High-density Fe-based Pt monatomic alloy catalyst and preparation method thereof

Abstract

The invention discloses a high-density Fe-based Pt monatomic alloy catalyst which is characterized by comprising Fe nanoparticles and Pt monatomic loaded on the surfaces of the Fe nanoparticles, the atomic proportion of the Pt monatomic is close to 33%, and the proportion is the percentage of the number of the Pt monatomic on the surface to the total number of the Fe and platinum atoms on the surface; a preparation method of a high-density Fe-based Pt monatomic alloy catalyst comprises the following steps: selecting different substrate materials and carrying out pretreatment, then depositing Fe target materials on the surfaces of the different substrate materials to form Fe nanoparticle layers, then depositing Pt target materials on the surfaces of the Fe nanoparticle layers to increase loads, and finally preparing the high-density Fe-based Pt monatomic alloy catalyst. The preparation method comprises the following steps: sequentially loading Fe nano-particle layers and Pt single atoms on different substrates to obtain a complete structure, and carrying out corresponding vacuum annealing treatment to finally obtain the catalyst prepared under different parameters. According to the catalyst and the preparation method thereof, the maximum exposure of noble metal Pt atoms on the surface of the catalyst and the improvement of the catalytic performance are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic materials, and in particular to a high-density Fe-based Pt single-atom alloy catalyst and a preparation method thereof. Background Art

[0002] In recent years, alloying and single-atomization have provided favorable approaches for achieving low-cost and efficient utilization of Pt-based catalysts. However, alloy catalysts usually have numerous configurations, making it difficult to distinguish the coordination environment of the optimal active sites. Improving performance through theoretical simulations is relatively difficult. At the same time, catalytically active atoms are not completely distributed on the surface, and the atomic utilization of precious metals is low. Therefore, single-atom catalysts that load isolated metal atoms on substrates have been proposed. This not only maximizes the utilization of active atoms but also greatly increases the selectivity for target products. However, single-atom catalysts face bottlenecks such as low metal loading and poor high-temperature stability. The regulation of their intrinsic activity is basically dependent on the substrate, and it is difficult to specifically adjust the electronic structure of the active metal. Inspired by the advantages and disadvantages of alloying and single-atomization, single-atom alloy catalysts that highly disperse catalytically active metal atoms on the surface of another metal matrix have been proposed and widely used in various catalytic reactions. Single-atom alloy catalysts have both the high atomic utilization and high selectivity of single-atomization and the synergistic effect and stability of alloying, and have quickly become a new frontier in materials science and catalysis.

[0003] A search revealed Chinese patent literature that discloses a copper-cobalt single-atom alloy catalyst, its preparation method, and application (Announcement No. CN118186483B). The copper-cobalt single-atom alloy catalyst comprises copper nanoparticles and single cobalt atoms supported on the surface of the copper nanoparticles. By loading isolated cobalt atoms on the copper nanoparticles, the electronic state of the copper atoms is adjusted, causing them to change their adsorption configuration for the carbon monoxide intermediate, making it easier to convert it to methane. At the same time, the addition of single-atom cobalt promotes the dissociation and activation of water, providing the required protons for the deep reduction of carbon monoxide. This results in high selectivity and activity for converting carbon dioxide to methane, providing a new approach for the efficient conversion and utilization of carbon dioxide to a certain extent. However, the following deficiencies remain:

[0004] This single-atom alloy catalyst and its preparation method and application adopt the wet chemical path of "copper salt + cobalt salt + tannic acid reacting in ethylene glycol and then reducing", which relies on the uniform mixing of precursors in the solution. However, cobalt salt is prone to form local concentration differences in the solution, resulting in an increased tendency to agglomerate during single-atom nucleation, and the kinetics of its reduction process is difficult to accurately control, which may cause uneven deposition of cobalt atoms on the surface of copper nanoparticles. In addition, this single-atom alloy catalyst and its preparation method and application have insufficient anchoring ability of the copper carrier, and the interaction between the d-orbital electronic configuration of copper and cobalt is mainly metallic bond with weak bond energy. According to the theory of soft and hard acids and bases, the coordination stability of Cu and Co is poor, resulting in the cobalt single atoms being easy to migrate and agglomerate under high temperature or reaction conditions, easier to disperse, and having poor performance. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-density Fe-based Pt single-atom alloy catalyst and a preparation method thereof, so as to solve the problem raised in the above background technology that the coverage of catalytically active atoms on the surface of most single-atom alloy catalysts is low, so that their activity needs to be improved.

