NiMo-LDH (layered double hydroxide) electrocatalytic material loaded on foamed nickel as well as preparation method and application of NiMo-LDH electrocatalytic material
By loading NiMo-LDH electrocatalyst material onto nickel foam, the problem of kinetic lag in the urea oxidation reaction was solved, achieving a highly efficient urea oxidation reaction, reducing energy consumption and improving energy conversion efficiency.
Patent Information
- Application Number
- CN202511076875.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-01
- Publication Date
- 2025-10-31
AI Technical Summary
The urea oxidation reaction (UOR) in hydrogen production involves a complex six-electron transfer mechanism that leads to kinetic stagnation. New electrocatalyst systems are needed to overcome the reaction energy barrier, as existing materials are insufficient in terms of energy conversion efficiency and stability.
A method for preparing NiMo-LDH electrocatalytic materials supported on nickel foam was adopted, which synthesized NiMo-LDH/NF via a one-step hydrothermal method. This simplified the preparation process, used inexpensive and readily available raw materials, constructed a highly catalytically active and stable conductive network, and optimized electron transport characteristics.
In 1M KOH and 0.33M urea solutions, a current density of 10mA cm-2 can be obtained with only 1.330V, and a current density of 100 mA cm-2 can be achieved with only 1.356V, which significantly reduces the overpotential threshold and improves the energy conversion efficiency.
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Figure CN120866852A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrochemical technology, and particularly relates to NiMo-LDH electrocatalytic materials supported on nickel foam, their preparation methods, and applications. Background Technology
[0002] Urea oxidation (UOR), as a powerful alternative to oxygen evolution reaction (OER) in hydrogen production, has attracted widespread attention. Utilizing urea-rich wastewater (such as urine) to generate hydrogen offers significant economic and environmental advantages. On one hand, compared to OER, UOR has a lower operating energy barrier (0.37V vs. 1.23V), which significantly reduces energy consumption in hydrogen production. On the other hand, direct electrolysis of urine not only facilitates efficient wastewater management but also enables a sustainable "wastewater-to-green-hydrogen" process, avoiding complex and carbon-intensive wastewater purification steps. However, its industrial application faces a key bottleneck: the complex six-electron transfer mechanism involved in UOR leads to kinetic stagnation, requiring novel electrocatalyst systems to overcome the reaction energy barrier. Therefore, it is necessary to construct functional materials with high catalytic activity, stable conductive networks, and optimized electron transport characteristics to reduce the overpotential threshold and improve energy conversion efficiency. Summary of the Invention
[0003] The purpose of this invention is to provide a method for preparing NiMo-LDH electrocatalytic materials supported on nickel foam, aiming to solve the problems mentioned in the background art.
[0004] The present invention is implemented as follows: a method for preparing NiMo-LDH electrocatalytic material supported on nickel foam, comprising the following steps:
[0005] The nickel foam was ultrasonically treated sequentially with nitric acid, ethanol and deionized water.
[0006] Nickel nitrate hexahydrate, urea, sodium molybdate dihydrate and sodium dodecyl sulfonate were added to deionized water. The stirred mixture was then transferred to a polytetrafluoroethylene reactor, where the treated nickel foam was placed and subjected to a hydrothermal reaction.
[0007] After the reaction is complete, the reactor is allowed to cool naturally to room temperature. The reacted nickel foam is then removed, rinsed, and dried to obtain the nickel foam-supported NiMo-LDH electrocatalytic material.
[0008] Preferably, in the step of ultrasonically treating the nickel foam sequentially with nitric acid, ethanol and deionized water, the concentration of the nitric acid is 1M.
[0009] Preferably, the molar ratio of nickel nitrate hexahydrate to sodium molybdate dihydrate is 1-2:1-2.
[0010] Preferably, the hydrothermal reaction is carried out at a temperature of 80-120°C for 9-15 hours.
[0011] Another objective of this invention is to provide a NiMo-LDH electrocatalytic material supported on nickel foam, which is prepared using the above-described preparation method.
[0012] Another objective of this invention is to provide an application of NiMo-LDH electrocatalytic material supported on nickel foam in the electrocatalytic oxidation of urea.
[0013] Preferably, the method includes the following steps: placing the NiMo-LDH electrocatalytic material supported on the nickel foam as the working electrode in an electrochemical reaction cell, with Hg / HgO as the reference electrode, a platinum sheet as the counter electrode, and a mixed solution of KOH solution and urea solution as the electrolyte, and driving the urea oxidation reaction under the condition of energization.
[0014] Preferably, the potential applied during energization is 1.25-1.45V relative to the RHE electrode.
