Topological chiral semimetal catalyst for oxygen electro-catalysis as well as preparation method and application of topological chiral semimetal catalyst

Abstract

The invention provides a topological chiral semimetal catalyst for oxygen electrocatalysis and a preparation method and application thereof.The topological chiral semimetal catalyst is a supported catalyst and comprises a carrier, an active component and guest metal, the carrier is selected from one of Vulcan XC-72R, Vulcan XC-72, Ketjenblack and carbon nanotubes, the active component is Pt, and the guest metal is selected from one of Vulcan XC-72R, Vulcan XC-72, Ketjenblack and carbon nanotubes. The invention discloses a topological chiral semi-metal material with a space group of P213, the topological chiral semi-metal material comprises an active component and a guest metal, the active component is a carrier, the dispersion size of the active component in the carrier is 2-4 nm, the guest metal is selected from one or two of Ga, Al, Ba, Ge, Bi, Sb, Eu, Fe, Cr, Sr and Mg, and compared with the prior art, the topological chiral semi-metal material (PtGa, PtMg, PtAl, BaGePt, BiTePt, BiSbPt, EuGePt, FeSbPt, CrSbPt and SrGePt) with the space group of P213 shows excellent performance in the oxygen reduction reaction of a fuel cell cathode. Compared with the current advanced PtC catalyst, the precious metal content is low, the stability is good, the yield of the by-product H2O2 is only 0.5%, and the PtC catalyst has a good application prospect in oxygen electro-catalysis.

Description

Technical Field

[0001] The present invention relates to the technical field of electrocatalytic reactions, and in particular to a topological chiral semimetal catalyst for oxygen electrocatalysis, and a preparation method and application thereof. Background Art

[0002] Fuel cells play a pivotal role in the global energy transition to a sustainable and low-carbon energy system. These electrochemical devices, which convert hydrogen and oxygen directly into electricity and water, offer a variety of advantages that are in line with the goals of reducing greenhouse gas emissions, improving energy efficiency, and achieving energy diversification. One of the main advantages of fuel cells is their high efficiency, which can reach 60% in electricity conversion efficiency, and even higher when utilizing waste heat in combined heat and power (CHP) applications. This efficiency exceeds that of traditional combustion power generation, making fuel cells an attractive alternative energy source to reduce dependence on fossil fuels and mitigate climate change.

[0003] However, the performance and cost of fuel cells are largely affected by the cathode oxygen reduction reaction (ORR). The oxygen reduction reaction usually proceeds through two main pathways: one is to directly convert oxygen (O 2 ) is reduced to water (H 2 O) and the other is a more efficient four-electron pathway that produces hydrogen peroxide (H 2 O 2 ) as an intermediate product. The four-electron pathway is more energy efficient and produces fewer byproducts, so it is preferred.

[0004] At present, platinum (Pt) is still the benchmark catalyst for ORR. Since rare metals have significant spin-orbit coupling, this will effectively promote the four-electron process of ORR. The chiral Pt nanoparticles reported in the literature (PANS.119 (2022) e2202650119) have an oxygen reduction half-wave potential of 0.87V in alkaline electrolytes, which is higher than that of traditional commercial PtC catalysts. It has high chemical selectivity, but the mass activity is relatively low. On the other hand, the cost of single precious metal catalysts is high, which is not conducive to commercial applications. Alloying provides an effective strategy to reduce the amount of precious metals. The literature (Angew.Chem.62 (2023) e202304420) synthesized ordered mesoporous intermetallic compound Ga-Pt nanoparticles with a non-isostructural chiral cubic phase by a template method. Under alkaline conditions, the mass activity and specific activity of meso-i-PtGa were 0.0667A mg, respectively. Pt -1 and 2.53 mAcm -2 However, after ADT testing, the mass activity dropped by about 47%, and the preparation process was relatively complicated and the material synthesis cycle was long.

[0005] In summary, there are two problems with the chiral catalysts currently studied. One is that the noble metal content is high, resulting in high catalyst costs, which is not conducive to commercial applications. The second is that the preparation process is relatively complex and the material synthesis cycle is long, which is not conducive to large-scale production. It is worth noting that the electrolyte of the currently used proton exchange membrane fuel cell is acidic, and the chiral catalyst lacks catalytic performance verification under acidic conditions. Therefore, it is of great research significance to develop catalysts with low noble metal loading, high stability and simple preparation process and apply them to oxygen electrocatalysis. Summary of the invention

[0006] In order to solve the above-mentioned technical problems, the present invention provides a method for growing an intermetallic compound with a topological chiral structure on a highly conductive carbon support by a simple one-step annealing method, and utilizes the topological chiral structure material to produce an electron spin selectivity effect in an electrocatalytic system, thereby directly improving the electrocatalytic reaction efficiency and chemical selectivity.