[0006] To this end, the present invention provides a high-density Fe-based Pt single-atom alloy catalyst, which is characterized by comprising Fe nanoparticles and Pt single atoms loaded on the surface of the Fe nanoparticles, wherein the atomic fraction of the Pt single atoms is close to 33%, which is the percentage of the number of surface Pt single atoms to the total number of surface iron and platinum atoms; the Pt single atoms are loaded on the surface of the Fe nanoparticles at this ratio, thereby avoiding the agglomeration and waste of Pt in traditional alloy catalysts, maximizing the utilization efficiency of single-atom active sites, and significantly reducing the amount of precious metal Pt, thereby reducing the preparation cost.

[0007] A method for preparing a high-density Fe-based Pt single-atom alloy catalyst specifically comprises the following steps:

[0008] S1. Select nickel foam as the substrate and cut it into 1cm 2 The square was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, blown dry with nitrogen, and then placed in a magnetron sputtering instrument;

[0009] S2. The Fe target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 2 h, and the argon flow was set to 0.2 Pa. The Pt target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 10 s, and the argon flow was set to 0.2 Pa.

[0010] S3. Take out the sample, put it into a quartz tube, and perform vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C. to obtain the product of the present invention.

[0011] Preferably, in the step S1, nickel foam is selected as the substrate and cut into pieces of 1 cm in size. 2 The squares were ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, dried with nitrogen, and then placed in a magnetron sputtering instrument. The specific steps are as follows: nickel foam was selected as the substrate material, and its high specific surface area and excellent conductivity were used to provide more attachment sites for the subsequent deposition of Fe nanoparticles and Pt single atoms, which played a good supporting role in the catalytic reaction. The cut nickel foam blocks were placed in acetone, ethanol, and deionized water in turn, and ultrasonically cleaned for 10 minutes each. Acetone removed organic impurities such as oil on the surface of the nickel foam, and ethanol further cleaned the residual acetone and some water-soluble impurities. Deionized water was used to thoroughly wash away the residual detergent and other tiny particles of impurities. After cleaning, the nickel foam is blown dry with nitrogen to remove residual moisture on the surface and prevent moisture from interfering with the subsequent magnetron sputtering process. The dried nickel foam is then placed in a magnetron sputtering instrument to prepare for metal deposition. The nickel foam has a three-dimensional porous structure and a large specific surface area, which provides abundant loading sites for Fe nanoparticles and Pt single atoms. The good conductivity of metallic nickel is conducive to charge transfer and improves the kinetics of the catalytic reaction. At the same time, magnetron sputtering technology can accurately control the deposition thickness and uniformity of Fe and Pt, ensuring that Pt is dispersed in the form of single atoms rather than agglomerated. Annealing treatment promotes the interfacial interaction between Fe nanoparticles and Pt single atoms, enhancing the structural stability of the catalyst.

[0012] Preferably, in the step S2, the Fe target is placed in a magnetron sputtering apparatus and evacuated for sputtering, the sputtering gas is argon, the sputtering time is 2 hours, and the argon flow is set to 0.2 Pa; the Pt target is placed in a magnetron sputtering apparatus and evacuated for sputtering, the sputtering gas is argon, the sputtering time is 10 seconds, and the argon flow is set to 0.2 Pa. The specific steps are:

[0013] (1) Deposition of Fe nanoparticle layer: Place Fe target with purity ≥99.95% in magnetron sputtering instrument, and then evacuate the magnetron sputtering instrument to reduce the internal pressure of the magnetron sputtering instrument to the background vacuum degree ≤10 -4 Pa, and then introduce argon gas with a purity of ≥99.99% as sputtering gas, and adjust the gas pressure to 0.2 Pa. Argon ions are accelerated to collide with the Fe target surface under the action of the electric field, so that Fe atoms are sputtered from the target surface and deposited on the substrate surface. The sputtering time is set to 2 hours. During this time, Fe atoms continue to deposit on the substrate surface, gradually forming an Fe nanoparticle layer with a certain thickness and structure;

[0014] (2) Loading of Pt Single Atoms: After the Fe nanoparticle layer is deposited, the argon pressure in the magnetron sputtering instrument is maintained at 0.2 Pa. The Fe target is switched to a Pt target with a purity of ≥99.99% to ensure the purity of the loaded Pt single atoms. The sputtering time is set to 10 s to achieve a single-atom dispersion of Pt atoms on the surface of the Fe nanoparticle layer, preventing Pt atoms from agglomerating to form nanoparticles.

[0015] Preferably, in the step S3, the sample is taken out, placed in a quartz tube, and vacuum annealed in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C. The specific steps of obtaining the product of the present invention are:

[0016] (1) The sample with Fe nanoparticle layer and Pt single atom loaded on the substrate was placed in a quartz tube and placed in an annealing furnace. The annealing furnace was vacuumed to make the internal pressure ≤10 -3 Pa, to prevent the sample from being oxidized at high temperatures;

[0017] (2) The temperature was slowly raised to 350°C at a heating rate of 5 to 10°C / min to uniformly increase the temperature inside the sample and avoid stress inside the sample due to rapid temperature changes. The sample was kept at 350°C for 2 hours. The Pt atoms further diffused on the surface of the Fe nanoparticles and formed more stable interactions with the Fe atoms, promoting the anchoring of the Pt atoms on the Fe surface and optimizing the active site structure of the catalyst. After the holding period, the sample was allowed to cool to room temperature in the furnace to ensure the stability of the catalyst structure and obtain the corresponding catalyst.