[0015] The method for preparing NiMo-LDH electrocatalytic material supported on nickel foam provided in this invention uses readily available raw materials to synthesize NiMo-LDH / NF (i.e. NiMo-LDH supported on nickel foam) in one step via hydrothermal method. The preparation method is simple, the required equipment and raw materials are abundant and inexpensive, easy to obtain and easy to repeat, easy to control costs in industrial production, suitable for large-scale production, and the material quality is stable.
[0016] The prepared NiMo-LDH electrocatalyst material supported on nickel foam can be used as a working electrode in the urea oxidation reaction. In 1M KOH and 0.33M urea solution, only 1.330V (relative to the standard hydrogen electrode) is required to obtain 10mA cm⁻¹. -2 The current density is used to drive the UOR, and it reaches 100 mA cm⁻¹ -2 The current density required is only 1.356V (relative to the standard hydrogen electrode). Attached Figure Description
[0017] Figure 1 The XRD characterization images are of the samples prepared in Examples 1-3 of this invention;
[0018] Figure 2 The XPS full spectrum of the sample prepared in Example 1 of this invention;
[0019] Figure 3 This is a fine Ni 2p spectrum of the sample prepared in Example 1 of the present invention;
[0020] Figure 4The fine Mo 3d spectrum of the sample prepared in Example 1 of this invention;
[0021] Figure 5 The fine O 1s spectrum of the sample prepared in Example 1 of this invention;
[0022] Figure 6 The cyclic voltammetry curve of the sample prepared in Example 1 of this invention;
[0023] Figure 7 The electric double-layer capacitance value of the sample prepared in Example 1 of this invention;
[0024] Figure 8 This is a comparison chart of the LSV curves of the samples prepared in Examples 1-7 of this invention. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0026] A NiMo-LDH electrocatalytic material supported on nickel foam is prepared by the following steps:
[0027] S1. Cut the nickel foam NF into rectangles of 2×3cm. Sonicate the cut nickel foam NF in 1M HNO3 for 10min, in ethanol for 10min, and in deionized water for 10min in sequence.
[0028] S2. Dissolve 0.32-0.65g nickel nitrate hexahydrate, 0.74g urea, 0.27-0.54g sodium molybdate dihydrate and 0.20g sodium dodecyl sulfonate in 30mL deionized water. Transfer the stirred mixture to a 50mL polytetrafluoroethylene reactor, add the treated nickel foam, and carry out a hydrothermal reaction.
[0029] S3. After the reaction is complete, let the reactor cool naturally to room temperature, take out the reacted nickel foam and rinse it with deionized water and ethanol, then place it in a drying oven at 60°C for 6 hours to obtain NiMo-LDH / NF.
[0030] The application of the above-mentioned NiMo-LDH / NF as an electrocatalytic material in the electrocatalytic oxidation of urea specifically includes the following steps: setting up a single electrolytic cell as the electrochemical reaction cell, adopting a three-electrode system, using NiMo-LDH / NF as the working electrode, Hg / HgO as the reference electrode, a platinum sheet as the counter electrode, and 1M KOH solution and 0.33M urea solution as the electrolyte. The potential applied when energizing is 1.25-1.45V compared to the RHE electrode.
[0031] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.
[0032] Example 1: A NiMo-LDH electrocatalytic material supported on nickel foam, the specific preparation method of which is as follows:
[0033] The cut nickel foam was treated sequentially with nitric acid, ethanol, and deionized water. The raw materials selected were analytical grade nickel nitrate hexahydrate (0.32 g), urea (0.74 g), sodium molybdate dihydrate (0.27 g), and sodium dodecyl sulfonate (0.20 g), dissolved in 30 mL of deionized water. The stirred mixture was transferred to a polytetrafluoroethylene (PTFE) liner, and the treated nickel foam was placed inside. The reaction was carried out at 100°C under hydrothermal conditions for 12 h. After the reaction vessel cooled to room temperature, the nickel foam in the reaction vessel was rinsed with deionized water and ethanol. The mixture was then dried in a vacuum drying oven at 60°C for 6 h to obtain the NiMo-LDH electrocatalytic material supported on the nickel foam.
