Preparation and application of a three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam

Abstract

The present invention designs and prepares a three-dimensional self-supporting catalyst material, Pt / Ni Foam. By rationally controlling the structure modifier sodium iodide and the surfactant PVP added during the reaction process, the highly active precious metal material Pt can be uniformly and highly dispersedly grown on the self-supporting conductive substrate material nickel foam through a convenient one-step method, forming a multifunctional, structurally stable electrocatalytic active material. The Pt content of the obtained sample material is only 0.1%-1%. This material can be conveniently applied to electrochemical catalytic water decomposition and recyclable zinc-air batteries, and has broad application prospects in future energy conversion devices.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical catalytic energy conversion. Specifically, the present invention relates to the preparation and application of a three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam, and this application focuses on the field of energy conversion. Background Art

[0002] With fossil energy consumption increasing, finding alternatives to meet today's massive energy needs has become a major global concern. While renewable energy is infinite compared to fossil fuels, the current efficiency of converting, storing, and transporting these unstable renewable energy sources is low, limiting the economic viability of the renewable energy industry. Therefore, developing simpler and more efficient methods for energy conversion and storage is a key research direction in addressing this energy challenge.

[0003] Hydrogen energy has a large energy reserve, is lightweight, and is easy to transport, making it an excellent energy carrier. Currently, the main way to convert energy into hydrogen is through the electrolysis of water to produce hydrogen. However, the process of electrolysis of water to produce hydrogen requires overcoming the energy barriers of the HER and OER processes, which consumes a lot of energy. Therefore, designing and preparing usable HER and OER electrochemical catalysts can solve this problem to a large extent. The precious metal Pt is one of the best known HER electrocatalytic materials. It has a lower hydrogen evolution potential and a H2O that is closer to zero. * Adsorption-desorption energy (ΔG H* However, for precious metals, balancing cost and efficiency is an urgent issue that needs to be addressed. Therefore, there is a pressing need to develop and design catalytic materials that can fully utilize the catalytic activity of Pt and have a stable support. Summary of the Invention

[0004] The purpose of this invention is to design and prepare a three-dimensional, self-supporting electrochemical catalyst material, Pt / Ni Foam, and explore its practical application in the field of energy conversion. The advantage of this catalyst lies in the ability to evenly disperse precious metal Pt nanoparticles on a three-dimensional, self-supporting nickel foam substrate. This allows for a high specific surface area and stable chemical structure of platinum while maintaining a low platinum loading, thereby providing excellent catalytic effects in both HER, OER, and zinc-air batteries. Furthermore, in this catalyst material, the electronic structures of Pt and Ni are similar, forming a very stable heterostructure, further improving its stability and electron transfer efficiency.

[0005] The technical solutions of the present invention are as follows:

[0006] The present invention provides a three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam. This material uses commercial nickel foam as a substrate. After treatment, a uniform layer of Pt nanoparticles is grown on its surface through a simple oil bath heating reaction, forming a catalyst with a heterogeneous structure. The uniform loading of Pt nanoparticles is achieved through the directional adsorption and guidance of structure-modifying agent ions, specifically: Cl - , I - or Br - Ions can be selectively adsorbed on the surface of nickel foam, and at the same time, the precious metal ions in the solution are adsorbed on the surface of nickel foam through coordination force and electrostatic force, making the deposition and adsorption of Pt more uniform, and through the bridging effect of halogen ions, there is a stronger binding force and interaction with Ni, resulting in better electrochemical potential.

[0007] In some examples, the measured Pt loading amount is 0.1-1%, meeting the requirement of low Pt loading amount.

[0008] In an embodiment of the present invention, the advantages of the three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam are: in addition to having a stable three-dimensional network structure of the nickel foam base at the micron level, it provides a stable current transmission channel, which makes it possible to quickly transport in the electrolyte solution in the energy conversion example; and in this process, the addition of structure regulators and surfactants provides reaction active sites for the uniform growth of Pt, so that Pt can grow uniformly and stably on the surface of the nickel foam, forming a stable heterogeneous structure, further weakening the electron transport barrier, and reducing the energy loss in the energy conversion process; the uniform dispersion distribution of Pt also improves the overall utilization rate of Pt, reduces the cost of preparing and synthesizing this catalyst material, and improves the economic efficiency of this invention.