[0018] A method for preparing a high-density Fe-based Pt single-atom alloy catalyst specifically comprises the following steps:

[0019] S1. Select nickel foam as the substrate and cut it into 1cm 2 The square was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, blown dry with nitrogen, and then placed in a magnetron sputtering instrument;

[0020] S2. The Fe target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 2 h, and the argon flow was set to 0.2 Pa. The Pt target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 10 s, and the argon flow was set to 0.2 Pa.

[0021] S3. Take out the sample, put it into a quartz tube, and perform vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 550° C. to obtain the product of the present invention.

[0022] Preferably, in the step S3, the sample is taken out, placed in a quartz tube, and vacuum annealed in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 550° C. The specific steps of obtaining the product of the present invention are:

[0023] (1) The sample with Fe nanoparticle layer and Pt single atom loaded on the substrate was placed in a quartz tube and placed in an annealing furnace. The annealing furnace was vacuumed to make the internal pressure ≤10 -3 Pa, to prevent the sample from being oxidized at high temperatures;

[0024] (2) The temperature was raised to 550°C at the same heating rate of 5-10°C / min and kept at this temperature for 2 hours to allow Fe and Pt atoms enough time to rearrange and interact at the atomic scale to form a more stable alloy phase that may have a different electronic structure. After the holding was completed, the sample was cooled to room temperature in the same furnace to ensure that the sample structure was stable and the corresponding catalyst was obtained.

[0025] A method for preparing a high-density Fe-based Pt single-atom alloy catalyst specifically comprises the following steps:

[0026] S1. Select an alumina template as the substrate and cut it into 1cm 2 The square was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, blown dry with nitrogen, and then placed in a magnetron sputtering instrument;

[0027] S2. The Fe target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 2 h, and the argon flow was set to 0.2 Pa. The Pt target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 10 s, and the argon flow was set to 0.2 Pa.

[0028] S3. Take out the sample, put it into a quartz tube, and perform vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C., thereby obtaining the product of the present invention.

[0029] Preferably, in the S1 step, an alumina template is selected as a substrate, cut into squares of size, ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, dried with nitrogen, and then placed in a magnetron sputtering instrument. The specific steps are as follows: selecting an alumina template as a substrate material, utilizing its high stability and excellent properties of a specific pore structure to ensure the stability of its own structure and the uniform distribution and anchoring of Fe nanoparticles and Pt single atoms during catalyst preparation and use, and then cleaning it according to the same process as nickel foam to remove impurities on the surface of the alumina template, providing a good foundation for subsequent metal deposition. After drying with nitrogen, the alumina template is placed in a magnetron sputtering instrument to prepare for metal deposition.

[0030] Preferably, in the step S3, the sample is taken out, placed in a quartz tube, and vacuum annealed in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C. The specific steps of obtaining the product of the present invention are:

[0031] (1) The sample loaded with Fe nanoparticle layer and Pt single atom in sequence on the alumina template substrate after step S1 is placed in a quartz tube and placed in an annealing furnace. The annealing furnace is vacuumed to make the internal pressure ≤10 -3 Pa, to prevent the sample from being oxidized at high temperatures;

[0032] (2) The temperature was slowly raised to 350°C at a heating rate of 5 to 10°C / min to uniformly increase the temperature inside the sample and avoid stress inside the sample due to rapid temperature changes. The sample was kept at 350°C for 2 hours. The Pt atoms further diffused on the surface of the Fe nanoparticles and formed more stable interactions with the Fe atoms, promoting the anchoring of the Pt atoms on the Fe surface and optimizing the active site structure of the catalyst. After the holding period, the sample was allowed to cool to room temperature in the furnace to ensure the stability of the catalyst structure and obtain the corresponding catalyst.

[0033] The present invention proposes a high-density Fe-based Pt single-atom alloy catalyst and a preparation method thereof, which has the following beneficial effects:

[0034] This catalyst and its preparation method achieves a Pt single-atom dispersion close to the theoretical maximum density (33%). Compared with traditional alloy catalysts, its Pt atom utilization rate is increased from less than 30% to close to the theoretical limit of 100%, significantly reducing the cost of precious metals. It breaks through the industry bottleneck of high loading and high stability of single-atom catalysts. In addition, Fe nanoparticles form a strong electronic coupling with Pt single atoms, and the catalytic active sites of Pt are regulated by Fe's d electrons, making the catalyst both highly active and selective in electrocatalytic, hydrogenation and other reactions.

