CN116230972A - Monoatomically dispersed PtCo-N-C catalyst, and preparation method and application thereof - Google Patents

Monoatomically dispersed PtCo-N-C catalyst, and preparation method and application thereof Download PDF

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CN116230972A
CN116230972A CN202310163908.3A CN202310163908A CN116230972A CN 116230972 A CN116230972 A CN 116230972A CN 202310163908 A CN202310163908 A CN 202310163908A CN 116230972 A CN116230972 A CN 116230972A
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catalyst
ptco
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王雅宁
张坤
华文超
许开华
张子扬
杜柯
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GEM Co Ltd China
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/92—Metals of platinum group
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/92—Metals of platinum group
    • H01M4/925—Metals of platinum group supported on carriers, e.g. powder carriers
    • H01M4/926—Metals of platinum group supported on carriers, e.g. powder carriers on carbon or graphite
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    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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    • Y02E60/50—Fuel cells

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Abstract

The invention provides a single-atom dispersed PtCo-N-C catalyst, a preparation method and application thereof, wherein Pt and Co in the catalyst are in single-atom dispersed level respectively; the preparation method comprises the following steps: (1) Mixing zinc salt, cobalt salt and solvent A to obtain a first solution; (2) mixing the organic ligand with solvent B to obtain a second solution; (3) Mixing the first solution and the second solution for standing reaction, and obtaining metal organic matters after solid-liquid separation; (4) Roasting the metal organic matters to obtain monoatomically dispersed Co-N-C; (5) And freezing the platinum precursor solution to a solid state, obtaining single-atom dispersed Pt through the reduction of ultraviolet irradiation, and loading the Pt on Co-N-C by utilizing the electrostatic adsorption to obtain the PtCo-N-C catalyst. The preparation method simplifies the synthesis process, improves the catalytic activity and stability, and reduces the waste of bulk phase atoms in the nano particles.

Description

Monoatomically dispersed PtCo-N-C catalyst, and preparation method and application thereof
Technical Field
The invention belongs to the technical field of catalyst preparation, relates to a monoatomically dispersed catalyst, and in particular relates to a monoatomically dispersed PtCo-N-C catalyst, and a preparation method and application thereof.
Background
With the dramatic increase in limited fossil fuel consumption, serious air pollution and energy shortage problems have raised general attention worldwide, and the development of sustainable clean energy conversion technologies has been elusive. Proton Exchange Membrane Fuel Cells (PEMFCs) are a high-efficiency hydrogen energy conversion technology and have great application potential in the aspects of reducing carbon emission, relieving energy crisis and the like. Currently, the PEMFC cathodic oxygen reduction reaction is kinetically slow, requiring extensive use of an expensive and rare platinum-based catalyst, thus impeding its further large-scale commercial application.
In view of the above problems, the monoatomically dispersed metal-nitrogen-carbon (M-N-C) catalyst is a good substitute for Pt nanoparticle catalysts, with low cost, high activity, and other unique advantages such as: uniform active sites, high atom utilization and high intrinsic activity. However, the problem of complex synthesis process often exists in the preparation process of the monoatomic dispersion catalyst at present, and metal monoatomic sites obtained by synthesis are easily agglomerated into nano particles in the post-treatment and reaction processes, so that the structural stability of the nano particles is affected.
CN 111653792a discloses a method for synchronously preparing PtCo/Co-N-C catalyst, firstly homogenizing cobalt salt, zinc salt and ultrapure water, then adding 2-methylimidazole aqueous solution, stirring uniformly, then adding strong reducer aqueous solution for mixing reaction, finally adding platinum salt aqueous solution for mixing reaction, centrifuging the product, cleaning, drying, and annealing at high temperature in inert gas environment to obtain PtCo/Co-N-C catalyst. However, the catalyst obtained by the invention is a material with a PtCo nano particle structure loaded on a Co-N-C nano rod with a hollow structure, and is not in a monoatomic dispersion level, and the catalytic activity and stability still need to be further improved.
Therefore, how to provide a single-atom dispersed metal-nitrogen-carbon catalyst and a preparation method thereof, which can simplify the synthesis process, improve the catalytic activity and stability, and reduce the waste of bulk atoms in the nano particles, is an urgent problem to be solved by the current technicians in the field.
