Process for the preparation of high performance nickel platinum catalytic material and applications and methods of use

Abstract

The application discloses a preparation method and application of high-performance nickel-platinum catalytic material and a use method, wherein the nickel foam is immersed into a solution containing a certain amount of chloroplatinic acid, and a Ni-Pt composite electrode containing rich NiO on the surface is prepared through a simple one-step chemical corrosion method. The embedded NiO on the surface can effectively reduce a water decomposition energy barrier, the introduction of Pt forms a PtNi alloy with high HER activity with the nickel foam substrate, thereby greatly reducing the amount of Pt and ensuring the adsorption / desorption efficiency of H intermediates, the stable NiO nanoparticles on the surface can effectively avoid the formation of unstable amorphous oxide on the surface of the PtNi alloy, thereby greatly improving the catalytic stability, and finally, the NiO and the PtNi alloy synergistically improve the electrocatalytic efficiency.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical electrode materials technology, specifically relating to a method for preparing, applying, and using a high-performance nickel-platinum catalytic material. Background Technology

[0002] Hydrogen energy boasts advantages such as high energy density, high cleanliness, high conversion efficiency, and abundant reserves, and is gradually becoming one of the important carriers for energy transition and development in various countries. Based on the carbon emissions of the production process, hydrogen is classified into three types: "gray hydrogen," "blue hydrogen," and "green hydrogen." Among these, hydrogen production through water electrolysis using renewable energy power generation, which involves zero carbon emissions and efficiently produces high-purity hydrogen, is the most promising method for "green hydrogen" production.

[0003] The electrolysis of water consists of two half-reactions: the hydrogen evolution reaction (HER) on the cathode side and the oxygen evolution reaction (OER) on the anode side. It is well known that the HER in alkaline media involves the Volmer step (H₂O + e⁻) due to the high water dissociation energy barrier. - →OH - +H ads The activity of hydrogen evolution reaction (HER) under alkaline conditions is much lower than that under acidic conditions. Therefore, how to select and synthesize highly active catalysts for HER under alkaline conditions to achieve efficient hydrogen production has become a key issue. According to the classic volcano diagram, the noble metal platinum and its derivatives have suitable hydrogen adsorption / desorption Gibbs free energies. However, the scarcity of platinum leads to its high price, resulting in high costs for hydrogen production through water electrolysis, which seriously hinders the rapid development of a hydrogen energy society. Therefore, the research focus has shifted to how to maintain or improve HER activity while reducing platinum loading.

[0004] Currently, alloying non-precious metals with precious metals has become one of the best options, and more and more research on platinum group alloys is emerging in the field of nanocatalysis. Among them, introducing more active sites through surface modification has become an important means to improve their HER activity. However, most surface modification methods, such as electrodeposition, hydrothermal treatment, and sintering, require additional energy and have complex processes.

[0005] Therefore, in order to solve the above problems, this paper proposes a method for preparing, applying and using high-performance nickel-platinum catalytic materials. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention presents a method for preparing, applying, and using high-performance nickel-platinum catalytic materials. A simple and controllable solution immersion corrosion method is employed to prepare a highly active and stable alkaline HER catalytic electrode using low-cost foam metal materials. Simultaneously, while synthesizing highly active Pt-based alloys, in-situ oxidation of the 3D foam metal framework surface synthesizes metal oxide nanoparticles that facilitate accelerated water dissociation.

[0007] To achieve the above-mentioned technical effects, the present invention is implemented through the following technical solution: a method for preparing a high-performance nickel-platinum catalytic material, characterized by comprising the following steps:

[0008] Step 1: Pre-treat the nickel foam by immersing it in hydrochloric acid with a concentration of 5-7 mol / L, ultrasonically cleaning it for 8-12 minutes, and then rinsing it with deionized water for later use.

[0009] Step 2: Dissolve chloroplatinic acid (H2PtCl6·6H2O) in deionized water and stir to obtain a homogeneous solution with a concentration of 1-2 mmol / L and a pH of 1-3;

[0010] Step 3: Immerse the nickel foam processed in Step 1 in the solution obtained in Step 2 at a temperature of 15-30°C for 2-6 hours.