[0007] The present invention provides a topological chiral semimetal catalyst for oxygen electrocatalysis. The topological chiral semimetal catalyst is a supported catalyst and comprises a carrier, an active component and a guest metal. The carrier is selected from one of Vulcan XC-72R, Vulcan XC-72, Ketjenblack and carbon nanotubes. The active component is Pt, and the dispersed size of the active component in the carrier is 2-4 nm. The guest metal is selected from one or two of Ga, Al, Ba, Ge, Bi, Sb, Eu, Fe, Cr, Sr and Mg.

[0008] Compared with the prior art, the space group designed by the present invention is P2 1 3 topological chiral semimetal materials (PtGa, PtMg, PtAl, BaGePt, BiTePt, BiSbPt, EuGePt, FeSbPt, CrSbPt, GeTePt, SrGePt) show excellent performance in the cathode oxygen reduction reaction of fuel cells. Compared with the current advanced PtC catalyst, it has a lower precious metal content, good stability, and the byproduct H 2 O 2 The yield is only 0.5%, which has good application prospects in oxygen electrocatalysis.

[0009] In some embodiments, in the topological chiral semimetal catalyst, the mass content of Pt is 10-20wt% of the mass of the carrier, and the mass ratio of Pt to the guest metal is 2:1-1:6.

[0010] In some embodiments, the topological chiral semimetal catalyst has a cubic crystal structure and a space group of P2 1 3.

[0011] The second object of the present invention is to provide a method for preparing a topological chiral semimetal catalyst, wherein the topological chiral semimetal catalyst is prepared by a one-step annealing method, and the preparation method comprises the following steps: S1, dissolving Pt salt and guest metal salt in ethylene glycol according to the mass ratio to obtain a mixed solution A; S2, dissolving the carrier in ethylene glycol to obtain a mixed solution B; S3, under rapid stirring, slowly adding the mixed solution A into the mixed solution B, immersing and then drying; S4. Under an inert gas environment, annealing treatment is performed to obtain a topological chiral semimetal catalyst.

[0012] Compared with the prior art, the present invention adopts a "one-step method" to simultaneously complete the alloying and ordering of the target material, simplifies the operation steps, and shortens the production cycle.

[0013] In some embodiments, in step S1, the Pt salt is selected from at least one of chloroplatinic acid, ammonium hexachloroplatinate, platinum acetylacetonate, platinum nitrate and platinum oxalate.

[0014] In some embodiments, in step S1, the guest metal salt is selected from one or two of Al salts, Ga salts, Sn salts, Ba salts, Ge salts, Bi salts, Sb salts, Eu salts, Fe salts, Cr salts, Sr salts, and Mg salts, and the Al salt is selected from at least one of aluminum nitrate, aluminum chloride, aluminum sulfate, sodium aluminate, and aluminum hydroxide; the Ga salt is selected from at least one of gallium nitrate, gallium chloride, gallium sulfate, gallium acetate, and gallium citrate; the Ba salt is selected from at least one of barium nitrate, barium chloride, barium sulfate, and barium acetate; the Ge salt is selected from at least one of germanium chloride, At least one of germanium oxide; the Bi salt is selected from at least one of bismuth chloride, bismuth nitrate, and bismuth sulfate; the Sb salt is selected from at least one of antimony chloride, antimony nitrate, and antimony sulfate; the Eu salt is selected from at least one of europium chloride, europium nitrate, and europium sulfate; the Fe salt is selected from at least one of ferric chloride, ferric nitrate, and ferric sulfate; the Cr salt is selected from at least one of chromium chloride, chromium nitrate, chromium sulfate, and chromium acetate; the Sr salt is selected from at least one of strontium chloride, strontium nitrate, and strontium sulfate; the Mg salt is selected from at least one of magnesium chloride, magnesium nitrate, and magnesium sulfate.

[0015] In some embodiments, the volume of ethylene glycol in step S1 is the same as the volume of ethylene glycol in step S2.

[0016] In some embodiments, in step S4, the inert gas is selected from one of argon, nitrogen and a hydrogen-argon mixture.

