Crystalline platinum dioxide catalyst and electrochemical method for its preparation
Patent Information
- Application Number
- CN202510083722.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-20
- Publication Date
- 2026-09-22
- Estimated Expiration
- 2045-01-20
AI Technical Summary
尽管上述制备方法相对成熟，易于控制和规模化生产，但仍存在缺陷：(1)为了确保反应完全进行，传统方法中使用的硝酸钠大大过量，这不仅增加了原料成本，还可能导致资源浪费；(2)传统方法需要在高温下进行长时间的反应或焙烧，这不仅消耗大量能源，还可能增加生产成本，使反应器老化；(3)传统方法通常包括多个步骤，如溶解、沉淀、过滤、干燥等，不仅增加了操作的复杂性，还延长了生产周期
[0019]1、本发明通过精确控制电解质条件和电位参数，能够实现对二氧化铂纳米材料形貌和结构的精细调控，这一方法过程使得催化剂的制备过程更加简单，降低了成本。相比之下，传统方法往往难以实现如此精细的控制，导致催化剂制备过程需要大量的原材料，以及复杂的制备工艺。因此，通过电化学方法制备二氧化铂，能够显著减少反应时间和步骤，大大提高了生产效率。
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Abstract
Description
Technical Field
[0001] This invention relates to a crystalline platinum dioxide catalyst and its electrochemical preparation method, belonging to the field of electrochemical technology. Background Technology
[0002] Platinum dioxide catalyst is a highly active and stable metal oxide catalyst. It has high stability and is reduced by hydrogen to obtain platinum catalyst. It has a large number of active adsorption sites and is widely used in the chemical industry, such as as a hydrogenation catalyst in organic synthesis. It can hydrogenate a variety of groups and requires mild reaction conditions, making it an excellent hydrogen absorption material. Therefore, it has a wide range of application prospects in the field of catalysis. The traditional method for preparing platinum dioxide mainly involves mixing chloroplatinic acid or ammonium chloroplatinate with sodium nitrate and carrying out a eutectic reaction at high temperature. The resulting mixture is then subjected to post-treatment steps such as washing and drying to finally obtain platinum dioxide. Although the above preparation method is relatively mature, easy to control and scale up, it still has some drawbacks: (1) In order to ensure that the reaction is complete, the sodium nitrate used in the traditional method is in large excess, which not only increases the cost of raw materials but may also lead to waste of resources; (2) The traditional method requires a long reaction or calcination at high temperature, which not only consumes a lot of energy but may also increase production costs and cause reactor aging; (3) The traditional method usually includes multiple steps, such as dissolution, precipitation, filtration, and drying, which not only increases the complexity of operation but also prolongs the production cycle.
[0003] Therefore, traditional methods suffer from problems such as high cost, complex and cumbersome processes, and waste of resources. Summary of the Invention
[0004] To address the problems existing in the prior art, this invention provides a crystalline platinum dioxide catalyst and its electrochemical preparation method, which can optimize preparation conditions, simplify the preparation process, and reduce preparation costs.
[0005] To achieve the above objectives, the present invention employs an electrochemical preparation method for a crystalline platinum dioxide catalyst, comprising the following steps:
[0006] S1. Prepare Pt(100) nanoparticles and load them directly onto a glassy carbon electrode using an aqueous solution as the working electrode.
[0007] S2. Place the working electrode from step S1 in an electrolyte solution, which includes 0.1-1.0M perchloric acid and 1.0-3.0M sodium perchlorate solution. Adjust the concentration of perchlorate ions to increase the amount of non-specifically adsorbed perchlorate ions on the surface of Pt(100) nanoparticles. It should be noted that non-specific adsorption refers to the adsorption of substances on a surface that does not depend on specific intermolecular interactions or coordination bonds. This adsorption occurs when a substance comes into contact with a solid surface in a solution. Due to non-covalent forces, such as van der Waals forces, electrostatic forces, and hydrophobic interactions, the compound is adsorbed onto the solid surface.
[0008] S3. Adjust the potential and duration of the constant potential step process, including: increasing the constant potential step process from 0.15V to 1.4V, with each potential step lasting 380s, maintaining a constant potential of 1.4V for >1h, and determining the crystalline state of platinum dioxide by Raman spectroscopy.
[0009] S4. Adjust the pH of the electrolyte solution and the concentration of perchlorate ions to obtain the desired crystalline platinum dioxide catalyst.
