / HgO electrode, and the counter electrode was a graphite carbon rod. Before the electrochemical test, the electrolyte was saturated with oxygen for 30 min, and the scan rate was 0.1 V / s within the range of 1.2–1.8 V vs. RHE for 100 cycles. The LSV test procedure was the same: 1.2–1.8 V vs. RHE with a scan rate of 0.01 V / s.
[0088] Figure 1 shows the linear sweep voltammetry (LSV) curves of the products of Examples 1-3 and when nickel foam is used as the working electrode, under the electrolyte conditions of 1 M KOH + 0.5 M NaBr.
[0089] Figure 2 shows the linear sweep voltammetry (LSV) curves of the products of Example 1, Comparative Examples 1-2, and when nickel foam is used as the working electrode, under the electrolyte conditions of 1 M KOH + 0.5 M NaBr.
[0090] Figure 3 shows the linear sweep voltammetry (LSV) test curves of the products of Example 1, Comparative Examples 1-2, and 7-8, as well as the product with nickel foam as the working electrode, under the condition of 1 M KOH electrolyte.
[0091] Figure 4 shows the linear sweep voltammetry (LSV) test curves of the products of Example 1, Comparative Examples 1-2, and when nickel foam is used as the working electrode, under the electrolyte conditions of 1 M KOH + 0.5 M NaCl.
[0092] Figure 5 shows the linear sweep voltammetry (LSV) curves of the products of Example 1 and Comparative Examples 3-4 as working electrodes under the conditions of 1 M KOH + 0.5 M NaBr electrolyte.
[0093] To rule out the order effect, additional validations were performed using CDs-10 / NF-PO4 (CQDs first, then PA) and PO4 / NF-CDs-10 (PA first, then CDs). As shown in Figure 5, each treatment group showed [results] at η [the time frame / percentage]. 100 The performance of the product of Example 1 of this invention is significantly better than that of the products of Comparative Examples 3-4, indicating that the synergistic effect mainly comes from the "interface composite layer" rather than the hierarchical structure.
[0094] Figure 6 shows the linear sweep voltammetry (LSV) curves of the products of Example 1 and Comparative Examples 5-6 as working electrodes under the conditions of 1 M KOH + 0.5 M NaBr electrolyte.
[0095] In Comparative Example 5, glucose was used as the carbon precursor, which is the main raw material for synthesizing carbon nanotubes (CNTs). As shown in Figure 6, the performance of the product in Comparative Example 5 is significantly lower than that in Example 1. This is mainly because CQDs (zero-dimensional) have ultra-small size and abundant surface active sites, resulting in high surface exposure and tight coupling with the Ni surface / NiOOH active phase, forming a large number of interfacial electron exchange channels; while CNTs (one-dimensional), although having better conductivity, have mostly inert sp24-particle-coated walls. 2 Carbon, in its application, only has active sites at the tube ends and defect sites, with relatively fewer active sites than CQDs. Furthermore, CNTs arranged on NFs tend to form a "hydrophobic array," reducing electrolyte wetting and interfacial contact. Therefore, the CQDs of Example 1 more readily utilize surface activity, while CNTs are limited by the number of effective active sites.
[0096] For nickel foam substrates: The CQDs modification in Example 1 can enrich the catalyst surface with oxygen / nitrogen functional groups, which can regulate the local charge distribution and enable Br... - It is more difficult for them to adsorb on active NiOOH sites, thus mitigating the poisoning effect. However, the CNT modification in Comparative Example 5 results in a catalyst surface that is essentially graphitized carbon, lacking functional group regulation, which may actually promote Br... - Retention at the Ni / C interface leads to a significant decrease in activity. The CQDs in Example 1 can mitigate the effect of Br... - Poisoning, while CNTs with a ratio of 5 are easily toxicized by Br. - Competitive adsorption inhibition.
[0097] Regarding electronic structure and interface coupling: The CQDs in Example 1 exhibit a significant quantum confinement effect, with strong electronic coupling between the band structure and Ni / NiOOH, facilitating rapid charge transfer and benefiting OER kinetics. Comparative Example 5, on the other hand, is predominantly quasi-metallic with weaker electronic coupling, acting more as a conductive framework than directly modulating interface electrons. Due to the quantum confinement effect, the CQDs demonstrate stronger interface coupling, resulting in a more direct improvement in activity.