[0011] Furthermore, this includes the following steps:

[0012] Step 1: Pre-treat the nickel foam by immersing it in 6 mol / L hydrochloric acid, ultrasonically cleaning it for 10 minutes, and rinsing it multiple times with deionized water for later use.

[0013] Step 2: Dissolve chloroplatinic acid (H2PtCl6·6H2O) in deionized water and stir to obtain a homogeneous solution with a concentration of 1.5 mmol / L and a pH of 2;

[0014] Step 3: Immerse the nickel foam processed in Step 1 in the solution obtained in Step 2 at a temperature of 25°C for 4 hours.

[0015] Furthermore, in Step 1, the pretreatment of the nickel foam involves cutting 1mm thick nickel foam into 1cm*1cm squares and washing it with deionized water 3 to 5 times.

[0016] Furthermore, in Step 2, chloroplatinic acid (H2PtC) l6 The purity of ·6H2O is 98%, and the platinum content is 38.3%.

[0017] Another object of the present invention is to provide an application of a high-performance nickel-platinum catalyst, characterized in that the high-performance nickel-platinum catalyst is used as a working electrode in the electrolysis of water to produce hydrogen.

[0018] Another objective of this invention is to provide a method for using a high-performance nickel-platinum catalyst, characterized by: using a 1 mol / L KOH solution as the electrolyte, a three-electrode system with the prepared Ni-Pt catalyst as the working electrode, saturated Ag / AgCl as the reference electrode, and a graphite rod as the counter electrode.

[0019] The beneficial effects of this invention are:

[0020] This invention proposes a simple and controllable solution immersion corrosion method to prepare a highly active and stable alkaline HER catalytic electrode using low-cost foamed metal materials. Simultaneously, a stable layer of metal oxide nanoparticles is generated on the surface of the 3D foamed metal framework through one-step synthesis of a highly active Pt-based alloy. This not only accelerates the Vormer hydrolysis step in the hydrogen evolution reaction but also effectively avoids the formation of unstable amorphous oxides on the Pt-based alloy surface, significantly improving catalytic activity and durability. Under low Pt loading conditions, it exhibits intrinsic catalytic activity and long-term stability superior to most platinum-based materials. The preparation method is very simple, reducing catalyst production costs and promoting the rapid development of a hydrogen energy society. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of 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.

[0022] Figure 1 The XRD patterns are those of the Ni-Pt catalyst prepared in Example 1 of this invention and the Fe-Pt, Cu-Pt, Co-Pt and Zn-Pt catalysts prepared in Examples 2-5.

[0023] Figure 2 These are the FE-SEM and EDS spectra of the Ni-Pt catalyst prepared in Example 1 of this invention.

[0024] Figure 3 The image shows the Raman spectroscopy diagram of the Ni-Pt catalyst prepared in Example 1 of this invention.

[0025] Figure 4 This is a comparison chart of the electrocatalytic hydrogen evolution reaction (HER) activities of the Ni-Pt catalyst prepared in Example 1 of this invention and the Fe-Pt, Cu-Pt, Co-Pt and Zn-Pt catalysts prepared in Example 2.

[0026] Figure 5 This is a comparison chart of the electrocatalytic hydrogen evolution reaction (HER) activities of the Ni-Pt catalyst prepared in Example 1 of this invention, the pretreated porous nickel foam (NF), and the commercial catalyst.

[0027] Figure 6 This is a comparison diagram of the electrocatalytic hydrogen evolution reaction (HER) activities of the Ni-Pt catalysts prepared in Examples 1 and 3 of this invention;

[0028] Figure 7 This is a comparison diagram of the electrocatalytic hydrogen evolution reaction (HER) activities of the Ni-Pt catalysts prepared in Examples 1 and 4 of this invention;

[0029] Figure 8 This is a comparison diagram of the electrocatalytic hydrogen evolution reaction (HER) activities of the Ni-Pt catalysts prepared in Examples 1 and 5 of this invention;

[0030] Figure 9 This is a stability test diagram of the Ni-Pt catalyst prepared in Example 1 of the invention;

[0031] Figure 10 This is an atomic model diagram of the catalyst of this invention;

[0032] Figure 11 This is a graph showing the relationship between the changes in Pt and Ni content and the catalyst performance of this invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] A method for preparing a high-performance Ni-Pt catalytic material specifically includes the following preparation steps:

[0036] (1) Cut 1mm thick nickel foam into 1cm*1cm squares, put them into hydrochloric acid with a concentration of 6mol / L, and ultrasonically clean them for 10min to remove the oxide layer on their surface. After hydrochloric acid treatment, immediately rinse them with ultrapure water 3-5 times.