[0035] This catalyst and its preparation method use a synergistic process of magnetron sputtering + vacuum annealing. Magnetron sputtering technology achieves the directional growth of Fe nanoparticles and atomic-level deposition of Pt single atoms by precisely controlling the sputtering time and gas pressure, avoiding agglomeration. Vacuum annealing promotes Fe-Pt interface alloying, retains surface defects at 350°C to anchor single atoms, and enhances interfacial bonding at 550°C, improving the long-term stability of the catalyst. In addition, the foamed nickel substrate uses a three-dimensional porous structure to provide abundant loading sites, and its conductivity accelerates charge transfer. The alumina template regulates the size uniformity of Fe nanoparticles through regular pores. Its chemical stability is extended to harsh reaction environments, expanding its adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is the XRD pattern of the Fe-based Pt single-atom alloy catalyst of the present invention;

[0037] Figure 2 This is a table of the Pt-Fe layered model data set obtained by density functional theory calculations of the present invention;

[0038] Figure 3 Graph showing the Gibbs free energy at different temperatures of the present invention. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is described in detail below through specific embodiments.

[0040] Example 1:

[0041] See also Figure 1-3 The present invention provides a high-density Fe-based Pt single-atom alloy catalyst, characterized in that it includes Fe nanoparticles and Pt single atoms loaded on the surface of the Fe nanoparticles, and the atomic fraction of the Pt single atoms is close to 33%, and the atomic fraction is the percentage of the number of surface Pt single atoms to the total number of surface iron and platinum atoms.

[0042] A method for preparing a high-density Fe-based Pt single-atom alloy catalyst specifically comprises the following steps:

[0043] S1. Select nickel foam as the substrate and cut it into 1cm 2 The square was cleaned with acetone, ethanol and deionized water for 10 minutes each, blown dry with nitrogen, and then placed in a magnetron sputtering instrument; nickel foam was selected as the substrate and cut into 1 cm 2 The squares were ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, dried with nitrogen, and then placed in a magnetron sputtering instrument. The specific steps are as follows: nickel foam was selected as the substrate material, and its high specific surface area and excellent conductivity were used to provide more attachment sites for the subsequently deposited Fe nanoparticles and Pt single atoms, which played a good supporting role in the catalytic reaction. The cut nickel foam blocks were placed in acetone, ethanol, and deionized water in turn, and ultrasonically cleaned for 10 minutes each. Acetone removed organic impurities such as oil on the surface of the nickel foam. Ethanol further cleaned the residual acetone and some water-soluble impurities. Deionized water thoroughly washed the residual cleaning agent and other tiny particles. After cleaning, the nickel foam was blown dry with nitrogen to remove residual moisture on the surface to prevent moisture from interfering with the subsequent magnetron sputtering process. The dried nickel foam was then placed in a magnetron sputtering instrument to prepare for metal deposition.

[0044] S2. The Fe target is placed in a magnetron sputtering instrument and evacuated for sputtering, the sputtering gas is argon, the sputtering time is 2 hours, and the argon flow is set to 0.2Pa. The Pt target is placed in a magnetron sputtering instrument and evacuated for sputtering, the sputtering gas is argon, the sputtering time is 10 seconds, and the argon flow is set to 0.2Pa. The Fe target is placed in a magnetron sputtering instrument and evacuated for sputtering, the sputtering gas is argon, the sputtering time is 2 hours, and the argon flow is set to 0.2Pa. The Pt target is placed in a magnetron sputtering instrument and evacuated for sputtering, the sputtering gas is argon, the sputtering time is 10 seconds, and the argon flow is set to 0.2Pa. The specific steps are as follows:

[0045] Deposition of Fe nanoparticle layer: Place Fe target with purity ≥99.95% in magnetron sputtering instrument, then evacuate the magnetron sputtering instrument to reduce the internal pressure of the magnetron sputtering instrument to the background vacuum degree ≤10 -4 Pa, and then introduce argon gas with a purity of ≥99.99% as sputtering gas, and adjust the gas pressure to 0.2 Pa. Argon ions are accelerated to collide with the Fe target surface under the action of the electric field, so that Fe atoms are sputtered from the target surface and deposited on the substrate surface. The sputtering time is set to 2 hours. During this time, Fe atoms continue to deposit on the substrate surface, gradually forming an Fe nanoparticle layer with a certain thickness and structure;

[0046] Loading of Pt single atoms: After completing the deposition of the Fe nanoparticle layer, maintain the argon pressure in the magnetron sputtering instrument at 0.2 Pa, switch the Fe target to a Pt target. The purity of the Pt target must be ≥99.99% to ensure the purity of the loaded Pt single atoms. Then, introduce argon with the same parameters as the sputtering gas, and set the sputtering time to 10s to achieve the dispersion of Pt atoms in the form of single atoms on the surface of the Fe nanoparticle layer to prevent Pt atoms from agglomerating to form nanoparticles.