[0009] An embodiment of the present invention further provides a method for preparing a three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam, which specifically comprises the following steps:

[0010] (1) The cut nickel foam is pretreated by ultrasonic immersion; that is, the cut nickel foam of 1×3 cm is firstly treated by 0.5-2M hydrochloric acid solution and acetone. 2 The nickel foam is pretreated by ultrasonic immersion, and the ultrasonic treatment is carried out for 10 to 30 minutes respectively, in order to remove the surface oxide layer and some hydrophobic oil impurities that may be formed during the synthesis, transportation and storage process. After washing, it is washed with deionized water for 1 to 3 times and dried in vacuum to obtain dry pretreated nickel foam.

[0011] (2) preparing a reaction solution A; the components of the reaction solution A are: adding an appropriate amount of halogen salt and a surfactant to deionized water, and stirring until the solution turns into a uniform, transparent light yellow color;

[0012] (3) The nickel foam was dried under vacuum at low temperature and then added to the reaction solution A, and then an aqueous solution of chloroplatinic acid was added dropwise under uniform stirring to form a uniform dark red solution;

[0013] (4) The reaction vessel is placed in a stirring and heating oil bath, stirred and heated at a constant temperature, and then cooled naturally. The obtained nickel foam is cleaned and dried to obtain the three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam material as described above.

[0014] In the preparation method of the three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam in some embodiments, the halogen salt in the prepared solution is NaI with a mass concentration of 5 to 15 g / L; the surfactant used is PVP (K30) with a PVP concentration of 10 to 50 g / L, and the preferred ratio is 3:8.

[0015] In the preparation method of the catalyst material Pt / Ni Foam in some embodiments, the concentration of the added chloroplatinic acid aqueous solution is 0.5-3 M, and the amount thereof added is 0.5-5 mL.

[0016] In some embodiments of the method for preparing the catalyst material Pt / Ni Foam, it is characterized in that the oil bath heating temperature is 60-100° C., and the reaction time is 0.5-4 h; the optimal conditions are 80° C. and the reaction time is 1 h.

[0017] In some embodiments, the control agent used is NaI, the mass concentration is 6g / L, the concentration of the added chloroplatinic acid is 1M, the amount is 1mL, the reaction temperature is 80°C, the reaction time is 0.5h, and the percentage of Pt obtained is 0.12%.

[0018] In some embodiments, the control agent used is NaBr, the mass concentration is 8g / L, the concentration of the added chloroplatinic acid is 2M, the amount is 2mL, the reaction temperature is 80°C, the reaction time is 4h, and the percentage of Pt obtained is 0.47%.

[0019] In some embodiments, the control agent used is KCl, the mass concentration is 10g / L, the concentration of the added chloroplatinic acid is 1M, the amount is 5mL, the reaction temperature is 100℃, the reaction time is 1h, and the percentage of Pt obtained is 0.54%.

[0020] The present invention also proposes a specific method for the catalyst material Pt / Ni Foam obtained in the embodiment that can be applied to electrocatalytic water decomposition. The steps for the HER half reaction are as follows: using the Pt / Ni Foam catalyst material as a working electrode, a platinum sheet or a platinum wire as a counter electrode, a saturated calomel electrode or a mercury oxide electrode as a reference electrode, and a 1M KOH solution or a 0.5M H2SO4 solution as an electrolyte, and connecting according to a three-electrode system to obtain the LSV curve of voltage and current; and for the OER half reaction, using the Pt / Ni Foam catalyst material as a working electrode, a platinum sheet or a platinum wire as a counter electrode, a mercury oxide electrode as a reference electrode, and a 1M KOH solution as an electrolyte, and connecting according to a three-electrode system to obtain the LSV curve of voltage and current.

[0021] The present invention also directly applies the catalyst material Pt / Ni Foam obtained in the embodiment to electrocatalytic water decomposition. The specific steps are: the Pt / Ni Foam catalyst material is simultaneously used as two working electrodes, and after connecting them into a two-electrode system, a voltage within a certain range is applied, water is decomposed at the cathode to generate hydrogen, and water is decomposed at the anode to generate oxygen, and the LSV curve of water decomposition is obtained.