[0017] In some embodiments, in step S4, the annealing treatment includes a primary annealing treatment and a secondary annealing treatment, and the parameters of the primary annealing treatment are as follows: temperature is 300-400°C, and time is 0.5-1h; the parameters of the secondary annealing treatment are as follows: temperature is 500-600°C, and time is 15-20min.

[0018] The third object of the present invention is to provide an application of a topological chiral semimetal catalyst in the cathode redox reaction of a fuel cell.

[0019] The topological chiral semimetal catalyst of the present invention is applied to the cathode redox reaction of a fuel cell, and has good stability within the reaction temperature range of 400 to 700° C. (preferably 500° C.), and the nanoparticles have good dispersibility within the range of 0.25 to 1 hour (preferably 0.25 hour) of heat preservation.

[0020] Compared with the prior art, the Pt loading of the topological chiral structure material constructed by the present invention is relatively low, with a mass fraction of 10%, uniformly dispersed with an average particle size of 2-4 nm, an ORR half-wave potential of 0.91 V, and a mass activity and specific activity of up to 1.17 Amg Pt -1 and 4.08 mA cm -2 , byproduct H 2 O 2 The yield is only 0.5%, which has good application prospects in oxygen electrocatalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is an X-ray diffraction pattern of PtGa, a topological chiral semimetal prepared in Example 1 of the present invention; Figure 2 1 is a linear sweep voltammetry comparison diagram (LSV) of the topological chiral semimetal PtGa prepared in Example 1 of the present invention and a commercial platinum-carbon catalyst; Figure 3 This is a comparison chart of the mass activity (MA) and specific activity (SA) of the topological chiral semimetal PtGa prepared in Example 1 of the present invention and a commercial platinum-carbon catalyst; Figure 4 1 is a cyclic voltammetry comparison diagram (CV) of the topological chiral semimetal PtGa prepared in Example 1 of the present invention and a commercial platinum-carbon catalyst; Figure 5 is a transmission electron microscope image (TEM) of the topological chiral semimetal PtGa prepared in Example 2 of the present invention; Figure 6 is the ORR electron transfer number and H of the topological chiral semimetal PtGa prepared in Example 1 of the present invention and the commercial platinum carbon catalyst 2 O 2 Yield comparison chart; Figure 7 It is a comparison chart of circular dichroism (CD) of the topological chiral semimetal PtGa prepared in Example 1 of the present invention and a commercial platinum-carbon catalyst. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation method and typical parameters of the present invention, and are not used to limit the parameter range described in the present invention. Reasonable changes derived therefrom are still within the scope of protection of the claims of the present invention.

[0023] It should be noted that the endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this article.

[0024] Unless otherwise defined, all terms, symbols and other scientific terms used herein are intended to have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. In some cases, terms with conventionally understood meanings are defined herein for the purpose of clarification or ease of reference, and such definitions herein should not be construed as indicating significant differences from conventional understandings in the art. The technical methods described or cited herein are generally well understood by those skilled in the art and are adopted by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents and instruments is carried out in accordance with the protocols and parameters given by the manufacturer.

[0025] The technical effects of the present invention are described below in conjunction with specific embodiments.

[0026] It is worth mentioning that in the specific embodiment of the present invention, in a five-hole three-electrode electrolytic cell, a rotating disk electrode (RRDE) with a diameter of 5 mm is used as the working electrode, Ag / AgCl is used as the reference electrode, and a stone mill rod is used as the counter electrode. The electrolyte is 0.1 MHClO 4 , the electrochemical active area of ​​the material is tested by cyclic voltammetry (CV), and the polarization curve of the material is tested by linear sweep voltammetry (LSV). The RRDE platinum ring current is tested to calculate the number of electron transfers and the yield of by-products in the reaction system. The circular dichroism (CD) spectrum is used to test the chiral optical activity of the target material.

[0027] Example 1

[0028] This embodiment provides a topological chiral semimetal PtGa, which is prepared by the following steps: 40 mg H 2 PtCl 6 -6H 2 O and 50 mg Ga(NO 3 ) 3 -xH 2 O was dissolved in 2 ml of ethylene glycol to form solution I. At the same time, 40 mg of Vulcan XC-72 was dissolved in 2 ml of ethylene glycol to form solution II. Both solutions were ultrasonically treated for 1 hour. Subsequently, solution I was slowly added to solution II under vigorous stirring. The resulting mixture was dried in an oven at 80 °C, and the resulting precursor powder was collected for further processing. The precursor powder was heated in H 2 The PtGa alloy was annealed at 300 °C for 1 hour in a / Ar atmosphere. Afterwards, the PtGa alloy was heated at 500 °C in H 2 The second annealing is carried out in a / Ar atmosphere for 20 minutes to generate an ordered PtGa intermetallic compound, and then the obtained intermetallic compound is washed and dried.