[0047] S3. Take out the sample, place it in a quartz tube, and perform vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C. to obtain the product of the present invention. Take out the sample, place it in a quartz tube, and perform vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C. The specific steps of obtaining the product of the present invention are:

[0048] The sample with Fe nanoparticle layer and Pt single atom loaded on the substrate was placed in a quartz tube and placed in an annealing furnace. The annealing furnace was evacuated to a pressure of ≤10 -3 Pa, to prevent the sample from being oxidized at high temperatures;

[0049] The temperature was slowly raised to 350°C at a heating rate of 5-10°C / min to uniformly increase the temperature inside the sample to avoid stress inside the sample due to rapid temperature changes. The sample was kept at 350°C for 2 hours to allow the Pt single atoms to further diffuse on the surface of the Fe nanoparticles and form more stable interactions with the Fe atoms, thereby promoting the anchoring of the Pt single atoms on the Fe surface and optimizing the active site structure of the catalyst. After the holding period, the sample was allowed to cool to room temperature with the furnace to ensure the stability of the catalyst structure and obtain the corresponding catalyst.

[0050] In this embodiment, a nickel foam substrate with high specific surface area and conductivity was selected, ultrasonically cleaned with acetone, ethanol, and deionized water, and dried with nitrogen. The substrate was then placed in a magnetron sputtering apparatus. An Fe target with a purity of ≥99.95% was sputtered in 0.2 Pa argon for 2 hours to form an Fe nanoparticle layer. A Pt target with a purity of ≥99.99% was then switched to sputter for 10 seconds at the same pressure to achieve Pt single atom loading. Finally, the sample was placed in a quartz tube at a vacuum of ≤10 -3 Pa, heated to 350℃ at 5-10℃ / min and annealed for 2 hours under the conditions, and then cooled in the furnace to obtain a high-density Fe-based Pt single-atom alloy catalyst with a Pt single atom ratio of nearly 33%. This process achieves efficient dispersion of Pt single atoms and synergistic effect of Fe-Pt interface through substrate pretreatment, magnetron sputtering precision deposition and vacuum annealing optimization. Through the process route of "substrate property matching-magnetron sputtering precision deposition-low-temperature annealing interface activation", a high-density Fe-based Pt single-atom alloy structure is constructed on the nickel foam substrate to achieve efficient utilization of Pt single atoms, reaching an atomic utilization rate of ≈100%, and optimizing catalytic performance. The core innovation lies in balancing single-atom dispersion, interface stability and catalytic activity through parameter control.

[0051] Example 2:

[0052] See also Figure 1-3 The present invention provides a high-density Fe-based Pt single-atom alloy catalyst, characterized in that it includes Fe nanoparticles and Pt single atoms loaded on the surface of the Fe nanoparticles, and the atomic fraction of the Pt single atoms is close to 33%, and the atomic fraction is the percentage of the number of surface Pt single atoms to the total number of surface iron and platinum atoms.

[0053] A method for preparing a high-density Fe-based Pt single-atom alloy catalyst specifically comprises the following steps:

[0054] S1. Select nickel foam as the substrate and cut it into 1cm 2 The square was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, blown dry with nitrogen, and then placed in a magnetron sputtering instrument.

[0055] S2. Place the Fe target in a magnetron sputtering instrument and evacuate the vacuum for sputtering. The sputtering gas is argon, the sputtering time is 2 hours, and the argon flow is set to 0.2Pa. Place the Pt target in a magnetron sputtering instrument and evacuate the vacuum for sputtering. The sputtering gas is argon, the sputtering time is 10 seconds, and the argon flow is set to 0.2Pa.

[0056] S3. Take out the sample, place it in a quartz tube, and perform vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 550° C. to obtain the product of the present invention; take out the sample, place it in a quartz tube, and perform vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 550° C. The specific steps of obtaining the product of the present invention are:

[0057] The sample with Fe nanoparticle layer and Pt single atom loaded on the substrate was placed in a quartz tube and placed in an annealing furnace. The annealing furnace was evacuated to a pressure of ≤10 -3 Pa, to prevent the sample from being oxidized at high temperatures;

[0058] The temperature was raised to 550°C at the same heating rate of 5-10°C / min and kept at this temperature for 2 hours to allow Fe and Pt atoms enough time to rearrange and interact at the atomic scale to form a more stable alloy phase that may have a different electronic structure. After the holding is completed, it was also cooled to room temperature in the furnace to ensure the stability of the sample structure and obtain the corresponding catalyst.