[0034] Example 2: A NiMo-LDH-80℃ electrocatalytic material supported on nickel foam, the specific preparation method of which is as follows:
[0035] The cut nickel foam was treated sequentially with nitric acid, ethanol, and deionized water. The raw materials selected were analytical grade nickel nitrate hexahydrate (0.32 g), urea (0.74 g), sodium molybdate dihydrate (0.27 g), and sodium dodecyl sulfonate (0.20 g), dissolved in 30 mL of deionized water. The stirred mixture was transferred to a polytetrafluoroethylene (PTFE) liner, and the treated nickel foam was placed inside. The reaction was carried out at 80 °C under hydrothermal conditions for 12 h. After the reaction vessel cooled to room temperature, the nickel foam in the reaction vessel was rinsed with deionized water and ethanol. The mixture was then dried in a vacuum drying oven at 60 °C for 6 h to obtain the NiMo-LDH electrocatalytic material supported on the nickel foam.
[0036] Example 3: A NiMo-LDH-120℃ electrocatalytic material supported on nickel foam, the specific preparation method of which is as follows:
[0037] The cut nickel foam was treated sequentially with nitric acid, ethanol, and deionized water. The raw materials selected were analytical grade nickel nitrate hexahydrate (0.32 g), urea (0.74 g), sodium molybdate dihydrate (0.27 g), and sodium dodecyl sulfonate (0.20 g), dissolved in 30 mL of deionized water. The stirred mixture was transferred to a polytetrafluoroethylene (PTFE) liner, and the treated nickel foam was placed inside. The reaction was carried out at 120 °C under hydrothermal conditions for 12 h. After the reaction vessel cooled to room temperature, the nickel foam in the reaction vessel was rinsed with deionized water and ethanol. The mixture was then dried in a vacuum drying oven at 60 °C for 6 h to obtain the nickel foam-supported NiMo-LDH electrocatalytic material.
[0038] Example 4: A NiMo-LDH-9h electrocatalytic material supported on nickel foam, the specific preparation method of which is as follows:
[0039] The cut nickel foam was treated sequentially with nitric acid, ethanol, and deionized water. The raw materials selected were analytical grade nickel nitrate hexahydrate (0.32 g), urea (0.74 g), sodium molybdate dihydrate (0.27 g), and sodium dodecyl sulfonate (0.20 g), dissolved in 30 mL of deionized water. The stirred mixture was transferred to a polytetrafluoroethylene (PTFE) liner, and the treated nickel foam was placed inside. The reaction was carried out at 100°C under hydrothermal conditions for 9 h. After the reaction vessel cooled to room temperature, the nickel foam in the reaction vessel was rinsed with deionized water and ethanol. The mixture was then dried in a vacuum drying oven at 60°C for 6 h to obtain the NiMo-LDH electrocatalytic material supported on the nickel foam.
[0040] Example 5: A NiMo-LDH-15h electrocatalytic material supported on nickel foam, the specific preparation method of which is as follows:
[0041] The cut nickel foam was treated sequentially with nitric acid, ethanol, and deionized water. The raw materials selected were analytical grade nickel nitrate hexahydrate (0.32 g), urea (0.74 g), sodium molybdate dihydrate (0.27 g), and sodium dodecyl sulfonate (0.20 g), dissolved in 30 mL of deionized water. The stirred mixture was transferred to a polytetrafluoroethylene (PTFE) liner, and the treated nickel foam was placed inside. The reaction was carried out at 100°C under hydrothermal conditions for 15 h. After the reaction vessel cooled to room temperature, the nickel foam in the reaction vessel was rinsed with deionized water and ethanol. The mixture was then dried in a vacuum drying oven at 60°C for 6 h to obtain the nickel foam-supported NiMo-LDH electrocatalytic material.
[0042] Example 6: A Ni2Mo1-LDH electrocatalytic material supported on nickel foam, the specific preparation method of which is as follows:
[0043] The cut nickel foam was treated sequentially with nitric acid, ethanol, and deionized water. The raw materials selected were analytical grade nickel nitrate hexahydrate (0.65 g), urea (0.74 g), sodium molybdate dihydrate (0.27 g), and sodium dodecyl sulfonate (0.20 g), dissolved in 30 mL of deionized water. The stirred mixture was transferred to a polytetrafluoroethylene (PTFE) liner, and the treated nickel foam was placed inside. The reaction was carried out at 100°C under hydrothermal conditions for 12 h. After the reaction vessel cooled to room temperature, the nickel foam in the reaction vessel was rinsed with deionized water and ethanol. The mixture was then dried in a vacuum drying oven at 60°C for 6 h to obtain the NiMo-LDH electrocatalytic material supported on the nickel foam.