[0022] The present invention also assembles the catalyst material Pt / Ni Foam obtained in the example into button primary and secondary zinc-air batteries. The specific steps are: assembling an air collector layer, a working electrode formed by directly cutting the catalyst material Pt / Ni Foam, a diaphragm containing an electrolyte, and a zinc source into the button battery using a packaging machine. It is characterized in that the button battery shell used is a 17-hole CR2025, the air collector layer is a carbon cloth material loaded with activated carbon, the working electrode is a Pt / Ni Foam catalyst material cut into a diameter of 19mm, the electrolyte in the primary battery is a 6M KOH solution, and in the secondary battery it is 6M KOH + 0.2M ZnAc2, and the zinc source is zinc flakes or zinc powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The synthesis flow chart of the catalyst material Pt / Ni Foam in the present invention

[0024] Figure 2 Characterization diagram of the catalyst material of the present invention under a low-magnification scanning electron microscope

[0025] Figure 3 Characterization diagram of the catalyst material of the present invention under a high-magnification scanning electron microscope

[0026] Figure 4 The linear voltammetric curve of HER for electrocatalytic water splitting using the catalyst material Pt / Ni Foam in the present invention is shown in Figure 2.

[0027] Figure 5 The linear voltammetric curve of the OER of the catalyst material Pt / Ni Foam used for electrocatalytic water decomposition in the present invention is

[0028] Figure 6 The linear voltammetric curve of the catalyst material Pt / Ni Foam used for electrocatalytic water splitting in the present invention is

[0029] Figure 7 The discharge polarization curve of the catalyst material Pt / Ni Foam used in the button primary zinc-air battery of the present invention is

[0030] Figure 8 The charge and discharge polarization curve of the catalyst material Pt / Ni Foam used in the button secondary zinc-air battery of the present invention is

[0031] Figure 9 The preparation and application flow chart of the present invention

[0032] Figure 1 The synthesis steps of the catalyst material Pt / Ni Foam are described in the paper. Pt is grown onto the / Ni Foam in a system containing PVP and NaI using a low-temperature oil bath. Figure 2 and Figure 3 It is a scanning electron microscope characterization image at different magnifications; Figure 4 and Figure 5 The performance test diagrams of the catalyst material Pt / Ni Foam electrocatalytic water splitting HER and OER were characterized respectively, and it has relatively low overpotential under different solution conditions; Figure 6 The voltammogram curves of water electrolysis with direct current applied to the positive and negative electrodes of the catalyst material Pt / Ni Foam are shown. Compared with the blank Ni Foam, the decomposition potential of water has dropped significantly. Figure 7 and Figure 8 The polarization curves of the catalyst material Pt / Ni Foam used as an electrode material in button primary or secondary batteries show that the discharge curve has a higher discharge voltage at a higher current density, and the charge-discharge curve has a smaller polarization voltage difference. Figure 9 This is the preparation and application flow chart of the patent of this invention. Specific implementation methods

[0033] The specific implementation method of the catalyst material obtained by the present invention is: first pre-treat the cut nickel foam, that is, first use 0.5-2M hydrochloric acid solution and acetone to treat the cut 1×3cm 2The nickel foam is pretreated by ultrasonic immersion for 10 to 30 minutes respectively, in order to remove the surface oxide layer and some hydrophobic oil impurities that may be formed during the synthesis, transportation and storage process. After washing, it is rinsed with deionized water for 1 to 3 times and dried in a vacuum oven at 40°C for one hour to obtain a dry pretreated nickel foam.

[0034] Then, reaction solution A was prepared; the components of reaction solution A were added to deionized water with appropriate amounts of NaI and PVP, and stirred until a uniform, transparent light yellow color was obtained; then, the nickel foam was vacuum-dried at low temperature and added to reaction solution A, and an aqueous solution of chloroplatinic acid was added dropwise under uniform stirring, ultimately forming a uniform dark red solution.