[0059] In this embodiment, a nickel foam substrate was cut into squares, ultrasonically cleaned with acetone, ethanol, and deionized water, and dried with nitrogen. The substrate was then placed in a magnetron sputtering apparatus, and an Fe target with a purity of ≥99.95% was sputtered in 0.2 Pa argon for 2 hours to form an Fe nanoparticle layer. A Pt target with a purity of ≥99.99% was then switched to sputter for 10 seconds at the same pressure to achieve Pt single atom loading. The sample was then placed in a quartz tube and placed in a vacuum of ≤10 -4 Pa, heating to 550℃ at 5-10℃ / min for 2 hours and cooling in the furnace to produce a high-density Fe-based Pt single-atom alloy catalyst with a Pt single-atom ratio of nearly 33%. This process promotes deep alloying of Fe and Pt atoms, enhances interfacial bonding, and optimizes electronic coupling effects by increasing the annealing temperature to 550℃, making it suitable for scenarios requiring higher stability or high-temperature catalysis, while retaining the single-atom dispersion advantage of precise deposition by magnetron sputtering.

[0060] Example 3:

[0061] See also Figure 1-3The present invention provides a high-density Fe-based Pt single-atom alloy catalyst, characterized in that it includes Fe nanoparticles and Pt single atoms loaded on the surface of the Fe nanoparticles, and the atomic fraction of the Pt single atoms is close to 33%, and the atomic fraction is the percentage of the number of surface Pt single atoms to the total number of surface iron and platinum atoms.

[0062] A method for preparing a high-density Fe-based Pt single-atom alloy catalyst specifically comprises the following steps:

[0063] S1. Select an alumina template as the substrate and cut it into 1cm 2 The square was cleaned with acetone, ethanol and deionized water for 10 minutes each, blown dry with nitrogen, and then placed in a magnetron sputtering instrument; an alumina template was selected as the substrate and cut into 1 cm 2 The square was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, dried with nitrogen, and then placed in a magnetron sputtering instrument. The specific steps are as follows: an alumina template was selected as the substrate material, and its high stability and excellent characteristics of a specific pore structure were utilized to ensure the stability of its own structure and the uniform distribution and anchoring of Fe nanoparticles and Pt single atoms during the preparation and use of the catalyst. Then, it was cleaned according to the same process as the nickel foam to remove impurities on the surface of the alumina template, providing a good foundation for subsequent metal deposition. After drying with nitrogen, the alumina template was placed in a magnetron sputtering instrument and prepared for metal deposition.

[0064] S2. Place the Fe target in a magnetron sputtering instrument and evacuate the vacuum for sputtering. The sputtering gas is argon, the sputtering time is 2 hours, and the argon flow is set to 0.2Pa. Place the Pt target in a magnetron sputtering instrument and evacuate the vacuum for sputtering. The sputtering gas is argon, the sputtering time is 10 seconds, and the argon flow is set to 0.2Pa.

[0065] S3. Taking out the sample, placing it in a quartz tube, and performing vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C. to obtain the product of the present invention; Taking out the sample, placing it in a quartz tube, and performing vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C. The specific steps of obtaining the product of the present invention are:

[0066] The sample loaded with Fe nanoparticle layer and Pt single atom on the alumina template substrate in step S1 was placed in a quartz tube and placed in an annealing furnace. The annealing furnace was evacuated to a pressure of ≤10 -3 Pa, to prevent the sample from being oxidized at high temperatures;

[0067] The temperature was slowly raised to 350°C at a heating rate of 5-10°C / min to uniformly increase the temperature inside the sample to avoid stress inside the sample due to rapid temperature changes. The sample was kept at 350°C for 2 hours to allow the Pt single atoms to further diffuse on the surface of the Fe nanoparticles and form more stable interactions with the Fe atoms, thereby promoting the anchoring of the Pt single atoms on the Fe surface and optimizing the active site structure of the catalyst. After the holding period, the sample was allowed to cool to room temperature with the furnace to ensure the stability of the catalyst structure and obtain the corresponding catalyst.

[0068] In this embodiment, an alumina template with high chemical stability and regular pore structure was selected as the substrate. After ultrasonic cleaning with acetone, ethanol, and deionized water and drying with nitrogen, it was placed in a magnetron sputtering instrument. An Fe target with a purity of ≥99.95% was sputtered in 0.2 Pa argon for 2 hours to form an Fe nanoparticle layer. Then, a Pt target with a purity of ≥99.99% was switched to sputter for 10 seconds at the same pressure to achieve Pt single atom loading. Subsequently, the sample was placed in a quartz tube and placed in a vacuum of ≤10 -4 Under the conditions of Pa, the catalyst was heated to 350°C at a rate of 5-10°C / min and annealed for 2 hours, followed by furnace cooling, to produce a high-density Fe-based Pt single-atom alloy catalyst with a Pt single-atom ratio of nearly 33%. This process utilizes the structural guidance of the alumina template to control the growth orientation and size distribution of Fe nanoparticles. Combined with low-temperature annealing to prevent interfacial reactions between alumina and Fe / Pt, this process ensures high dispersion of Pt single atoms while leveraging the insulating properties and chemical stability of alumina to optimize the electronic structure of the catalytic active sites. This makes it suitable for catalytic systems operating in corrosive environments or with special requirements for substrate stability.