[0044] Example 7: A Ni1Mo2-LDH electrocatalytic material supported on nickel foam, the specific preparation method of which is as follows:
[0045] The cut nickel foam was treated sequentially with nitric acid, ethanol, and deionized water. The raw materials selected were analytical grade nickel nitrate hexahydrate (0.32 g), urea (0.74 g), sodium molybdate dihydrate (0.54 g), and sodium dodecyl sulfonate (0.20 g), dissolved in 30 mL of deionized water. The stirred mixture was transferred to a polytetrafluoroethylene (PTFE) liner, and the treated nickel foam was placed inside. The reaction was carried out at 100°C under hydrothermal conditions for 12 h. After the reaction vessel cooled to room temperature, the nickel foam in the reaction vessel was rinsed with deionized water and ethanol. The mixture was then dried in a vacuum drying oven at 60°C for 6 h to obtain the nickel foam-supported NiMo-LDH electrocatalytic material.
[0046] Performance testing:
[0047] The NiMo-LDH / NF samples prepared in Examples 1-3 were analyzed, and the XRD spectra were obtained as follows: Figure 1 As shown, the XPS full spectrum is as follows: Figure 2 As shown, the fine spectrum of Ni 2p is as follows: Figure 3 As shown, the fine spectrum of Mo 3d is as follows: Figure 4 As shown, the fine spectrum of O 1s is as follows Figure 5 As shown;
[0048] The samples prepared in Example 1 were subjected to cyclic voltammetry tests, and the double-layer capacitance was calculated. Their cyclic voltammetric curves in a KOH and urea mixed electrolyte are shown below. Figure 6 As shown, the results of the double-layer capacitance values are as follows: Figure 7 As shown.
[0049] The samples prepared in Examples 1-7 were used as electrocatalytic materials to test their role in electrocatalytic urea oxidation-assisted overall water splitting. The specific operation was as follows:
[0050] Using a mixed solution of 1M potassium hydroxide and 0.33M urea as the electrolyte, the samples prepared in the seven examples were used as working electrodes, with a platinum sheet as the counter electrode and a mercury / mercury oxide electrode as the reference electrode. The potential was controlled at 0.2-0.6V relative to the mercury / mercury oxide electrode. The results were obtained by testing with an electrochemical workstation. Figure 8 The LSV curve shown is based on Figure 8 It can be seen that the material prepared in the embodiments of the present invention requires only 1.330V (relative to the standard hydrogen electrode) in 1M KOH and 0.33M urea solution to obtain 10mA cm⁻¹. -2 The current density is used to drive the UOR, and it reaches 100 mA cm⁻¹ -2 The current density required is only 1.356V (relative to the standard hydrogen electrode).
[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing NiMo-LDH electrocatalytic material supported on nickel foam, characterized in that, Includes the following steps: The nickel foam was ultrasonically treated sequentially with nitric acid, ethanol and deionized water. Nickel nitrate hexahydrate, urea, sodium molybdate dihydrate and sodium dodecyl sulfonate were added to deionized water. The stirred mixture was then transferred to a polytetrafluoroethylene reactor, where the treated nickel foam was placed and subjected to a hydrothermal reaction. After the reaction is complete, the reactor is allowed to cool naturally to room temperature. The reacted nickel foam is then removed, rinsed, and dried to obtain the nickel foam-supported NiMo-LDH electrocatalytic material.
2. The method for preparing NiMo-LDH electrocatalytic material supported on nickel foam according to claim 1, characterized in that, In the step of sequentially ultrasonically treating the nickel foam with nitric acid, ethanol, and deionized water, the concentration of the nitric acid is 1M.
3. The method for preparing NiMo-LDH electrocatalytic material supported on nickel foam according to claim 1, characterized in that, The molar ratio of nickel nitrate hexahydrate to sodium molybdate dihydrate is 1-2:1-2.
4. The method for preparing NiMo-LDH electrocatalytic material supported on nickel foam according to claim 1, characterized in that, The hydrothermal reaction is carried out at a temperature of 80-120℃ for 9-15 hours.
5. A NiMo-LDH electrocatalytic material supported on nickel foam, characterized in that, It is prepared using the preparation method described in any one of claims 1-5.
6. The application of the NiMo-LDH electrocatalytic material supported on nickel foam as described in claim 5 in the electrocatalytic oxidation of urea.
7. The application according to claim 6, characterized in that, Includes the following steps: The NiMo-LDH electrocatalytic material supported on the nickel foam was placed in an electrochemical reaction cell as the working electrode. The reference electrode was Hg / HgO, the counter electrode was a platinum sheet, and the electrolyte was a mixed solution of KOH solution and urea solution. The urea oxidation reaction was driven under the condition of energization.
8. The application according to claim 7, characterized in that, The potential applied during energization is 1.25-1.45V relative to the RHE electrode.