Disclosure of Invention
The invention aims to provide a single-atom dispersed PtCo-N-C catalyst, and a preparation method and application thereof.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a monoatomically dispersed PtCo-N-C catalyst, wherein Pt and Co in the PtCo-N-C catalyst are respectively in monoatomically dispersed grades.
The Pt and Co in the PtCo-N-C catalyst provided by the invention are in a single-atom dispersion level respectively, so that 100% of utilization rate of Pt and Co atoms is realized, waste of bulk phase atoms in nano particles is effectively reduced, half-wave potential and initial potential of the catalyst are obviously higher than those of commercial Pt/C catalysts, the catalyst has higher specific activity and mass activity, and the catalyst has excellent catalytic performance.
Preferably, the Pt loading in the PtCo-N-C catalyst is 1.0-10.0wt.%, e.g., but not limited to, 1.0wt.%, 2.0wt.%, 2.5wt.%, 3.0wt.%, 3.5wt.%, 4.0wt.%, 4.5wt.%, 5.0wt.%, 5.5wt.%, 6.0wt.%, 6.5wt.%, 7.0wt.%, 7.5wt.%, 8.0wt.%, 8.5wt.%, 9.0wt.%, 9.5wt.% or 10.0wt.%, other non-recited values within the range of values are equally applicable.
Preferably, the loading of Co in the PtCo-N-C catalyst is 1.0-10.0wt.%, e.g., but not limited to, 1.0wt.%, 2.0wt.%, 2.5wt.%, 3.0wt.%, 3.5wt.%, 4.0wt.%, 4.5wt.%, 5.0wt.%, 5.5wt.%, 6.0wt.%, 6.5wt.%, 7.0wt.%, 7.5wt.%, 8.0wt.%, 8.5wt.%, 9.0wt.%, 9.5wt.% or 10.0wt.%, other non-recited values within the range of values are equally applicable.
In a second aspect, the present invention provides a method for producing the PtCo-N-C catalyst according to the first aspect, the method comprising the steps of:
(1) Mixing zinc salt, cobalt salt and solvent A to obtain a first solution;
(2) Mixing the organic ligand and the solvent B to obtain a second solution;
(3) Mixing the first solution obtained in the step (1) and the second solution obtained in the step (2), standing for reaction, and carrying out solid-liquid separation to obtain a metal organic matter;
(4) Roasting the metal organic matter obtained in the step (3) to obtain monoatomic dispersed Co-N-C;
(5) Freezing the platinum precursor solution to a solid state, obtaining the monoatomic dispersed Pt through the reduction of ultraviolet irradiation, and loading the Pt on the Co-N-C obtained in the step (4) by utilizing the electrostatic adsorption effect to obtain the monoatomic dispersed PtCo-N-C catalyst.
Wherein, the steps (1) and (2) are not in sequence.
The method provided by the invention takes the monoatomic dispersed Co-N-C material obtained by pyrolysis of the metal organic as a precursor, and prepares the monoatomic PtCo-N-C catalyst by an ultraviolet light reduction method, so that the method has the advantages of simple process flow, low preparation cost, high operability and potential of large-scale industrial production and application.
Preferably, the zinc salt of step (1) comprises zinc nitrate and the cobalt salt comprises cobalt nitrate.
Preferably, zn in the first solution of step (1) 2+ The concentration of (C) is 0.4-5mol/L, for example, 0.4mol/L, 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, 2.5mol/L, 3mol/L, 3.5mol/L, 4mol/L, 4.5mol/L or 5mol/L, and more preferably 0.4-2mol/L, but the present invention is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned values are applicable.
Preferably, n (Zn) in the first solution of step (1) 2+ ):n(Co 2+ ) 15:1, for example, may be 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1, but is not limited to the recited valuesOther non-enumerated values within the scope are equally applicable.
In the synthesis process of the metal organic framework structure, zn 2+ And Co 2+ Can be used as metal nodes to connect organic ligands to form a framework. Wherein Zn is 2+ Is mainly used for dispersing Co 2+ To enable adjacent Co in the framework 2+ The distance between the two components is increased, so that the agglomeration phenomenon is effectively prevented in the subsequent heat treatment process, and the single-atom Co always exists. In the synthesis process, when n (Zn 2+ ):n(Co 2+ ) Can realize pyrolysis to obtain the Co-N-C catalyst with complete monoatomic dispersion after being heated to be more than or equal to 15:1, if N (Zn) 2+ ):n(Co 2+ ) Partial Co nanoparticles may be present in < 15:1, affecting catalyst performance.
