Electrolyzed water anode material and preparation method and application thereof
By constructing a heterojunction catalyst of NiFe-LDHs and TiO2 quantum dots on a nickel foam substrate, the problems of scarce precious metal catalyst resources and low electron conduction efficiency of NiFe-LDHs were solved, a low-cost, highly stable water electrolysis anode material was achieved, and the redox reaction performance was improved.
Patent Information
- Application Number
- CN202510696317.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-28
- Publication Date
- 2025-09-16
AI Technical Summary
Existing precious metal catalysts such as RuO2 and IrO2 are scarce, expensive and unstable, which limits the large-scale application of water electrolysis hydrogen production technology. NiFe-LDHs layers are easily dissolved in a strong alkaline environment and have low electron conduction efficiency, resulting in a decline in catalytic performance.
NiFe-LDHs and TiO2 quantum dot heterojunction catalysts were constructed on a nickel foam substrate through an electrodeposition-hydrothermal composite process. The quantum confinement effect and interfacial charge rearrangement of TiO2 quantum dots were utilized to optimize electron transport and active site density, thereby forming a heterojunction interface.
The catalytic activity and stability of the anode material for water electrolysis are improved, the cost is reduced, efficient redox reaction is achieved, and the problems of poor conductivity and insufficient exposure of active sites in traditional catalysts are solved.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of catalytic materials, and in particular to an anode material for electrolysis of water, a preparation method thereof, and an application thereof. Background Art
[0002] With the rapid development of the hydrogen economy, water electrolysis has become a core approach for large-scale production of green hydrogen due to its mild reaction conditions and high product purity. However, the sluggish kinetics of the oxygen evolution reaction at the anode require a high overpotential drive, which seriously restricts the overall energy conversion efficiency. Currently, commercial OER catalysts mainly rely on precious metal materials such as RuO2 and IrO2. Although they have excellent catalytic activity, they are scarce in resources, expensive (accounting for more than 80% of the total cost of the electrolysis system), and have problems with long-term stability, making it difficult to meet the needs of large-scale applications.
[0003] In this context, transition metal-based catalysts (such as NiFe layered double hydroxides) have attracted much attention due to their high earth abundance and outstanding catalytic activity. 2+ with Fe 3+ Due to the synergistic effect of the two, NiFe-LDHs exhibit high OER activity in alkaline media, but their intrinsic defects still significantly limit their practical applications. The layered structure of NiFe-LDHs is mainly hydroxide, and electron conduction relies on interlayer ion transitions, resulting in high resistance and hindering reaction kinetics. Secondly, in a strong alkaline environment, the layers of NiFe-LDHs are prone to dissolution or phase change (such as from hydroxide to oxide), resulting in the loss of active sites and the attenuation of catalytic performance. During long-term electrolysis, the nanosheets are prone to agglomeration or peeling, further reducing the catalytic life.
[0004] Doped TiO2 quantum dots (TiO2 QDs) can significantly improve the catalytic performance of transition metal compounds through the following mechanisms. The quantum confinement effect of TiO2 QDs can enhance carrier mobility, and its small size (2-10 nm) shortens the electron transport path, alleviating the intrinsic insulation problem of NiFe-LDHs. TiO2 QDs form a tight heterojunction interface with NiFe-LDHs, regulating the local electronic structure through interfacial charge rearrangement, and improving Ni 2+ / Fe 3+ In addition, the high specific surface area of quantum dots can expose more active sites and inhibit the aggregation and structural collapse of NiFe-LDH.
[0005] Although the introduction of TiO2 QDs has significant advantages, it is difficult to achieve strong interface coupling through simple physical mixing, and the semiconductor properties of TiO2 itself may limit the overall conductivity. Therefore, it is urgent to develop a composite strategy that synergistically optimizes quantum effects and interface engineering to fully realize the synergistic catalytic potential of NiFe-LDHs and TiO2 QDs.