[0010] As an improvement, in step S1, a colloidal method is used to prepare Pt(100) nanoparticles with clean surfaces, controllable shapes, and easy availability.
[0011] As an improvement, the colloidal method includes the following steps: adding sodium hydroxide to a potassium chloroplatinate and sodium polyacrylate solution with a pH of 6-8 to induce precipitation, washing the precipitate, and obtaining Pt(100) nanoparticles.
[0012] As an improvement, the molar concentration ratio of potassium chloroplatinate to sodium polyacrylate is 1:(4-6).
[0013] As an improvement, in step S1, the Pt(100) nanoparticles are ultrasonically dispersed evenly, and 8 μL is taken each time and dropped onto the glassy carbon electrode in two separate drops. The loading is completed after the nanoparticles have dried.
[0014] As an improvement, in step S2, the concentration of perchlorate ions is adjusted to 1.0-3.0 M.
[0015] In a second aspect, the present invention also provides a crystalline platinum dioxide catalyst, which is prepared by the electrochemical preparation method described above.
[0016] Mechanism of the invention:
[0017] Perchlorate ions aggregated on the Pt(100) surface and hydrated hydrogen ions in the solution affect the adsorption of water on the Pt(100) surface. Perchlorate ions exert a pulling force on water outward from the interface, while hydrated hydrogen ions push adsorbed water outward. Neither of these factors is conducive to the surface adsorption of water. The oxygen in platinum dioxide comes from surface adsorbed water. Therefore, when surface adsorption of adsorbed water is inhibited, it will affect the diffusion of oxygen into the interior of the platinum lattice, thereby affecting the type of platinum dioxide formed. If oxygen diffuses quickly, amorphous platinum dioxide will be formed, while if it diffuses slowly, crystalline platinum dioxide will be formed.
[0018] Compared with the prior art, the beneficial effects of the present invention are:
[0019] 1. This invention enables precise control of the morphology and structure of platinum dioxide nanomaterials by controlling electrolyte conditions and potential parameters. This method simplifies the catalyst preparation process and reduces costs. In contrast, traditional methods often struggle to achieve such precise control, resulting in catalyst preparation requiring large quantities of raw materials and complex processes. Therefore, preparing platinum dioxide via electrochemical methods significantly reduces reaction time and steps, greatly improving production efficiency.
[0020] 2. This invention combines in-situ characterization techniques to monitor changes on the electrode surface in real time during the reaction process and to gain a deeper understanding of the electrochemical process of platinum dioxide preparation under different electrolyte conditions. The application of this technique makes the preparation process more controllable and simpler, helping to improve the production efficiency of platinum dioxide; traditional methods lack this real-time monitoring capability.
[0021] 3. The preparation method of this invention is efficient and precise, avoiding unnecessary waste and repetitive labor. It does not require a large amount of raw materials, and the reaction can be carried out at room temperature, which helps to reduce production costs and promotes green and low-carbon production. In contrast, traditional methods require more raw materials and energy input, involve continuous high-temperature reactions, and have more complex post-processing steps, resulting in higher production costs.
[0022] 4. The raw materials for this invention include potassium chloroplatinate, perchloric acid, etc., which are readily available on the market and relatively stable in price. The equipment required for this invention is already available as a mature product on the market. The process flow of this invention is relatively simple, easy to master and operate, and therefore has broad prospects for industrialization and can be mass-produced.
[0023] 5. Electrochemical preparation of platinum dioxide can improve its electrochemical efficiency, reduce production costs, and decrease energy consumption by optimizing electrode materials, electrolyte pH and potential parameters, and selecting appropriate electrolyte types and concentrations. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 TEM characterization of the morphology of Pt(100) nanoparticles synthesized in Example 1 of this invention. Figure 1 ;
[0026] Figure 2 TEM characterization of the morphology of Pt(100) nanoparticles synthesized in Example 1 of this invention. Figure 2 ;
[0027] Figure 3 In Example 2 of this invention, the working electrode was placed in 0.1M perchloric acid, and 0M and 3.0M sodium perchlorate were added. Raman spectroscopy was performed on the surface of Pt(100) nanoparticles during the constant potential step process.
[0028] Figure 4 In Example 3 of this invention, the working electrode was placed under different pH conditions, and the ion concentrations of 0-0.1M perchloric acid and 0-3.0M perchlorate were adjusted to perform Raman spectroscopy characterization of the surface of Pt(100) nanoparticles during the constant potential step process.