[0035] Subsequently, a reaction vessel, such as a 40 mL glass bottle, is placed in a heated stirring and heating oil bath. After constant temperature stirring and heating at a preset temperature of 60-100° C. for 1 hour, the reactor is taken out and allowed to cool naturally. After cooling, the obtained nickel foam is taken out and washed with deionized water and anhydrous ethanol in turn. After drying, the Pt / Ni Foam catalyst material as described above is obtained.

[0036] The obtained catalyst material Pt / Ni Foam is then directly clamped as a working electrode on the working electrode clamp in the three-electrode system, placed in 0.5M H2SO4 or 1MKOH electrolyte, and the set test program is run to obtain the HER and OER linear voltammetric curves of the material obtained in the present invention under acidic and alkaline conditions.

[0037] The resulting Pt / Ni Foam catalyst material is then cut into 19mm diameter discs. The positive electrode housing, air current collector, working electrode, electrolyte separator, zinc electrode, and negative electrode housing are assembled into coin cells using a packaging machine in the correct order. After the coin cells rest for several hours, they are connected to a Blue Electric test system for testing. By running the pre-set primary or secondary zinc-air battery test program, the primary or secondary polarization curves for the zinc-air battery obtained are obtained.

Claims

1. A three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam, characterized in that: The composite catalyst material uses nickel foam as a substrate and is evenly loaded with Pt nanoparticles through a one-step oil bath heating process. The resulting material can be used in various electrocatalytic and energy conversion scenarios. The mass fraction of Pt on the nickel foam substrate accounts for only 0.1-0.5% of the entire catalyst material. The preparation method of the three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam includes the following steps: (1) performing ultrasonic immersion pretreatment on the cut nickel foam; (2) preparing a reaction solution A by adding an appropriate amount of a structure regulating agent, one of NaI, NaBr, and KCl, and a surfactant to deionized water and stirring until homogeneous and transparent; (3) drying the nickel foam at low temperature in a vacuum oven and adding it to the reaction solution A, followed by dropwise addition of an aqueous solution of chloroplatinic acid under uniform stirring to form a uniform solution; (4) The reaction vessel is placed in a stirring and heating oil bath, stirred and heated at a constant temperature, and then cooled naturally. The obtained nickel foam is washed and dried to obtain a Pt / Ni Foam catalyst material.

2. The three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam according to claim 1, characterized in that: The required pretreatment steps are:

1. Cut the 1×3 cm 2 The nickel foam is pretreated by ultrasonic immersion, and the ultrasonic time is 10 to 30 minutes.

3. The three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam according to claim 1, characterized in that: The concentration of the structure regulator used in the reaction system is 0.05-0.2M.

4. The three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam according to claim 1, characterized in that: The surfactant used is one of the non-ionic surfactants PVPK30 and PVPK100; and the mass concentration of the structure regulator used in the reaction system is 20-50 mg / mL.

5. The three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam according to claim 1, characterized in that: The concentration of the aqueous chloroplatinic acid solution added dropwise is 0.5 to 3 M, and the amount added dropwise is 0.5 to 5 mL.

6. The use of a three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam according to claim 1, characterized in that: Used in electrochemical catalysis or assembly of zinc-air batteries.

7. The use of a three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam according to claim 6, characterized in that: The construction of a simple electrocatalytic water splitting device includes the following steps: through a three-electrode system, Pt / Ni Foam catalyst material is used as the working electrode, platinum wire or platinum sheet electrode is used as the counter electrode, saturated calomel electrode or mercury oxide electrode is used as the reference electrode, and 0.5M H2SO4 solution, 1M PBS solution or 1M KOH solution is used as the electrolyte solution.

8. The use of a three-dimensional self-supporting electrochemical catalyst material Pt / Ni Foam according to claim 6, characterized in that: The assembly of button primary and secondary zinc-air batteries includes the following steps: encapsulating zinc powder or zinc sheet, electrolyte diaphragm, Pt / Ni Foam catalyst material as working electrode and air collecting layer in a button electrode with holes in the positive electrode. The button battery electrode shell is CR2032, the electrolyte is 6M KOH or a mixed solution of 6M KOH and 0.2M ZnAc2, and the air collecting layer used is carbon paper with activated carbon material coated on the surface.

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