[0029] The topological chiral semimetal PtGa obtained in this example was subjected to X-ray diffraction, and the results are as follows: Figure 1 As shown, the data indicate that Pt and Ga atoms are arranged in an orderly manner in the lattice rather than randomly distributed, corresponding to the characteristic peaks of the cubic crystal system.

[0030] In a serum bottle, 2 mg of PtGa, the topological chiral semimetal obtained in this example, was dissolved in 0.5 mL of a 1:9 water / ethanol mixture. A 5 μL aliquot of 5% Nafion solution was added as a proton conductor and crosslinker. The mixture was ultrasonically dispersed for 30 minutes to form a uniform ink. Electrochemical oxygen reduction reaction (ORR) measurements were performed at 25 °C using a three-electrode system. The system consisted of a rotating disk electrode (RDE, 0.196 cm²) connected to a Metrohm Autolab electrochemical workstation, a carbon rod as a counter electrode, and an Ag / AgCl electrode as a reference electrode. All potentials were referenced to a reversible hydrogen electrode (RHE). Subsequently, 20 μL of the prepared ink was deposited on the RDE and allowed to dry at room temperature. In O 2 Saturated 0.1 M HClO 4 The ORR polarization linear sweep voltammetry (LSV) curves were recorded in the solution with a potential range of 0.2–1.05 V, an electrode rotation speed of 1600 rpm, and a scan rate of 10 mV s -1 The results are as follows Figure 2 As shown, the half-wave potential of PtGa is 0.91V. Figure 3The results show the mass activity and specific activity of PtGa / C and commercial PtC at 0.85 V. 2 Saturated 0.1M HClO 4 The linear sweep voltammetry curves were measured in solution and the background current was subtracted. The cyclic voltammetry (CV) curves were performed in the potential range of 0.2-1.1 V and the scan rate was 100 mV s -1 The results are as follows Figure 4 As shown, the electrochemical active area of ​​PtGa is 28.7 m² g Pt -1 .

[0031] RRDE test loop current, the result is as follows Figure 6 As shown, it is calculated that the number of electron transfers of PtGa is about 4, H 2 O 2 The yield is about 0.5%. The chiral optical activity of the target material was tested by circular dichroism (CD). Figure 7 As shown in Figure 2, a clear CD signal was observed for PtGa in the range of 200-300 nm, indicating that PtGa has an asymmetric center or plane and confirming that PtGa is a left-handed substance.

[0032] Example 2 This embodiment provides a topological chiral semimetal PtGa, which is prepared by the following steps: 40 mg H 2 PtCl 6 -6H 2 O and 50 mg Ga(NO 3 ) 3 -xH 2 O was dissolved in 2 ml of ethylene glycol to form solution I; at the same time, 40 mg of Vulcan XC-72 was dissolved in 2 ml of ethylene glycol to form solution II. Both solutions were ultrasonically treated for 1 hour. Subsequently, solution I was gradually added to solution II under vigorous stirring. The resulting mixture was dried in an oven at 80 °C, and the resulting precursor powder was collected for further processing; The precursor powder was heated in H 2 The PtGa alloy was annealed at 300 °C for 1 h in a / Ar atmosphere. Afterwards, the PtGa alloy was heated at 600 °C in a H 2 The second annealing is carried out in a / Ar atmosphere for 15 minutes to generate an ordered PtGa intermetallic compound, and then the obtained intermetallic compound is washed and dried.

[0033] The topological chiral semimetal PtGa prepared in this embodiment was observed by transmission electron microscopy (TEM), and its morphology is as follows: Figure 5 As shown, from Figure 5It can be seen that the nanoparticles are evenly distributed on the carbon support.

[0034] Example 3 This embodiment provides a topological chiral semimetal PtAl, which is different from Embodiment 1 only in that the guest metal salt in this embodiment is aluminum nitrate, and the rest is the same as Embodiment 1 and will not be described again.

[0035] Example 4 This embodiment provides a topological chiral semimetal PtMg, which is different from Embodiment 1 only in that the guest metal salt in this embodiment is magnesium chloride, and the rest is the same as Embodiment 1 and will not be described again.