[0006] The present invention uses an electrodeposition-hydrothermal composite process to in situ construct a NiFe-LDHs / TiO2QDs heterojunction catalyst on a nickel foam substrate, achieving efficient interfacial charge transfer and maximizing the active site density, providing a new idea for the development of low-cost, highly stable OER catalysts. Summary of the Invention
[0007] The present invention provides a water electrolysis anode material, a preparation method, and an application thereof. The heterojunction water electrolysis anode material prepared by this method increases the reactive sites and effectively improves the electrocatalytic hydrogen production performance of the single-component TiO2 / bimetallic layered double hydroxide.
[0008] In order to achieve the above object, the present invention provides the following technical solutions:
[0009] The present invention provides an electrolytic water anode material, which uses nickel foam as a substrate, wherein NiFe layered double hydroxide is loaded on the nickel foam, TiO2 quantum dots are compounded on the surface of the NiFe layered double hydroxide, and the composite interface between the NiFe layered double hydroxide and the TiO2 quantum dots has a heterojunction structure.
[0010] The present invention utilizes TiO2 QDs as a highly efficient anode catalyst for water electrolysis, leveraging their advantages of small size, quantum effect, and short electron transport paths. This coupled quantum effect ensures excellent conductivity. The abundant contact surface between TiO2 QDs and the bimetallic layered hydroxide forms a sufficient heterogeneous interface, promoting efficient interfacial charge transfer and facilitating the hydrogen evolution reaction.
[0011] The present invention realizes multi-dimensional collaborative optimization from the mechanism level of oxygen evolution reaction by constructing a heterojunction interface between TiO2 quantum dots and NiFe-LDHs, breaking through the bottleneck of poor conductivity and insufficient exposure of active sites of traditional transition metal-based catalysts. In the four-electron transfer process of OER, the layered structure of NiFe-LDHs provides abundant alkaline adsorption sites, but its intrinsic insulation leads to low electron transfer efficiency, and the layer plate is prone to dissolution or phase change in a strong alkaline environment, resulting in loss of active sites. The present invention introduces TiO2 quantum dots and utilizes its quantum confinement effect to shorten the carrier migration path, limit electron transfer to the nanoscale, and significantly improve the interface charge transfer rate. At the same time, the surface oxygen vacancies of TiO2 quantum dots serve as highly active sites, which interact with the Ni of NiFe-LDHs.2+ / Fe 3+ The active centers form a synergistic effect, optimize the adsorption energy of oxygen intermediates (*OH, *O, *OOH), and reduce the energy barrier of the rate-determining step.
[0012] During the reaction, TiO2 quantum dots have good dispersion, large specific surface area, small size and narrow size distribution, so the number of active sites exposed on their surface increases, thereby improving catalytic activity; while the interlayer defects of LDHs stabilize the distribution of quantum dots through strong interfacial bonding, preventing agglomeration. This dynamic synergistic mechanism not only enhances the intrinsic activity of the catalyst, but also gives it excellent structural stability, solving the problem of activity decay of traditional LDHs in long-term electrolysis. The heterogeneous structure constructed by the electrodeposition-hydrothermal composite process achieves the synergistic optimization of active site density, charge transfer efficiency and mechanical stability, providing an innovative solution for the development of low-cost, highly durable non-precious metal OER catalysts.
[0013] The present invention provides a method for preparing an anode material for electrolysis of water, comprising:
[0014] S1. Using nickel source, iron source, and urea as raw materials, NiFe layered double hydroxides were grown on the surface of nickel foam by electrodeposition to obtain NiFe-LDHs / NF;
[0015] S2. The titanium source, urea and S1 NiFe-LDHs / NF are ultrasonically mixed in a solvent to obtain a mixture, and then the mixture undergoes a hydrothermal reaction to grow TiO2 quantum dots on the surface of NiFe-LDHs / NF to obtain a water electrolysis anode material.
[0016] Preferably, in S1, the nickel foam has a thickness of 0.5-1 mm, a pore density of 100-130 PPI, and a pore diameter of 0.1-0.3 mm.
[0017] Preferably, in S1, the nickel source includes nickel nitrate and / or nickel chloride, the iron source includes ferric nitrate and / or ferric chloride, and the molar ratio between the nickel in the nickel source and the iron in the iron source is (1-3):1.
[0018] Preferably, the concentration of the nickel source is 0.1 to 0.3 M.