Preferably, the organic ligand of step (2) comprises 2-methylimidazole.
Preferably, the concentration of the organic ligand in the second solution in step (2) is 0.5-10mol/L, for example, but not limited to, 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, 2.5mol/L, 3mol/L, 3.5mol/L, 4mol/L, 4.5mol/L, 5mol/L, 5.5mol/L, 6mol/L, 6.5mol/L, 7mol/L, 7.5mol/L, 8mol/L, 8.5mol/L, 9mol/L, 9.5mol/L or 10mol/L, and other non-enumerated values within this range are equally applicable.
Preferably, the solvent a of step (1) and the solvent B of step (2) each independently comprise any one or a combination of at least two of methanol, deionized water, or dimethylformamide, typically but not limited to, a combination of methanol and deionized water, a combination of deionized water and dimethylformamide, a combination of methanol and dimethylformamide, or a combination of methanol, deionized water and dimethylformamide.
The temperature of the standing reaction in the step (3) is preferably 20 to 40 ℃, and may be, for example, 20 ℃, 22 ℃, 24 ℃, 26 ℃, 28 ℃, 30 ℃, 32 ℃, 34 ℃, 36 ℃, 38 ℃ or 40 ℃, but is not limited to the values listed, and other values not listed in the range are equally applicable.
Preferably, the time of the standing reaction in the step (3) is 20-30h, for example, 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h or 30h, but not limited to the recited values, and other non-recited values within the range are equally applicable.
Preferably, the metal organic obtained in the step (3) is washed and dried sequentially.
Preferably, the wash solution employed for the wash comprises any one or a combination of at least two of methanol, deionized water, or dimethylformamide, typically but not limited to a combination of methanol and deionized water, a combination of deionized water and dimethylformamide, a combination of methanol and dimethylformamide, or a combination of methanol, deionized water, and dimethylformamide.
Preferably, the drying includes vacuum drying, and the temperature of the vacuum drying is 20-40 ℃, for example, 20 ℃, 22 ℃, 24 ℃, 26 ℃, 28 ℃, 30 ℃, 32 ℃, 34 ℃, 36 ℃, 38 ℃ or 40 ℃, but is not limited to the recited values, and other non-recited values within the range of the values are equally applicable.
Preferably, the baking treatment of step (4) is performed in a quartz tube, and a protective gas is introduced into the quartz tube.
Preferably, the protective gas comprises any one of nitrogen, helium or argon.
The temperature of the baking treatment in the step (4) is preferably 600 to 900 ℃, and may be 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃ or 900 ℃, for example, but the method is not limited to the listed values, and other values not listed in the range are applicable.
In the invention, the purpose of the roasting treatment is to realize the conversion of metal organic matters from a framework precursor to a Co-N-C structure, and the temperature range is critical. If the temperature of the roasting treatment is lower than 600 ℃, the metal Zn cannot be completely gasified, so that the performance of the subsequent catalyst is affected; if the temperature of the calcination treatment is higher than 900 ℃, the metal Co is easy to agglomerate and sinter at high temperature, and then the monoatomically dispersed Co-N-C cannot be obtained.
Preferably, the time of the calcination treatment in step (4) is 1 to 5 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours or 5 hours, but not limited to the recited values, and other non-recited values within the range are equally applicable.
Preferably, the platinum precursor in the platinum precursor solution of step (5) comprises chloroplatinic acid and/or ammonium chloroplatinic acid.
Preferably, the solvent in the platinum precursor solution of step (5) comprises deionized water.
Preferably, the freezing of step (5) is performed in liquid nitrogen.
Preferably, the wavelength of the ultraviolet light in step (5) is 300-400nm, for example, 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, 370nm, 380nm, 390nm or 400nm, but not limited to the recited values, and other non-recited values within the range are equally applicable.
Preferably, the time of the ultraviolet irradiation in the step (5) is 2-20h, for example, 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h or 20h, but not limited to the recited values, and other non-recited values in the range of the values are equally applicable.