[0037] (2) Weigh 20 mg of chloroplatinic acid (H2PtCl6·6H2O) with a purity of 98% and a platinum content of 38.3% and dissolve it in 30 mL of ultrapure water. Stir for 10 min to obtain a uniform solution. Place the treated nickel foam into the solution and soak it at 25 °C for 4 hours. Name it Ni-Pt nanocatalyst.

[0038] (3) In 1M KOH electrolyte, the prepared Ni-Pt catalyst was used as the working electrode, saturated Ag / AgCl was used as the reference electrode, and a graphite rod was used as the counter electrode to test its electrochemical performance.

[0039] Example 2

[0040] The specific preparation steps in this embodiment are the same as those in Example 1 for the Ni-Pt catalyst, except that the foam metal is changed from nickel foam to copper foam, iron foam, zinc foam, and cobalt foam. The other steps are exactly the same, and they are named Cu-Pt, Fe-Pt, Zn-Pt, and Co-Pt, respectively.

[0041] Example 3

[0042] The specific preparation steps in this embodiment are the same as those in Example 1 for the Ni-Pt catalyst, except that the soaking temperature is changed to -5 and 35°C, and the rest of the steps are exactly the same.

[0043] Example 4

[0044] The specific preparation steps in this embodiment are the same as those in Example 1 for the Ni-Pt catalyst, except that the amount of chloroplatinic acid (H2PtCl6·6H2O) is changed to 5, 10, and 30 mg, respectively. All other steps are exactly the same.

[0045] Example 5

[0046] The specific preparation steps in this embodiment are the same as those in Example 1 for the Ni-Pt catalyst, except that the soaking time is changed to 1, 2, 6, 8, 10, or 12 hours. All other steps are exactly the same.

[0047] XRD pattern analysis

[0048] Figure 1The XRD patterns are those of the Ni-Pt catalyst disclosed in Example 1 and the Fe-Pt, Cu-Pt, Co-Pt, and Zn-Pt catalysts disclosed in Example 2. The Ni-Pt catalyst exhibits diffraction peaks at 2θ angles of 40.8°, 47.4°, 69.4°, and 84.1°, corresponding to the (111), (200), (220), and (311) crystal planes of the PtNi alloy (PDF#04-003-4660). A distinct diffraction peak appears at 37.1°, corresponding to the (111) crystal plane of NiO (PDF#04-001-9373). The diffraction peaks at 44.5°, 51.9°, and 76.5° are the (111), (200), and (220) crystal planes of elemental Ni, primarily originating from the nickel foam substrate (PDF#04-001-0091). This demonstrates that during the immersion corrosion process, the surface of the nickel foam interacts with Pt ions in the solution, resulting in the in-situ formation of a PtNi alloy phase and a NiO phase that facilitates water dissociation. Figure 1 It can be seen that all five catalysts exhibit obvious alloy peaks around 40°. Furthermore, in the Fe-Pt catalyst, the diffraction peak at 40.3° corresponds to the (111) crystal plane of the PtFe alloy (PDF#04-003-5272), while the diffraction peaks at 44.7°, 65.1°, 73.4°, and 82.5° correspond to the (110), (200), (220), and (211) crystal planes of elemental iron (PDF#04-002). -1061), originating from a foamed iron substrate; in the Cu-Pt catalyst, the diffraction peaks at 41.4° and 48.2° correspond to the (111) and (200) crystal planes of the PtCu alloy (PDF#04-004-8731), while the diffraction peaks at 43.3°, 50.4° and 74.1° are the (111), (200), (220) and (311) crystal planes of elemental copper (PDF#04-001-0092). Derived from a copper foam substrate; in the Co-Pt catalyst, the diffraction peaks at 33.4° and 41.7° correspond to the (100) and (101) crystal planes of the PtCo alloy (PDF#04-003-4871), while the diffraction peaks at 44.2°, 51.5° and 75.9° are the (111), (200) and (220) crystal planes of elemental cobalt (PDF#04-007-8519), originating from a cobalt foam substrate; in the Zn- In the Pt catalyst, the diffraction peaks at 33.4° and 41.7° correspond to the (100) and (101) crystal planes of the PtCo alloy (PDF#04-003-4871), while the diffraction peaks at 44.2°, 51.5° and 75.9° are the (111), (200) and (220) crystal planes of elemental cobalt (PDF#04-007-8519), originating from the foamed cobalt substrate; thus, it can be seen that the preparation method is universal.

