Fuel cell cathode compact platinum monatomic layer catalyst and preparation and application thereof

Abstract

The invention discloses a fuel cell cathode compact platinum monatomic layer catalyst and preparation and application thereof, and belongs to the technical field of fuel cell catalysts. Aiming at the problem that the dosage of noble metal platinum in an electrode is reduced on the premise of ensuring the activity in commercial application of a current fuel cell, the preparation method of the fuel cell cathode compact platinum monatomic layer catalyst comprises the following steps: mixing potassium chloroplatinite and sulfuric acid to obtain a chloroplatinic acid solution; mixing copper and carbon to obtain a copper-carbon mixture; and uniformly mixing the copper-carbon mixture with a chloroplatinic acid solution, stirring while heating, and carrying out Pt monatomic layer replacement to obtain the platinum monatomic layer catalyst. The method has the advantages of environmental friendliness, convenience, rapidness, simple reaction conditions, easiness in operation and the like. The constructed platinum monatomic layer catalyst based on the nano-copper-carbon composite material can be applied to fuel cells and other cells and electrochemical reactors.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cell catalysts, and in particular relates to a dense platinum monoatomic layer catalyst for a fuel cell cathode and a preparation and application thereof. Background Art

[0002] A fuel cell is a device that converts the chemical energy of a fuel directly and efficiently into electrical energy. It is also called an electrochemical generator. It is the fourth power generation technology after hydropower, thermal power generation, and atomic power generation. Among them, proton exchange membrane fuel cells have attracted widespread attention due to their low operating temperature, fast startup, high specific power, simple structure, easy operation, and environmental friendliness. The electrode is the core component of the fuel cell and is the place where the electrochemical reaction occurs. In order to realize the commercial application of fuel cells, one of the problems that urgently needs to be solved is to reduce the amount of precious metal platinum in the electrode while ensuring activity, thereby reducing costs. Summary of the invention

[0003] In view of the problem of reducing the amount of precious metal platinum in the electrode while ensuring the activity in the current commercial application of fuel cells, the present invention provides a dense platinum monoatomic layer catalyst for the cathode of a fuel cell and its preparation and application.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing a dense platinum monoatomic layer catalyst for a fuel cell cathode comprises the following steps: Step 1, mixing potassium chloroplatinite (K2PtCl4) and sulfuric acid (H2SO4) to obtain a chloroplatinic acid solution; Step 2, mixing copper and carbon to obtain a copper-carbon mixture; Step 3, the copper-carbon mixture is uniformly mixed with the chloroplatinic acid solution, and stirred while heating to perform a single atomic layer replacement of Pt to obtain a platinum single atomic layer catalyst.

[0005] Furthermore, in step 1, the dosage ratio of potassium chloroplatinite (K2PtCl4) to sulfuric acid (H2SO4) is 1:10.

[0006] Furthermore, the ratio of copper to carbon in step 2 is 1:9 to 8:2. Further, the ratio of the copper-carbon mixture to the chloroplatinic acid solution is 1:10 to 10:1. Furthermore, the heating and stirring in step 3 specifically includes: the heating temperature is 30° C. to 60° C., the stirring speed is 300 rpm to 500 rpm, or the ultrasonic time is greater than 3 h.

[0007] A dense platinum monoatomic layer catalyst for a fuel cell cathode.

[0008] Furthermore, platinum in the catalyst is loaded on the copper surface to form lattice stripes.

[0009] The invention discloses an application of a dense platinum monoatomic layer catalyst for a fuel cell cathode in a membrane electrode system.

[0010] Furthermore, the catalyst suspension is transferred to the electrode surface by using a hanging drop method; or the catalyst suspension is evenly sprayed onto the surface of the ion exchange membrane or the gas diffusion layer.

[0011] The principle is: copper and carbon are directly mixed with chloroplatinic acid solution, and the different metal activity orders of Cu and Pt are used. After the replacement reaction, copper replaces platinum from its precursor, thereby obtaining a single atomic layer of platinum on the surface of copper, and at the same time realizing the loading of metal catalyst on carbon material. The process reacts quickly, the reaction conditions are simple, the time is short, and it can be completed in one step.