As a preferred technical solution of the second aspect of the present invention, the preparation method includes the following steps:
(1) Mixing zinc nitrate, cobalt nitrate and a solvent A to obtain a first solution; the solvent A comprises any one or a combination of at least two of methanol, deionized water and dimethylformamide; zn in the first solution 2+ Is 0.4-2mol/L and satisfies n (Zn) 2+ ):n(Co 2+ )≥15:1；
(2) Mixing 2-methylimidazole with the solvent B to obtain a second solution; the solvent B comprises any one or a combination of at least two of methanol, deionized water and dimethylformamide; the concentration of the 2-methylimidazole in the second solution is 0.5-10mol/L;
(3) Mixing the first solution obtained in the step (1) and the second solution obtained in the step (2), standing for 20-30 hours at 20-40 ℃, carrying out solid-liquid separation to obtain metal organic matters, washing and drying the obtained metal organic matters in sequence, wherein washing liquid adopted in washing comprises any one or a combination of at least two of methanol, deionized water and dimethylformamide, and drying comprises vacuum drying at 20-40 ℃;
(4) Roasting the metal organic matters obtained in the step (3) in a quartz tube filled with protective gas at 600-900 ℃ for 1-5 hours to obtain monoatomic dispersed Co-N-C; the protective gas comprises any one of nitrogen, helium or argon;
(5) Freezing deionized water solution of chloroplatinic acid and/or ammonium chloroplatinate to be solid in liquid nitrogen, obtaining single-atom dispersed Pt through reduction of ultraviolet light with the wavelength of 300-400nm for 2-20h, and loading the Pt on Co-N-C obtained in the step (4) by utilizing electrostatic adsorption to obtain the single-atom dispersed PtCo-N-C catalyst.
Wherein, the steps (1) and (2) are not in sequence.
In a third aspect, the present invention provides the use of a PtCo-N-C catalyst according to the first aspect, including the field of fuel cells.
Preferably, the PtCo-N-C catalyst is used as a cathode catalyst for a fuel cell.
Compared with the prior art, the invention has the following beneficial effects:
(1) The Pt and Co in the PtCo-N-C catalyst provided by the invention are in a single-atom dispersion level respectively, so that 100% of utilization rate of Pt and Co atoms is realized, waste of bulk phase atoms in nano particles is effectively reduced, half-wave potential and initial potential of the catalyst are obviously higher than those of commercial Pt/C catalysts, the catalyst has higher specific activity and mass activity, and excellent catalytic performance;
(2) The method provided by the invention takes the monoatomic dispersed Co-N-C material obtained by pyrolysis of the metal organic as a precursor, and prepares the monoatomic PtCo-N-C catalyst by an ultraviolet light reduction method, so that the method has the advantages of simple process flow, low preparation cost, high operability and potential of large-scale industrial production and application.
Drawings
FIG. 1 is a high resolution transmission electron micrograph of monoatomically dispersed Co-N-C obtained by the method of preparation provided in example 1;
FIG. 2 is a high resolution transmission electron micrograph of a single atom dispersed PtCo-N-C catalyst obtained by the preparation method provided in example 1.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Example 1
The present example provides a monoatomically dispersed PtCo-N-C catalyst having a Pt loading of 5.0wt.%, and a Co loading of 5.0wt.%, and a method of preparing the same.
In this embodiment, the preparation method includes the following steps:
(1) Mixing zinc nitrate, cobalt nitrate and methanol to obtain a first solution; zn in the first solution 2+ Is 2mol/L and satisfies n (Zn) 2+ ):n(Co 2+ )＝20:1；
(2) Mixing 2-methylimidazole and methanol to obtain a second solution; the concentration of the 2-methylimidazole in the second solution is 5mol/L;
(3) Mixing the first solution obtained in the step (1) and the second solution obtained in the step (2), standing at 30 ℃ for 24 hours, filtering to obtain a metal organic matter, washing and drying the obtained metal organic matter in sequence, wherein the washing liquid adopted in the washing is methanol, and the drying is vacuum drying at 30 ℃;
(4) Roasting the metal organic matter obtained in the step (3) in a quartz tube filled with nitrogen for 3 hours at 750 ℃ to obtain monoatomic dispersed Co-N-C;
(5) Freezing deionized water solution of chloroplatinic acid to be solid in liquid nitrogen, obtaining monoatomic dispersed Pt through reduction of ultraviolet light with the wavelength of 350nm for 12 hours, and loading the Pt on Co-N-C obtained in the step (4) by utilizing electrostatic adsorption to obtain the monoatomic dispersed PtCo-N-C catalyst.