[0049] FE-SEM and EDS spectra

[0050] The morphology and elemental composition of the Ni-Pt catalyst prepared in Example 1 were characterized using FE-SEM (field emission scanning electron microscopy) and EDS (energy-dispersive X-ray spectroscopy). Figure 2 As shown in the figure, the Ni-Pt catalyst has a nano-flower-like structure, which is uniformly distributed on the 3D nickel foam framework. This structure not only increases the specific surface area and the number of surface active sites of the catalyst, but also facilitates the removal of bubbles and accelerates the exposure of active sites, thereby achieving the purpose of reducing HER overpotential and improving long-term stability. EDS (energy dispersive X-ray spectroscopy) shows that Ni, Pt and O elements are uniformly distributed in the Ni-Pt catalyst, with contents of 74.65, 25.1 and 0.25 wt%, respectively.

[0051] Raman spectral analysis

[0052] Figure 2 The Raman spectrum of the Ni-Pt catalyst prepared in Example 1 is shown, with the peaks located at 552 and 823 cm⁻¹. -1 The two vibrational peaks at that location further confirm the presence of nickel oxide.

[0053] Electrocatalytic performance test

[0054] In a 1M KOH electrolyte, using a graphite rod as the counter electrode, saturated Ag / AgCl as the reference electrode, and the prepared catalyst as the working electrode, the electrochemical performance of the catalysts prepared in Examples 1-16 was tested at a scan rate of 2 mV / s. Figure 4 The electrocatalytic performance of the Ni-Pt, Cu-Pt, Fe-Pt, Zn-Pt, and Co-Pt catalysts prepared in Examples 1 and 2 was evaluated at 10 mA cm⁻¹. -2 At the given current density, the hydrogen evolution overvoltages at each electrode were 8, 89, 66, 31, and 37 mV, respectively. Figure 5 Linear sweep voltammetry (LSV) curves of the Ni-Pt catalyst prepared in Example 1, the pretreated porous nickel foam (NF), and the commercial 20% Pt / C catalyst show that at a current density of 10 mA cm⁻¹... -2 The Ni-Pt catalyst prepared in Example 1 exhibits a very low overpotential, which is far superior to NF and commercial Pt / C (overpotential of 33.2 mV). Figure 6 The graph shows a comparison of the activity of the Ni-Pt catalysts prepared in Example 3 and Example 1. It can be seen that the soaking temperature has a certain influence on the catalytic performance. The Ni-Pt catalyst prepared at room temperature has better performance than those prepared at -5 and 35°C. Figure 7The graph shows a comparison of the activity of the catalysts prepared in Example 4 and Example 1. It can be seen that the catalyst with the best performance is prepared when the amount of chloroplatinic acid (H2PtCl6·6H2O) is 20 mg, that is, the concentration of Pt in the corrosion solution is 1.93 mmol / L. Figure 8 The graph shows a comparison of the activity of the catalysts prepared in Example 5 and Example 1. It can be seen that the catalytic performance first improves and then deteriorates with the increase of soaking time. The catalyst performance is optimal when the soaking time is 4 hours. Figure 9 The graph shows the stability test results of the Ni-Pt catalyst prepared in Example 1. It can be seen that the catalyst exhibits good stability at 10 mA cm⁻¹. -2 The catalyst was continuously tested at a current density for 200 hours. As the test time increased, the voltage hardly decreased, indicating that the catalyst prepared in Example 1 has excellent stability.