[0019] Preferably, the concentration of the iron source is 0.05-0.15M.
[0020] Preferably, in S1, the concentration of urea is 0.5-1.5M.
[0021] Preferably, in S1, the conditions of the electrodeposition method are: voltage of 1.5-2.5 V, deposition reaction at 50-80° C. for 1-3 h.
[0022] Preferably, in S2, the titanium source includes titanium sulfate, and the molar ratio between the titanium in the titanium source and the nickel and iron in the NiFe-LDHs / NF is 1:(1-20).
[0023] Preferably, in S2, the temperature of the hydrothermal reaction is 150-200° C., and the time is 3-6 hours.
[0024] Preferably, in S2, the solvent is deionized water.
[0025] An OER catalyst comprises the water electrolysis anode material provided by the present invention.
[0026] Therefore, the present invention has the following beneficial effects:
[0027] (1) The present invention provides a new composite electrocatalytic hydrogen evolution catalyst for constructing a heterojunction interface of TiO2 quantum dots and NiFe-LDHs and a preparation method thereof, which improves the active site density of transition metal compound catalysts by utilizing the quantum effect of TiO2 quantum dots with small size and large active area, and synergistically enhances the oxygen evolution performance.
[0028] (2) The present invention uses low-cost raw materials such as titanium sulfate, nickel salts, and iron salts, combined with mature electrodeposition and hydrothermal processes, and has good scalability. This strategy can also be extended to TiO2 QDs / NiFe-LDHs / NF and CeO2 QDs / NiFe-LDHs / NF systems, providing a universal template for the development of multi-element high-efficiency catalysts. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 A comparison chart of catalytic performance. DETAILED DESCRIPTION
[0030] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below generally represent only a portion of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.
[0031] [Example]
[0032] Example 1 TiO2 QDs / NiFe-LDHs / NF
[0033] (1) Preparation of NiFe-LDHs / NF: nickel nitrate hexahydrate (Ni(NO3)2·6H2O, 0.3M), ferric nitrate nonahydrate (Fe(NO3)3·9H2O, 0.1M), urea (CH4N2O, 1M), and deionized water as solvent were used as electrolyte. At room temperature, a nickel foam current collector (commercially available, thickness 1 mm, surface density 550, pore size 0.2 mm, pore density 110, purity above 99.9%, size 1×2 cm) was used. 2 ) was sonicated with 1M HCl solution for 1 minute to remove any possible oxidation layer. Then, it was sonicated with ethanol and deionized water for 1 minute and 5 minutes, respectively, to remove organic contaminants and water-soluble impurities, obtaining pretreated nickel foam (NF). Electrodeposition was performed in an 80°C water bath at a constant voltage of 2V for 2 hours using the pretreated nickel foam as the working electrode, a platinum sheet as the counter electrode, and a saturated calomel electrode as the reference electrode. After electrodeposition, the sample was rinsed with deionized water and dried in a vacuum oven at 60°C.
[0034] (2) Preparation of TiO2 QDs / NiFe-LDHs / NF: Weigh 0.24 g (1 mmol) of anhydrous titanium sulfate, 0.0063 g (0.1 mmol) of urea and a 1×2 cm 2 NiFe-LDHs / NF was dissolved in 70 mL of deionized water (molar ratio, (Ni+Fe):Ti=4:1). The solution was then sonicated for 15 minutes. The resulting mixture was hydrothermally treated at 170°C for 4 hours in a 100 mL Teflon-lined stainless steel autoclave. The final product was then washed several times with deionized water.
[0035] Comparative Example 1 NiFe-LDHs / NF composite electrode
[0036] Preparation of NiFe-LDHs / NF: nickel nitrate hexahydrate (Ni(NO3)2·6H2O, 0.3M), ferric nitrate nonahydrate (Fe(NO3)3·9H2O, 0.1M), urea (CH4N2O, 1M), and deionized water as solvent were used to prepare the electrolyte; pretreated nickel foam was used as the working electrode, platinum sheet as the counter electrode, and saturated calomel electrode as the reference electrode. The electrodes were electrodeposited at a constant voltage of 2V in a water bath at 80°C for 2 hours. After electrodeposition, the electrodes were rinsed with deionized water and dried in a vacuum at 60°C.