[0029] Figure 5 In Example 4 of this invention, the working electrode was placed in a solution of 0.1 M perchloric acid and 3.0 M perchlorate ions at pH 1, and Raman spectra were recorded at different termination potentials.
[0030] Figure 6 This is a comparison of the Raman spectra of platinum dioxide from Example 5 of the present invention and commercial platinum dioxide. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.
[0032] Example 1
[0033] A method for preparing Pt(100) nanoparticles includes the following steps:
[0034] (1) The prepared 0.10mM K2PtCl4 (potassium chloroplatinate) solution was subjected to dark aging treatment at 25℃ for 24h. Then, 0.8mL of 0.10M sodium polyacrylate solution (molecular weight about 2100g / mol) was added to the aged K2PtCl4 solution to ensure that the molar ratio of K2PtCl4 to sodium polyacrylate was maintained at 1:5. Then, the pH value of the solution was adjusted to 7.5 using an appropriate amount of HCl.
[0035] (2) The prepared reaction solution was deoxygenated with argon for 20 minutes, and then hydrogen was introduced for reduction reaction for 8.0 minutes. The reaction container was sealed and left overnight to obtain a light golden solution.
[0036] (3) Add two NaOH pellets to the liquid after the reaction is complete. After precipitation, centrifuge at 10,000 rpm and rinse with ultrapure water multiple times (repeated 3 to 4 times) to completely remove sodium polyacrylate from the surface of the nanoparticles to obtain Pt(100) nanoparticles. Store the Pt(100) nanoparticles in 1.5 mL of ultrapure water.
[0037] Characterization of Pt(100) nanoparticles: The morphology of the Pt(100) nanoparticles synthesized in Example 1 was characterized by electron microscopy (TEM). Figures 1-2 As shown in the TEM image, the Pt(100) nanoparticles are clearly cubic in shape and well dispersed, with clear outlines and corners.
[0038] Example 2
[0039] The Pt(100) nanoparticles prepared in Example 1 were ultrasonically dispersed evenly. 8 μL was taken each time and dropped onto the glassy carbon electrode in two separate drops. After the nanoparticles dried, the working electrode was obtained.
[0040] The working electrode was placed in an electrolyte solution (including 0.1 M perchloric acid and 0 M sodium perchlorate solution), and the constant potential was increased from 0.15 V to 1.4 V, with each potential step lasting 380 s.
[0041] As the concentration of perchlorate ions in the electrolyte solution was gradually increased (from 0 M to 3.0 M), the Raman spectrum at the electrode surface increased from 590 cm⁻¹. -1 The single Raman spectral peak transforms to 510 cm⁻¹ -1 and 550cm -1 The double Raman spectral peaks indicate the presence of crystalline platinum dioxide; 935 cm⁻¹ -1 The Raman spectral peaks are the Raman shifts of the Cl-O bond vibrations of the perchlorate ion.
[0042] like Figure 3 As shown, the Raman spectrum of a 0.1M perchloric acid solution without the addition of sodium perchlorate solution shows a value of 590 cm⁻¹. -1 A single peak was observed; when 3.0 M sodium perchlorate solution was added to a 0.1 M perchloric acid solution, the Raman spectrum showed a peak at 515 cm⁻¹. -1 and 561cm -1 Twin peaks.
[0043] Example 3
[0044] Prepare a working electrode loaded with Pt(100) nanoparticles;
[0045] The non-specific adsorption of the anion ClO4 - With the concentration constant, change H + Concentration is used to adjust the pH of the electrolyte solution;
[0046] In electrolytes with pH values of 5.0, 3.0, 1.0, 0.5, 0.3, and 0.1, a constant potential step was applied to the working electrode loaded with Pt(100) nanoparticles, increasing the potential from 0.15 V to 1.4 V with a step potential difference of 0.05 V. Each potential step lasted for 380 s, and the constant potential at 1.4 V was maintained for more than 1 h. The change in the intensity of the platinum-oxygen vibration peak signal in platinum dioxide was monitored by Raman spectroscopy at each potential.
[0047] like Figure 4 As shown, the crystallinity of the prepared platinum oxide increases with decreasing pH, reaching 510 cm⁻¹. -1 and 550cm -1 The intensity of the wavenumber band signal increases with decreasing pH, and the difference in intensity between the two bands decreases with decreasing pH. This indicates that decreasing pH is beneficial for the preparation of α-PtO2 crystals.