[0069] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A high-density Fe-based Pt single-atom alloy catalyst, characterized by: The invention comprises Fe nanoparticles and Pt single atoms loaded on the surface of the Fe nanoparticles, wherein the atomic ratio of the Pt single atoms is close to 33%, and the atomic ratio is the percentage of the number of surface Pt single atoms to the total number of surface iron and platinum atoms.

2. The method for preparing a high-density Fe-based Pt single-atom alloy catalyst according to claim 1, comprising the following steps: S1. Select nickel foam as the substrate and cut it into 1cm 2 The square was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, blown dry with nitrogen, and then placed in a magnetron sputtering instrument; S2. The Fe target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 2 h, and the argon flow was set to 0.2 Pa. The Pt target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 10 s, and the argon flow was set to 0.2 Pa. S3. Take out the sample, put it into a quartz tube, and perform vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C. to obtain the product of the present invention.

3. The high-density Fe-based Pt single-atom alloy catalyst according to claim 2, characterized in that: In the step S1, nickel foam is selected as the substrate and cut into pieces of 1 cm in size. 2 The squares were ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, blown dry with nitrogen, and then placed in a magnetron sputtering instrument. The specific steps are as follows: nickel foam was selected as the substrate material, and its high specific surface area and excellent conductivity provided more attachment sites for the subsequently deposited Fe nanoparticles and Pt single atoms, playing a good supporting role in the catalytic reaction. The cut nickel foam blocks were placed in acetone, ethanol, and deionized water, and ultrasonically cleaned for 10 minutes each. Acetone removed organic impurities such as oil on the surface of the nickel foam. Ethanol further cleaned the remaining acetone and some water-soluble impurities. Deionized water thoroughly washed away the remaining cleaning agent and other tiny particles. After cleaning, the nickel foam was blown dry with nitrogen to remove residual moisture on the surface to prevent moisture from interfering with the subsequent magnetron sputtering process. The dried nickel foam was then placed in the magnetron sputtering instrument to prepare for metal deposition.

4. The high-density Fe-based Pt single-atom alloy catalyst according to claim 2, characterized in that: In the S2 step, the Fe target is placed in a magnetron sputtering apparatus and evacuated for sputtering, the sputtering gas is argon, the sputtering time is 2 h, and the argon flow is set to 0.2 Pa. The Pt target is placed in a magnetron sputtering apparatus and evacuated for sputtering, the sputtering gas is argon, the sputtering time is 10 s, and the argon flow is set to 0.2 Pa. The specific steps are as follows: (1) Deposition of Fe nanoparticle layer: Place Fe target with purity ≥99.95% in magnetron sputtering instrument, and then evacuate the magnetron sputtering instrument to reduce the internal pressure of the magnetron sputtering instrument to the background vacuum degree ≤10 -4 Pa, then introduce argon gas with a purity of ≥99.99% as the sputtering gas. The pressure is adjusted to 0.2 Pa and the sputtering power is turned on. Under the action of the electric field, the argon ions are accelerated to collide with the Fe target surface, causing Fe atoms to sputter from the target surface and deposit on the substrate surface. The sputtering time is set to 2 hours. During this time, Fe atoms continue to deposit on the substrate surface, gradually forming an Fe nanoparticle layer with a certain thickness and structure. (2) Loading of Pt Single Atoms: After the Fe nanoparticle layer is deposited, the argon pressure in the magnetron sputtering instrument is maintained at 0.2 Pa. The Fe target is switched to a Pt target with a purity of ≥99.99% to ensure the purity of the loaded Pt single atoms. The sputtering time is set to 10 s to achieve a single-atom dispersion of Pt atoms on the surface of the Fe nanoparticle layer, preventing Pt atoms from agglomerating to form nanoparticles.