[0098] Regarding bubble release and mass transfer: In Comparative Example 5, the CNTs formed a denser array on the NF, leading to bubble retention and impaired mass transfer. In contrast, the CQDs modification in Example 1 hardly changed the open-pore structure of the NF, resulting in smoother bubble release.
[0099] Comparative Example 6 was calcined in a sodium hypophosphite and Ar atmosphere to produce nickel phosphides (Ni2P, Ni... 12P5 and other phases), at this time the main phase is nickel phosphide (NiP). x ).
[0100] As shown in Figure 6, the performance of the product in Comparative Example 6 is also lower than that in Example 1. This is mainly because the Ni3(PO4)2 (phosphate species) in the product of Example 1 of this invention is more easily converted into a NiOOH-like active phase during the electrochemical process in an alkaline electrolyte, while PO4 3- As an anion regulator, it can inhibit Br - Competitive adsorption at active sites leads to improved OER performance. In contrast, NiP in Comparative Example 6... x Although nickel phosphide species can also undergo surface reconstruction under alkaline conditions, their transformation into the true active NiOOH phase requires a "phosphorus dissolution-Ni oxidation" process, which is relatively slow. Moreover, the residual phosphide structure reduces the hydrophilicity and conductivity of the electrode, thus limiting the OER performance.
[0101] Figure 7 shows the linear sweep voltammetry (LSV) curves of the products of Example 1 and Comparative Example 9, as well as the product of nickel foam as the working electrode, under the electrolyte conditions of 1 M KOH + 0.5 M NaBr.
[0102] As shown in Figure 7, after modifying the catalyst electrode material with phosphorous acid (Comparative Example 9) as the phosphorus source, the resulting catalyst electrode material exhibits better performance against Br-containing... - The activity of the alkaline solution was not improved. This is mainly because phytic acid-modified Lewis base phosphates can better enhance the absorption capacity of hydroxides and accelerate NF surface reconstruction.
[0103] Figure 8 shows the linear sweep voltammetry (LSV) curve of the product of Example 1 as the working electrode under the electrolyte conditions of 1 M KOH + 0.5 M NaBr + 0.5 M NaCl.
[0104] The experimental results above show that CDs-PO4 / NF-10 exhibits the lowest overpotential in all these electrolytes.
[0105] In summary, this invention introduces carbon quantum dots (CDs) and phosphate (PO4) ions onto the surface of a nickel foam substrate. 3- The composite modification layer of ) constructs a stable and efficient electrode interface.
[0106] The role of carbon quantum dots
[0107] Enhanced interface stability: CDs have good film-forming properties and oxidation resistance, and can form a dense and uniform coating layer on the surface of nickel foam, effectively slowing down the corrosion of electrodes in strong alkaline and halide ion environments.
[0108] Electronic structure modulation: The quantum confinement effect of CDs brings abundant surface energy levels and defect sites, which can enhance the rapid transfer of electrons between the Ni-based framework and the electrolyte interface.
[0109] Selective inhibition of Br - Poisoning: In the presence of Br - In the electrolyte, oxygen / nitrogen functional groups on the surface of CDs can regulate the local charge distribution, thereby weakening the Br... - Strong adsorption at active sites enhances OER kinetics.
[0110] The role of phosphate
[0111] Active phase formation: Phytic acid promotes Ni and PO4 under hydrothermal conditions 3- The reaction produces a stable Ni3(PO4)2 phase. During alkaline electrolysis, this phase can be converted in situ into highly reactive NiOOH, while residual PO4... 3- The group acts as an anion regulator, which can synergistically interact with NiOOH to enhance its OER activity.
[0112] Anti-halogen poisoning effect: PO4 3- A stable anionic coordination environment is formed on the surface, which can react with adsorbed OH groups. - Competition is formed, inhibiting Cl - / Br - The occupation of active sites effectively mitigates the poisoning of catalysts by halide ions.
[0113] CDs and PO4 3- Synergistic effect
[0114] Interface Co-coupling: CDs provide a stable and conductive carbon-based interface, PO4 3- The introduction of [the substance] promotes the formation of the active Ni3(PO4)2 phase, and the two form a composite layer at the interface, which enhances the compatibility between the electrode and the electrolyte.