[0055] Example 6

[0056] Atomic model:

[0057] Figure 10 The atomic structure model of the Ni-Pt catalyst shows that when Pt is embedded in the Ni lattice, some Ni atoms are replaced by Pt atoms, forming a NiPt alloy layer. Simultaneously, an in-situ NiO layer is formed on its surface through oxidation. Due to the differences in lattice structure and atomic radius between Pt and Ni, where the atomic radius of Pt is [missing information], [missing information]. The atomic radius of Ni is During the Ni-Pt alloying process, atoms rearrange to form a new lattice structure and different interatomic spacings. This process alters the electronic structure of Pt and Ni, helping to reduce the aggregation and precipitation of Pt particles, thus forming a stable Ni-Pt alloy. Furthermore, the NiO nanostructure formed on the NiPt alloy surface effectively protects the NiPt alloy layer, contributing to its stability. In addition, NiO adsorbs on the NiPt alloy surface, forming a NiO / NiPt heterostructure. The electron transfer and interaction between these two structures not only provide a richer array of surface active sites but also effectively regulate the adsorption / desorption balance of reaction intermediates, thereby synergistically improving the electrocatalytic performance of the Ni-Pt catalyst.

[0058] Example 7

[0059] The changes in Pt and Ni content significantly affect the performance of the catalyst; with prolonged soaking time, the Pt content increases ( Figure 8 The performance showed a trend of first increasing and then decreasing, with the optimal performance observed when the soaking time was 4 hours. At this time, the Pt loading in the catalyst was 20.93 μg / cm³ as determined by ICP analysis. 2Based on this result, its mass activity diagram was obtained, which shows that at a voltage of 0.1V, its mass activity is 90.9 times that of commercial 20% Pt / C.

Claims

1. A method for preparing a high-performance nickel-platinum catalytic material, characterized in that, Includes the following steps: Step 1: Pre-treat the nickel foam to remove its surface oxide layer and clean it for later use; Step 2: Dissolve chloroplatinic acid in deionized water and stir to obtain a homogeneous solution with a concentration of 1-2 mmol / L; Step 3: Immerse the nickel foam processed in Step 1 in the solution obtained in Step 2 and react at room temperature for 2 to 6 hours. A NiO / NiPt heterostructure composed of a PtNi alloy layer and NiO nanoparticles on the surface of the alloy layer is formed in situ on the surface of the nickel foam, thus obtaining a high-performance nickel-platinum catalyst material.

2. The preparation method according to claim 1, characterized in that, The pretreatment in step one includes: placing the nickel foam in hydrochloric acid with a concentration of 5-7 mol / L, ultrasonically cleaning for 8-12 minutes, and then rinsing it clean with deionized water.

3. The preparation method according to claim 1, characterized in that, In step two, the pH of the chloroplatinic acid solution is 1 to 3.

4. The preparation method according to claim 1, characterized in that, Includes the following steps: Step 1: Cut 1mm thick nickel foam into 1cm×1cm squares, place them in 6mol / L hydrochloric acid, ultrasonically clean for 10 minutes, and rinse with deionized water 3-5 times for later use. Step 2: Dissolve chloroplatinic acid with a purity of 98% and a platinum content of 38.3% in deionized water and stir to obtain a homogeneous solution with a concentration of 1.5 mmol / L and a pH of 2. Step 3: Immerse the nickel foam processed in Step 1 in the solution obtained in Step 2 at a temperature of 25°C for 4 hours to obtain the final product.

5. The application of the high-performance nickel-platinum catalyst material prepared by the preparation method according to any one of claims 1-4 as a working electrode in the electrolysis of water for hydrogen evolution.

6. The method of using the high-performance nickel-platinum catalyst material prepared by the preparation method according to any one of claims 1-4, characterized in that: A 1 mol / L KOH solution was used as the electrolyte. The prepared high-performance nickel-platinum catalyst was used as the working electrode, saturated Ag / AgCl was used as the reference electrode, and a graphite rod was used as the counter electrode to construct a three-electrode system for testing hydrogen evolution by water electrolysis.

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