5. The high-density Fe-based Pt single-atom alloy catalyst according to claim 2, characterized in that: In the step S3, the sample is taken out, placed in a quartz tube, and vacuum annealed in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C. The specific steps of obtaining the product of the present invention are: (1) The sample with Fe nanoparticle layer and Pt single atom loaded on the substrate was placed in a quartz tube and placed in an annealing furnace. The annealing furnace was vacuumed to make the internal pressure ≤10 -3 Pa, to prevent the sample from being oxidized at high temperatures; (2) The temperature was slowly raised to 350°C at a heating rate of 5 to 10°C / min to uniformly increase the temperature inside the sample and avoid stress inside the sample due to rapid temperature changes. The sample was kept at 350°C for 2 hours. The Pt atoms further diffused on the surface of the Fe nanoparticles and formed more stable interactions with the Fe atoms, promoting the anchoring of the Pt atoms on the Fe surface and optimizing the active site structure of the catalyst. After the holding period, the sample was allowed to cool to room temperature in the furnace to ensure the stability of the catalyst structure and obtain the corresponding catalyst.

6. The method for preparing a high-density Fe-based Pt single-atom alloy catalyst according to claim 1, comprising the following steps: S1. Select nickel foam as the substrate and cut it into 1cm 2 The square was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, blown dry with nitrogen, and then placed in a magnetron sputtering instrument; S2. The Fe target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 2 h, and the argon flow was set to 0.2 Pa. The Pt target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 10 s, and the argon flow was set to 0.2 Pa. S3. Take out the sample, put it into a quartz tube, and perform vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 550° C. to obtain the product of the present invention.

7. The high-density Fe-based Pt single-atom alloy catalyst according to claim 6, characterized in that: In the step S3, the sample is taken out, placed in a quartz tube, and vacuum annealed in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 550° C. The specific steps of obtaining the product of the present invention are: (1) The sample with Fe nanoparticle layer and Pt single atom loaded on the substrate was placed in a quartz tube and placed in an annealing furnace. The annealing furnace was vacuumed to make the internal pressure ≤10 -3 Pa, to prevent the sample from being oxidized at high temperatures; (2) The temperature was raised to 550°C at the same heating rate of 5-10°C / min and kept at this temperature for 2 hours to allow Fe and Pt atoms enough time to rearrange and interact at the atomic scale to form a more stable alloy phase that may have a different electronic structure. After the holding was completed, the sample was cooled to room temperature in the same furnace to ensure that the sample structure was stable and the corresponding catalyst was obtained.

8. The method for preparing a high-density Fe-based Pt single-atom alloy catalyst according to claim 1, characterized in that: The specific steps include: S1. Select an alumina template as the substrate and cut it into 1cm 2 The square was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, blown dry with nitrogen, and then placed in a magnetron sputtering instrument; S2. The Fe target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 2 h, and the argon flow was set to 0.2 Pa. The Pt target was placed in a magnetron sputtering apparatus and vacuumed for sputtering. The sputtering gas was argon, the sputtering time was 10 s, and the argon flow was set to 0.2 Pa. S3. Take out the sample, put it into a quartz tube, and perform vacuum annealing in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C., thereby obtaining the product of the present invention.

9. The high-density Fe-based Pt single-atom alloy catalyst according to claim 8, characterized in that: In the step S1, an alumina template is selected as the substrate and cut into pieces of 1 cm in size. 2 The square was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes each, dried with nitrogen, and then placed in a magnetron sputtering instrument. The specific steps are as follows: an alumina template was selected as the substrate material, and its high stability and excellent characteristics of a specific pore structure were utilized to ensure the stability of its own structure and the uniform distribution and anchoring of Fe nanoparticles and Pt single atoms during the preparation and use of the catalyst. Then, it was cleaned according to the same process as the nickel foam to remove impurities on the surface of the alumina template, providing a good foundation for subsequent metal deposition. After drying with nitrogen, the alumina template was placed in a magnetron sputtering instrument and prepared for metal deposition.

10. The high-density Fe-based Pt single-atom alloy catalyst according to claim 8, characterized in that: In the step S3, the sample is taken out, placed in a quartz tube, and vacuum annealed in an annealing furnace. The vacuum annealing time is 2 hours, and the vacuum annealing temperature is set to 350° C. The specific steps of obtaining the product of the present invention are: (1) The sample loaded with Fe nanoparticle layer and Pt single atom in sequence on the alumina template substrate after step S1 was placed in a quartz tube and placed in an annealing furnace. The annealing furnace was vacuumed to make the internal pressure ≤10 -3 Pa, to prevent the sample from being oxidized at high temperatures; (2) The temperature was slowly raised to 350°C at a heating rate of 5 to 10°C / min to uniformly increase the temperature inside the sample and avoid stress inside the sample due to rapid temperature changes. The sample was kept at 350°C for 2 hours. The Pt atoms further diffused on the surface of the Fe nanoparticles and formed more stable interactions with the Fe atoms, promoting the anchoring of the Pt atoms on the Fe surface and optimizing the active site structure of the catalyst. After the holding period, the sample was allowed to cool to room temperature in the furnace to ensure the stability of the catalyst structure and obtain the corresponding catalyst.

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