[0115] Dual protection mechanism: CDs layer prevents electrode skeleton corrosion, PO4 3- By regulating adsorption selectivity, the two can work synergistically to simultaneously improve structural stability and reaction kinetics.
[0116] Broad-spectrum antihalogen properties: CDs in Br - It plays a prominent role in the environment, while PO4 3- For Cl - / Br - Both can effectively suppress the poisoning effect, and the composite electrode exhibits excellent electrochemical stability in different halogen systems.
[0117] Performance advantages and mechanism summary
[0118] Activity enhancement: The Ni3(PO4)2 phase is transformed into highly active NiOOH during the OER process, while CDs promote interfacial electron transport, resulting in a significant reduction in OER overpotential.
[0119] Enhanced stability: CDs film formation protection and PO4 3- The synergistic effect of regulation effectively inhibits the corrosion and poisoning of electrodes in strong alkaline and halide ion environments, achieving long-term operational stability.
[0120] Selective antitoxicization: Composite modification layer on Br - The anti-toxic effect is particularly obvious, and at the same time in Cl - The existence of this strategy demonstrates its advantages, proving its broad applicability.
[0121] Synergistic mechanism: The performance improvement is not due to a single component, but rather stems from the stability of the CDs interface and PO4. 3- Synergistic effect of induced active phase and dual protective effect.
[0122] In this invention, sulfate groups and carbon quantum dots are synergistically modified on the surface of nickel foam to form a stable and dense composite interface layer. Unlike layered modification methods (i.e., introducing sulfate groups first and then loading carbon quantum dots, or modifying carbon quantum dots first and then introducing sulfate groups), synergistic modification achieves the following technical effects and principles:
[0123] 1. Electronic structure regulation: The interaction between sulfate groups and carbon quantum dots can optimize the electronic environment of nickel-based active centers, enhance the formation of oxidized Ni species, and thus improve the oxygen evolution reaction kinetics.
[0124] 2. Improved structural stability: The composite layer formed by synergistic modification is more dense and uniform, and can maintain the integrity of the interface during long-term electrolysis. In contrast, layered modification is prone to problems such as interface delamination or uneven active layer, which leads to performance degradation.
[0125] Summarize:
[0126] This invention constructs CDs-PO4 3- The composite interface layer enables interface modulation of Ni-based electrodes, significantly enhancing OER activity in alkaline seawater while effectively inhibiting Cl-. - and Br - The poisoning effect of this technology stems from the synergistic effect of carbon quantum dots and phosphate groups in terms of structural stability, electron transport, and surface chemical regulation.
[0127] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A method for preparing a phosphate-modified carbon quantum dot nickel-based catalyst, characterized in that, Includes the following steps: Citric acid and urea were mixed in water to obtain a carbon quantum dot precursor solution; The carbon quantum dot precursor solution, phytic acid, and nickel substrate are mixed and reacted to obtain the phosphate-modified carbon quantum dot nickel-based catalyst.
2. The preparation method according to claim 1, characterized in that, The molar ratio of citric acid to urea is 1:
6.
3. The preparation method according to claim 1, characterized in that, The concentration of urea in the carbon quantum dot precursor solution is 0-4 mol / L and is not 0.
4. The preparation method according to claim 1, characterized in that, The ratio of carbon quantum dot precursor solution to phytic acid is 30 mL: 1.1 g.
5. The preparation method according to claim 1, characterized in that, The reaction was carried out at a temperature of 160-220℃ for 5 hours.
6. The preparation method according to claim 1, characterized in that, The nickel substrate is nickel foam, Ni(OH)2, Ni mesh, or Raney nickel.
7. A phosphate-modified carbon quantum dot nickel-based catalyst obtained by the preparation method according to any one of claims 1-6.
8. The application of the phosphate-modified carbon quantum dot nickel-based catalyst of claim 7 in the field of water electrolysis for hydrogen production.
9. The application according to claim 8, characterized in that, The application is in the electrolysis of Br-containing... - and Cl - Applications in the field of alkaline seawater hydrogen production.
10. An electrolytic method containing Br - and Cl - A method for producing hydrogen from alkaline seawater, characterized in that, Using the phosphate-modified carbon quantum dot nickel-based catalyst of claim 7 as the anode material, in a Br-containing environment... - and Cl - The oxygen evolution reaction takes place in alkaline seawater.