[0048] Example 4
[0049] Prepare a working electrode loaded with Pt(100) nanoparticles;
[0050] The working electrode was placed in an electrolyte solution of 0.1 M perchloric acid and 3.0 M sodium perchlorate, pH=1. The starting potential of the constant potential step method was set to 0.15 V, and the ending potentials were set to 1.1 V, 1.2 V, 1.3 V and 1.4 V, respectively. The step potential difference was 0.05 V. Each step potential was held for 380 s, and the vibration peak of the platinum-oxygen bond of platinum dioxide was monitored by Raman spectroscopy.
[0051] like Figure 5 As shown, when the termination potential exceeds 1.2V, platinum-oxygen species have been generated on the electrode surface. A distinct Raman band appears when the potential is increased to 1.3V, and the band becomes even more pronounced as the potential continues to rise to 1.4V, clearly showing a 510cm band.-1 and 550cm -1 The double Raman spectral peaks are observed at a relatively small potential range. At higher potentials, the changes in the Raman bands with increasing potential cannot be clearly determined.
[0052] Example 5
[0053] Prepare a working electrode loaded with Pt(100) nanoparticles;
[0054] The working electrode was placed in an electrolyte solution of 0.1 M perchloric acid and 3.0 M sodium perchlorate at pH 1. The constant potential was increased from 0.15 V to 1.4 V with a step potential difference of 0.05 V. The duration of each potential was 380 s. Raman spectroscopy was performed after the constant potential at 1.4 V was maintained for more than 1 h.
[0055] like Figure 6 As shown, at 511cm -1 and 556cm -1 A signal peak appeared in the Raman spectrum at the specified wavenumber, consistent with the Raman shift of commercial platinum dioxide. This indicates that the crystalline platinum dioxide prepared by this method meets the relevant requirements.
[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. An electrochemical preparation method for a crystalline platinum dioxide catalyst, characterized in that, Includes the following steps: S1. Prepare Pt(100) nanoparticles, wherein the Pt(100) nanoparticles are cubic in shape; after the Pt(100) nanoparticles are ultrasonically dispersed evenly, they are drop-coated onto a glassy carbon electrode in two batches and used as working electrodes after drying. S2. Place the working electrode from step S1 in an electrolyte solution, which includes 0.1-1.0 M perchloric acid and 1.0-3.0 M sodium perchlorate solution. Adjust the concentration of perchlorate ions to increase the amount of non-specifically adsorbed perchlorate ions adsorbed on the surface of Pt(100) nanoparticles. S3. A constant potential step is performed from 0.15 V to 1.4 V, with a step potential difference of 0.05 V. Each potential step lasts for 380 s, and the constant potential at 1.4 V is maintained for >1 h. During each potential step, the platinum-oxygen vibration peak is monitored in real time by in-situ electrochemical Raman spectroscopy. When the double characteristic Raman peaks of 510 cm⁻¹ and 550 cm⁻¹ appear, it is determined that crystalline platinum dioxide has been generated. S4. Adjust the pH of the electrolyte solution and the concentration of perchlorate ions to obtain the desired crystalline platinum dioxide catalyst.
2. The electrochemical preparation method of a crystalline platinum dioxide catalyst according to claim 1, characterized in that, In step S1, Pt(100) nanoparticles with clean surfaces, controllable shapes, and easy availability are prepared using a colloidal method.
3. The electrochemical preparation method of a crystalline platinum dioxide catalyst according to claim 2, characterized in that, The colloidal method includes the following steps: adding sodium hydroxide to a mixed solution of potassium chloroplatinate and sodium polyacrylate at pH 6-8 to induce precipitation, washing the precipitate, and obtaining Pt(100) nanoparticles.
4. The electrochemical preparation method of a crystalline platinum dioxide catalyst according to claim 3, characterized in that, The molar ratio of potassium chloroplatinate to sodium polyacrylate is 1:(4-6).
5. The electrochemical preparation method of a crystalline platinum dioxide catalyst according to claim 1, characterized in that, In step S1, Pt(100) nanoparticles are ultrasonically dispersed evenly. 8 μL is taken each time and dropped onto the glassy carbon electrode in two separate drops. The loading is completed after the nanoparticles have dried.
6. The electrochemical preparation method of a crystalline platinum dioxide catalyst according to claim 1, characterized in that, In step S2, the concentration of perchlorate ions is adjusted to 1.0-3.0 M.