In this example, the high-resolution transmission electron micrograph of the monoatomically dispersed Co-N-C obtained in step (4) is shown in FIG. 1, and the high-resolution transmission electron micrograph of the monoatomically dispersed PtCo-N-C catalyst obtained in step (5) is shown in FIG. 2.
As can be seen from fig. 1 and 2: the Co-N-C and PtCo-N-C catalysts obtained in this example both reached the level of monoatomic dispersion of the metal element (bright spot in the figure).
Example 2
The present example provides a monoatomically dispersed PtCo-N-C catalyst having a Pt loading of 1.0wt.%, and a Co loading of 1.0wt.%, and a method of preparing the same.
In this embodiment, the preparation method includes the following steps:
(1) Mixing zinc nitrate, cobalt nitrate and deionized water to obtain a first solution; zn in the first solution 2+ Is 0.4mol/L and satisfies n (Zn) 2+ ):n(Co 2+ )＝15:1；
(2) Mixing 2-methylimidazole and deionized water to obtain a second solution; the concentration of the 2-methylimidazole in the second solution is 0.5mol/L;
(3) Mixing the first solution obtained in the step (1) and the second solution obtained in the step (2), standing for 30 hours at 20 ℃, filtering to obtain a metal organic matter, washing and drying the obtained metal organic matter in sequence, wherein the washing liquid adopted in the washing is deionized water, and the drying is vacuum drying at 20 ℃;
(4) Roasting the metal organic matters obtained in the step (3) in a quartz tube filled with helium for 5 hours at 600 ℃ to obtain monoatomic dispersed Co-N-C;
(5) Freezing deionized water solution of chloroplatinic acid to be solid in liquid nitrogen, obtaining monoatomic dispersed Pt through reduction of ultraviolet light with the wavelength of 300nm for 20 hours, and loading the Pt on Co-N-C obtained in the step (4) by utilizing electrostatic adsorption to obtain the monoatomic dispersed PtCo-N-C catalyst.
The Co-N-C and PtCo-N-C catalysts obtained in this example all achieve the level of monoatomic dispersion of the metal element, and the relevant photomicrographs are similar to those of example 1, and therefore are not described here.
Example 3
The present example provides a monoatomically dispersed PtCo-N-C catalyst having a Pt loading of 10.0wt.%, and a Co loading of 10.0wt.%, and a method of preparing the same.
In this embodiment, the preparation method includes the following steps:
(1) Mixing zinc nitrate, cobalt nitrate and dimethylformamide to obtain a first solution; zn in the first solution 2+ Is 5mol/L and satisfies n (Zn) 2+ ):n(Co 2+ )＝25:1；
(2) Mixing 2-methylimidazole and dimethylformamide to obtain a second solution; the concentration of the 2-methylimidazole in the second solution is 10mol/L;
(3) Mixing the first solution obtained in the step (1) and the second solution obtained in the step (2), carrying out standing reaction for 20 hours at 40 ℃, filtering to obtain metal organic matters, washing and drying the obtained metal organic matters in sequence, wherein the washing liquid adopted in the washing is dimethylformamide, and the drying is vacuum drying at 40 ℃;
(4) Roasting the metal organic matter obtained in the step (3) in a quartz tube filled with argon at 900 ℃ for 1h to obtain monoatomic dispersed Co-N-C;
(5) Freezing deionized water solution of ammonium chloroplatinite to be solid in liquid nitrogen, obtaining monoatomic dispersed Pt through reduction of ultraviolet light with the wavelength of 400nm for 2 hours, and loading the Pt on Co-N-C obtained in the step (4) by utilizing electrostatic adsorption to obtain the monoatomic dispersed PtCo-N-C catalyst.
The Co-N-C and PtCo-N-C catalysts obtained in this example all achieve the level of monoatomic dispersion of the metal element, and the relevant photomicrographs are similar to those of example 1, and therefore are not described here.
Example 4
This example provides a monoatomically dispersed PtCo-N-C catalyst and a method for producing the same except that N (Zn in step (1) 2+ ):n(Co 2+ ) The ratio is changed to 13:1, and the other steps and conditions are the same as those of the embodiment 1, so that the description is omitted here.
In this example, as compared with example 1, n (Zn 2+ ):n(Co 2+ ) Changing to below 15:1, results in a firstZn in solution 2+ Insufficient and ineffective dispersion of Co 2+ Further, some Co nanoparticles appear in Co-N-C and PtCo-N-C catalysts.