[0012] Compared with the prior art, the present invention has the following advantages: The method of the present invention has the advantages of being environmentally friendly, convenient and fast, having simple reaction conditions, and being easy to operate. The constructed platinum monoatomic layer catalyst based on nano copper-carbon composite material can be applied to fuel cells and other batteries and electrochemical reactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a transmission electron microscope photograph of the surface morphology of the copper-carbon nanocomposite material coated with a platinum layer.

[0014] Figure 2 It is the interplanar spacing of the copper-carbon nanocomposite material coated with a platinum layer.

[0015] Figure 3 This is the XRD pattern of the copper-carbon nanocomposite material coated with a platinum layer.

[0016] Figure 4 This is the XPS spectrum of the copper-carbon nanocomposite material coated with a platinum layer.

[0017] Figure 5 It is the CV polarization curve of the Pt single atomic layer catalyst prepared by the method of the present invention.

[0018] Figure 6 It is the ORR polarization curve of the Pt single atomic layer catalyst prepared by the method of the present invention.

[0019] Figure 7 It is a hydrogen-space polarization curve of a Pt single atomic layer catalyst prepared by the method of the present invention under 100% humidity. DETAILED DESCRIPTION

[0020] In order to gain a deeper understanding of the present invention, we will provide a comprehensive and detailed description of the present invention. However, the present invention has multiple implementations and is not limited to the specific examples listed herein. The presentation of these examples is intended to deepen the comprehensive understanding of the disclosure of the present invention.

[0021] Example 1

[0022] Step 1, take 272 μL of concentrated H2SO4 (98%) and 207.5 mg of K2PtCl4 and dissolve them in 100 mL of deionized water to synthesize a chloroplatinic acid mixed solution.

[0023] Step 2: weigh 60 mg of copper nanoparticles and 40 mg of carbon black and put them into a beaker to obtain a copper-carbon mixture.

[0024] Step 3, dissolve 100 mg of the copper-carbon mixture in 100 mL of a chloroplatinic acid mixed solution, heat and stir (50°C, 300 rpm) for 3 hours, then wash it repeatedly with deionized water three times, vacuum dry the washed catalyst suspension at 60°C for 6 hours, and collect the Pt single atomic layer catalyst.

[0025] Step 4: Drop or spray the Pt single atomic layer catalyst prepared in step 3 on the glassy carbon electrode and the surface of Nafion211 membrane. Take 2 mg of Pt single atomic layer catalyst, 0.7 mL of IPA, 0.7 mL of DI H2O, and 11.2 µL of NafionD521, mix them evenly and ultrasonicate to make ink. Take 20 µL of ink and evenly drop it on the surface of glass carbon (GC) electrode for rotating disk test; take 34.6 mg Pt catalyst, 1.43 mL nPA, 2.67 mL DI H2O, and 81.5 µL NafionD2020, mix them evenly and ultrasonically to make ink, which is sprayed on one side of Nafion 211 membrane as cathode; take 9.3 mg TKK (50%), 1.08 mLnPA, 2.02 mL DI H2O, and 21.9 µL Nafion D2020, mix them evenly and ultrasonically to make ink, which is sprayed on the other side of Nafion 211 membrane as anode.

[0026] Microstructure morphology characterization and spectral information of the platinum monoatomic layer catalyst prepared by the method of the present invention.

[0027] TEM images of the copper-carbon nanocomposite supported platinum monoatomic layer catalyst prepared by the method of the present invention are shown in FIG. Figure 1 ,from Figure 1 It can be clearly observed that the metal nanoparticles are uniformly loaded on the carbon support.

[0028] Figure 2Lattice fringes can be observed with a width of 0.23 nm, which is the Pt (111) crystal plane, proving that Pt is well loaded on the surface of nanocopper.

[0029] XRD and XPS of copper-carbon nanocomposite supported platinum monoatomic layer catalyst Figure 3 and Figure 4 , the characteristic peak of Pt can be clearly seen from the figure, proving the successful reduction and deposition of platinum.