[0037] Comparative Example 2TiO2 QDs / NF composite electrode
[0038] Preparation of TiO2 QDs / NF: 0.24 g (1 mmol) of anhydrous titanium sulfate, 0.0063 g (0.1 mmol) of urea and 1 × 2 cm 2The pretreated nickel foam was dissolved in 35 mL of deionized water. The solution was then sonicated for 15 minutes. The resulting mixture was hydrothermally treated at 170°C for 4 hours in a 50 mL Teflon-lined stainless steel autoclave. The final product was then washed several times with deionized water.
[0039] Comparative Example 3TiO2 / NiFe-LDHs / NF composite electrode
[0040] (1) Preparation of NiFe-LDHs / NF: nickel nitrate hexahydrate (Ni(NO3)2·6H2O, 0.3M), ferric nitrate nonahydrate (Fe(NO3)3·9H2O, 0.1M), urea (CH4N2O, 1M), and deionized water as solvent were used to prepare the electrolyte; pretreated nickel foam was used as the working electrode, platinum sheet was used as the counter electrode, and saturated calomel electrode was used as the reference electrode. Electrodeposition was performed at a constant voltage of 2V in a water bath at 80℃ for 2 h. After electrodeposition, the cells were rinsed with deionized water and dried in a vacuum at 60℃.
[0041] (2) Preparation of TiO2 / NiFe-LDHs / NF: Titanium tetrachloride (TiCl4) was dissolved in deionized water to prepare a 0.1 M solution. A small amount of sodium hydroxide (NaOH) was added to adjust the pH to alkaline (pH = 10-12) to form a TiO2 sol. NiFe-LDH / NF was immersed in the TiO2 sol and hydrothermally reacted at 170°C for 4 hours. After cooling, the solution was washed with deionized water and dried to obtain a TiO2 / NiFe-LDHs / NF composite electrode.
[0042] Comparative Example 4: NiFe-LDHs / TiO2 QDs / NF
[0043] (1) Preparation of TiO2 QDs / NF: Weigh 0.24 g (1 mmol) of anhydrous titanium sulfate, 0.0063 g (0.1 mmol) of urea and a 1 × 2 cm 2 The NiFe-LDH / NF was dissolved in 35 mL of deionized water. The solution was then sonicated for 15 minutes. The resulting mixture was hydrothermally treated at 170°C for 4 hours in a 50 mL Teflon-lined stainless steel autoclave. The final product was washed several times with deionized water.
[0044] (2) Preparation of NiFe-LDHs / TiO2QDs / NF: Nickel nitrate hexahydrate (Ni(NO3)2·6H2O, 0.3M), ferric nitrate nonahydrate (Fe(NO3)3·9H2O, 0.1M), urea (CH4N2O, 1M), and deionized water as solvent were used to prepare the electrolyte; TiO2 QDs / NF was used as the working electrode, platinum sheet as the counter electrode, and saturated calomel electrode as the reference electrode. Electrodeposition was performed at a constant voltage of 2V in a water bath at 80℃ for 2 hours. After electrodeposition, the samples were rinsed with deionized water and dried in a vacuum at 60℃.
[0045]
Performance test
[0046] The final products obtained in Example 1 and Comparative Examples 1 to 4 were tested for performance, and the results were as follows: Figure 1 shown.
[0047] TiO2QDs / NiFe-LDHs / NF composite electrode (Example 1) was driven at 100 mA / cm in 1 M KOH solution. 2 The overpotential is as low as 260mV at the current density, showing an electrocatalytic performance significantly better than other comparative examples, reflecting that the single catalytic activity of TiO2 QDs / NF material (Comparative Example 2) and NiFe-LDHs / NF material (Comparative Example 1) is limited and insufficient to compare with the TiO2QDs / NiFe-LDHs / NF composite material. This performance improvement is due to the interface charge rearrangement between NiFe-LDHs and TiO2 quantum dots; NiFe-LDHs nanosheets provide high-density active sites, while TiO2 quantum dots shorten the carrier migration path through the quantum confinement effect, and the heterojunction interface formed by the two further promotes electron transfer efficiency. However, it is difficult to achieve efficient charge separation for NiFe-LDHs / NF or TiO2QDs / NF composite materials alone due to the lack of effective interface coupling.