Example 5
The present embodiment provides a monoatomically dispersed PtCo-N-C catalyst and a preparation method thereof, wherein the preparation method is the same as that of embodiment 1 except that the temperature of the calcination treatment in step (4) is changed to 500 ℃, and the rest steps and conditions are the same as those of embodiment 1, so that no description is repeated here.
Compared with example 1, in this example, the roasting temperature is too low, so that the metal Zn cannot be completely gasified, and the catalyst contains the metal Zn, which affects the activity and stability of the catalyst.
Example 6
The present embodiment provides a monoatomically dispersed PtCo-N-C catalyst and a preparation method thereof, wherein the preparation method is the same as that of embodiment 1 except that the temperature of the calcination treatment in step (4) is changed to 1000 ℃, and the rest steps and conditions are the same as those of embodiment 1, so that no description is repeated here.
Compared with the embodiment 1, the embodiment has the advantages that the agglomeration and sintering of the metal Co are easy to occur due to the too high roasting temperature, and even the single-atom dispersed Co-N-C cannot be obtained, so that the performance of the catalyst is influenced.
The monoatomically dispersed PtCo-N-C catalysts obtained in examples 1-3 and a commercial Pt/C catalyst (Zhuang Xinmo Feng Hispec 4000) were selected for oxygen reduction testing, respectively, as follows:
the glassy carbon electrode is used as a working electrode, the platinum electrode is used as a counter electrode, the Ag/AgCl electrode is used as a reference electrode, and the catalyst loading capacity on the electrode is 3 mug Pt HClO at 0.1M 4 Linear scan testing (0.05-1.10 Vvs RHE,20 mV/s) was performed in solution and the electrochemical performance parameters of the PtCo-N-C catalysts obtained in examples 1-3 and commercial Pt/C catalysts are shown in Table 1 below.
TABLE 1
Figure BDA0004095206780000111
Figure BDA0004095206780000121
As can be seen from table 1: compared with commercial Pt/C catalysts, the PtCo-N-C catalysts obtained in examples 1-3 have higher initial potential and half-wave potential, and have higher mass activity, i.e. the use of PtCo-N-C catalysts can save more than 1/2 of the noble metal platinum under the same current density.
Therefore, pt and Co in the PtCo-N-C catalyst provided by the invention are in a single-atom dispersion level respectively, 100% of utilization rate of Pt and Co atoms is realized, waste of bulk phase atoms in nano particles is effectively reduced, half-wave potential and initial potential of the catalyst are obviously higher than those of commercial Pt/C catalysts, and the catalyst has higher specific activity, higher mass activity and excellent catalytic performance.
In addition, the method provided by the invention uses the monoatomic dispersed Co-N-C material obtained by pyrolysis of the metal organic as a precursor, and prepares the monoatomic PtCo-N-C catalyst by an ultraviolet light reduction method, so that the method has the advantages of simple process flow, low preparation cost, high operability and potential of large-scale industrial production and application.
The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.

Claims (10)

1. A monoatomically dispersed PtCo-N-C catalyst is characterized in that Pt and Co in the PtCo-N-C catalyst are respectively in monoatomically dispersed grades.
2. The PtCo-N-C catalyst of claim 1, wherein the Pt loading in the PtCo-N-C catalyst is 1.0-10.0wt.%;
preferably, the loading of Co in the PtCo-N-C catalyst is 1.0-10.0wt.%.
3. A method for producing the PtCo-N-C catalyst according to claim 1 or 2, characterized by comprising the steps of:
(1) Mixing zinc salt, cobalt salt and solvent A to obtain a first solution;
(2) Mixing the organic ligand and the solvent B to obtain a second solution;
(3) Mixing the first solution obtained in the step (1) and the second solution obtained in the step (2), standing for reaction, and carrying out solid-liquid separation to obtain a metal organic matter;
(4) Roasting the metal organic matter obtained in the step (3) to obtain monoatomic dispersed Co-N-C;
(5) Freezing the platinum precursor solution to a solid state, obtaining monoatomic dispersed Pt through the reduction of ultraviolet irradiation, and loading the Pt on the Co-N-C obtained in the step (4) by utilizing the electrostatic adsorption effect to obtain the monoatomic dispersed PtCo-N-C catalyst;
wherein, the steps (1) and (2) are not in sequence.