[0036] Example 5 This embodiment provides a topological chiral semimetal PtGa, which is different from Embodiment 1 only in that the carrier in this embodiment is Cabot Vulcan XC-72R, and the rest is the same as Embodiment 1, which will not be described again.

[0037] Example 6 This embodiment provides a topological chiral semimetal PtGa, which is different from Embodiment 1 only in that the carrier in this embodiment is a carbon nanotube, and the rest is the same as Embodiment 1 and will not be described again.

[0038] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A topological chiral semimetal catalyst for oxygen electrocatalysis, characterized in that: The topological chiral semimetal catalyst is a supported catalyst and includes a carrier, an active component and a guest metal. The carrier is selected from one of Vulcan XC-72R, Vulcan XC-72, Ketjenblack and carbon nanotubes. The active component is Pt, and the dispersed size of the active component in the carrier is 2-4 nm. The guest metal is selected from one or two of Ga, Al, Ba, Ge, Bi, Sb, Eu, Fe, Cr, Sr and Mg.

2. The topological chiral semimetal catalyst for oxygen electrocatalysis according to claim 1, characterized in that: In the topological chiral semimetal catalyst, the mass content of Pt is 10-20wt% of the mass of the carrier, and the mass ratio of Pt to the guest metal is 2:1-1:

6.

3. The topological chiral semimetal catalyst for oxygen electrocatalysis according to claim 1, characterized in that: The topological chiral semimetal catalyst has a crystal structure of cubic system and a space group of P213.

4. A method for preparing a topological chiral semimetal catalyst as claimed in any one of claims 1 to 3, characterized in that: The topological chiral semimetal catalyst is prepared by a one-step annealing method, and the preparation method comprises the following steps: S1, dissolving Pt salt and guest metal salt in ethylene glycol according to the mass ratio to obtain a mixed solution A; S2, dissolving the carrier in ethylene glycol to obtain a mixed solution B; S3, under rapid stirring, slowly adding the mixed solution A into the mixed solution B, immersing and then drying; S4. Under an inert gas environment, annealing treatment is performed to obtain a topological chiral semimetal catalyst.

5. The method for preparing a topological chiral semimetal catalyst according to claim 4, characterized in that: In the step S1, the Pt salt is selected from at least one of chloroplatinic acid, ammonium hexachloroplatinate, platinum acetylacetonate, platinum nitrate and platinum oxalate.

6. The method for preparing a topological chiral semimetal catalyst according to claim 4, characterized in that: In step S1, the guest metal salt is selected from one or two of Al salt, Ga salt, Ba salt, Ge salt, Bi salt, Sb salt, Eu salt, Fe salt, Cr salt, Sr salt, and Mg salt, and the Al salt is selected from at least one of aluminum nitrate, aluminum chloride, aluminum sulfate, sodium aluminate, and aluminum hydroxide; the Ga salt is selected from at least one of gallium nitrate, gallium chloride, gallium sulfate, gallium acetate, and gallium citrate; the Ba salt is selected from at least one of barium nitrate, barium chloride, barium sulfate, and barium acetate; the Ge salt is selected from at least one of germanium chloride and germanium oxide. One; the Bi salt is selected from at least one of bismuth chloride, bismuth nitrate, and bismuth sulfate; the Sb salt is selected from at least one of antimony chloride, antimony nitrate, and antimony sulfate; the Eu salt is selected from at least one of europium chloride, europium nitrate, and europium sulfate; the Fe salt is selected from at least one of ferric chloride, ferric nitrate, and ferric sulfate; the Cr salt is selected from at least one of chromium chloride, chromium nitrate, chromium sulfate, and chromium acetate; the Sr salt is selected from at least one of strontium chloride, strontium nitrate, and strontium sulfate; the Mg salt is selected from at least one of magnesium chloride, magnesium nitrate, and magnesium sulfate.

7. The method for preparing a topological chiral semimetal catalyst according to claim 4, characterized in that: In step S4, the inert gas is selected from one of argon, nitrogen and a hydrogen-argon mixture.

8. The method for preparing a topological chiral semimetal catalyst according to claim 4, characterized in that: In step S4, the annealing treatment includes primary annealing treatment and secondary annealing treatment. The parameters of the primary annealing treatment are as follows: temperature is 300-400°C, time is 0.5-1h; the parameters of the secondary annealing treatment are as follows: temperature is 500-600°C, time is 15-20min.

9. Use of the topological chiral semimetal catalyst as claimed in any one of claims 1 to 3 in a cathode redox reaction of a fuel cell.

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