[0048] The TiO2 / NiFe-LDHs / NF composite electrode (Comparative Example 3) combines two materials, but uses TiO2 in a non-quantum dot form. As can be seen from the figure, its performance is still significantly lower than that of Example 1. This is because the size effect of the TiO2 quantum dots provides more active sites and a larger specific surface area, thereby improving catalytic efficiency.
[0049] NiFe-LDHs / TiO2QDs / NF (Comparative Example 4) attempts to change the loading order of the materials, first preparing TiO2QDs / NF, and then electrodepositing NiFe-LDHs. However, its performance is only better than that of TiO2QDs / NF material (Comparative Example 2), 100mA / cm 2 The overpotential is as high as 438mV at this current density. This indicates that the stacking order of the materials has a significant impact on the final performance. This is because the conductivity of TiO2 QDs is inherently poor, and the subsequent electrodeposition of NiFe-LDHs greatly reduces the electron transport effect, which in turn reduces the performance.
[0050] In summary, Example 1 achieved a synergistic effect between TiO2QDs and NiFe-LDHs through reasonable material composition design and preparation process optimization, creating an interface structure that is more conducive to electron transport and reactant diffusion, thereby exhibiting optimal electrocatalytic performance. The heterojunction design of quantum dots and layered double hydroxides can simultaneously solve the bottleneck problems of poor conductivity and insufficient exposure of active sites in traditional transition metal-based catalysts, providing an important technical path for the development of low-cost, high-stability anode catalysts for water electrolysis.
Claims
1. A water electrolysis anode material, characterized in that: Nickel foam is used as a substrate, NiFe layered double hydroxide is loaded on the nickel foam, TiO2 quantum dots are compounded on the surface of the NiFe layered double hydroxide, and the composite interface of the NiFe layered double hydroxide and the TiO2 quantum dots has a heterojunction structure.
2. A method for preparing the anode material for electrolysis of water according to claim 1, characterized in that: include: S1. Using nickel source, iron source, and urea as raw materials, NiFe layered double hydroxides were grown on the surface of nickel foam by electrodeposition to obtain NiFe-LDHs / NF; S2. The titanium source, urea and S1 NiFe-LDHs / NF are ultrasonically mixed in a solvent to obtain a mixture, and then the mixture undergoes a hydrothermal reaction to grow TiO2 quantum dots on the surface of NiFe-LDHs / NF to obtain a water electrolysis anode material.
3. The preparation method according to claim 2, wherein In S1, the thickness of the nickel foam is 0.5-1 mm, the pore density is 100-130 PPI, and the pore diameter is 0.1-0.3 mm.
4. The preparation method according to claim 2, wherein In S1, the nickel source includes nickel nitrate and / or nickel chloride, the iron source includes ferric nitrate and / or ferric chloride, and the molar ratio between the nickel in the nickel source and the iron in the iron source is (1-3):
1.
5. The preparation method according to claim 2 or 4, characterized in that In S1, the concentration of urea is 0.5-1.5M.
6. The preparation method according to claim 2, wherein In S1, the conditions of the electrodeposition method are: voltage of 1.5 to 2.5 V, deposition reaction at 50 to 80° C. for 1 to 3 hours.
7. The preparation method according to claim 2, wherein In S2, the titanium source includes titanium sulfate, and the molar ratio between the titanium in the titanium source and the nickel and iron in the NiFe-LDHs / NF is 1:(1-20).
8. The preparation method according to claim 2, wherein In S2, the temperature of the hydrothermal reaction is 150-200° C., and the time is 3-6 hours.
9. The preparation method according to claim 2, wherein In S2, the solvent is deionized water.
10. An OER catalyst, characterized in that The invention comprises the water electrolysis anode material as claimed in claim 1 or the water electrolysis anode material prepared by the preparation method as claimed in any one of claims 2 to 9.