4. The method of claim 3 wherein the zinc salt of step (1) comprises zinc nitrate and the cobalt salt comprises cobalt nitrate;
preferably, zn in the first solution of step (1) 2+ The concentration of (C) is 0.4-5mol/L, more preferably 0.4-2mol/L;
preferably, n (Zn) in the first solution of step (1) 2+ ):n(Co 2+ )≥15:1；
Preferably, the organic ligand of step (2) comprises 2-methylimidazole;
preferably, the concentration of the organic ligand in the second solution of step (2) is 0.5-10mol/L;
preferably, the solvent a of step (1) and the solvent B of step (2) each independently comprise any one or a combination of at least two of methanol, deionized water or dimethylformamide.
5. The method according to claim 3 or 4, wherein the temperature of the standing reaction in step (3) is 20 to 40 ℃;
preferably, the time of the standing reaction in the step (3) is 20-30 hours;
preferably, the metal organic matters obtained in the step (3) are washed and dried in sequence;
preferably, the washing liquid used in the washing comprises any one or a combination of at least two of methanol, deionized water and dimethylformamide;
preferably, the drying comprises vacuum drying, and the temperature of the vacuum drying is 20-40 ℃.
6. The method according to any one of claims 3 to 5, wherein the baking treatment in step (4) is performed in a quartz tube, and a protective gas is introduced into the quartz tube;
preferably, the protective gas comprises any one of nitrogen, helium or argon;
preferably, the temperature of the roasting treatment in the step (4) is 600-900 ℃;
preferably, the roasting treatment in the step (4) is carried out for 1-5 hours.
7. The method of any one of claims 3-6, wherein the platinum precursor in the platinum precursor solution of step (5) comprises chloroplatinic acid and/or ammonium chloroplatinic acid;
preferably, the solvent in the platinum precursor solution of step (5) comprises deionized water;
preferably, the freezing of step (5) is performed in liquid nitrogen;
preferably, the wavelength of the ultraviolet irradiation in the step (5) is 300-400nm;
preferably, the time of the ultraviolet irradiation in the step (5) is 2-20h.
8. The preparation method according to any one of claims 3 to 7, characterized in that the preparation method comprises the steps of:
(1) Mixing zinc nitrate, cobalt nitrate and a solvent A to obtain a first solution; the solvent A comprises methanol, deionized water orAny one or a combination of at least two of dimethylformamide; zn in the first solution 2+ Is 0.4-2mol/L and satisfies n (Zn) 2+ ):n(Co 2+ )≥15:1；
(2) Mixing 2-methylimidazole with the solvent B to obtain a second solution; the solvent B comprises any one or a combination of at least two of methanol, deionized water and dimethylformamide; the concentration of the 2-methylimidazole in the second solution is 0.5-10mol/L;
(3) Mixing the first solution obtained in the step (1) and the second solution obtained in the step (2), standing for 20-30 hours at 20-40 ℃, carrying out solid-liquid separation to obtain metal organic matters, washing and drying the obtained metal organic matters in sequence, wherein washing liquid adopted in washing comprises any one or a combination of at least two of methanol, deionized water and dimethylformamide, and drying comprises vacuum drying at 20-40 ℃;
(4) Roasting the metal organic matters obtained in the step (3) in a quartz tube filled with protective gas at 600-900 ℃ for 1-5 hours to obtain monoatomic dispersed Co-N-C; the protective gas comprises any one of nitrogen, helium or argon;
(5) Freezing deionized water solution of chloroplatinic acid and/or ammonium chloroplatinate to be solid in liquid nitrogen, obtaining monoatomic dispersed Pt through reduction of ultraviolet light with the wavelength of 300-400nm for 2-20 hours, and loading the Pt on Co-N-C obtained in the step (4) by utilizing electrostatic adsorption to obtain the monoatomic dispersed PtCo-N-C catalyst;
wherein, the steps (1) and (2) are not in sequence.
9. Use of a PtCo-N-C catalyst according to claim 1 or 2, characterized in that the use comprises the field of fuel cells.
10. The use according to claim 9, characterized in that the PtCo-N-C catalyst is used as cathode catalyst for fuel cells.
CN202310163908.3A 2023-02-24 2023-02-24 Monoatomically dispersed PtCo-N-C catalyst, and preparation method and application thereof Pending CN116230972A (en)

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