[0030] The Pt single atomic layer catalytic electrode prepared by the method of the present invention is characterized by cyclic voltammetry (CV) and oxygen reduction polarization curve (ORR).

[0031] A three-electrode system was formed by using a glassy carbon electrode loaded with a single atomic layer of platinum as the working electrode, a reversible hydrogen electrode as the reference electrode, and a platinum wire electrode as the counter electrode. A cyclic voltammetry scan test was performed at a scan rate of 20 mV / s in the potential range of 0-1.2 V using 0.1 M HClO4 saturated with Ar as the electrolyte solution. The results are shown in Figure 2. Figure 5 As shown; cyclic voltammetry scanning technology was selected, and 0.1 M HClO4 saturated with O2 was used as the electrolyte solution. Cyclic voltammetry scanning test was performed in the potential range of 0~1.2 V at a scanning speed of 20 mV / s and a rotating disk electrode speed of 1600 rpm. The results are shown in Figure 6 shown. Figure 5 Figure 3 is the CV polarization curve of the Pt monolayer catalyst. It is observed that both in the H adsorption and desorption zone (0-0.3 V) and at the reduction peak around 0.9 V, it is obviously similar to the CV curve of the Pt / C catalyst, indicating that the Pt atoms are coated on the surface of the copper-carbon nanocomposite material. Figure 6 ORR polarization curve of Pt monolayer catalyst.

[0032] Figure 7 H2 / Air membrane electrode polarization curve of Pt monolayer catalyst at 100% relative humidity.

[0033] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in the field. Although the illustrative specific embodiments of the present invention are described above to facilitate the understanding of the present invention by the technical personnel in the field, it should be clear that the present invention is not limited to the scope of the specific embodiments. For the ordinary technical personnel in the field, as long as various changes are within the spirit and scope of the present invention defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A method for preparing a dense platinum monoatomic layer catalyst for a fuel cell cathode, characterized in that: The following steps are involved: Step 1, mixing potassium chloroplatinite and sulfuric acid to obtain a chloroplatinic acid solution; Step 2, mixing copper and carbon to obtain a copper-carbon mixture; Step 3, the copper-carbon mixture is uniformly mixed with the chloroplatinic acid solution, and stirred while heating to perform single atomic layer replacement of Pt, and a platinum single atomic layer catalyst is obtained after drying.

2. The method for preparing a dense platinum monoatomic layer catalyst for a fuel cell cathode according to claim 1, characterized in that: The dosage ratio of potassium chloroplatinite and sulfuric acid in step 1 is 1:

10.

3. The method for preparing a dense platinum monoatomic layer catalyst for a fuel cell cathode according to claim 1, characterized in that: The ratio of copper to carbon in step 2 is 1:9 to 8:

2.

4. The method for preparing a dense platinum monoatomic layer catalyst for a fuel cell cathode according to claim 1, characterized in that: The usage ratio of the copper-carbon mixture to the chloroplatinic acid solution is 1:10 to 10:

1.

5. The method for preparing a dense platinum monoatomic layer catalyst for a fuel cell cathode according to claim 1, characterized in that: The heating and stirring in step 3 specifically includes: the heating temperature is 30° C. to 60° C., the stirring speed is 300 rpm to 500 rpm, or the ultrasonic time is greater than 3 h.

6. A dense platinum monoatomic layer catalyst for a fuel cell cathode obtained by the preparation method according to any one of claims 1 to 5.

7. A fuel cell cathode dense platinum monoatomic layer catalyst according to claim 6, characterized in that: In the catalyst, platinum is loaded on the copper surface to form lattice stripes.

8. Use of a dense platinum monoatomic layer catalyst for a fuel cell cathode prepared by the preparation method according to any one of claims 1 to 5 in a membrane electrode system.

9. The use of a dense platinum monoatomic layer catalyst for a fuel cell cathode in a membrane electrode system according to claim 8, characterized in that: The catalyst suspension is transferred to the electrode surface using a hanging drop method; or the catalyst suspension is evenly sprayed onto the surface of the ion exchange membrane or the gas diffusion layer.

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