A two-dimensional nickel-based sulfide supported Pt monatomic catalyst and a preparation method thereof

Abstract

This invention discloses a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst. The catalyst includes a support and an active center; the support is a nickel-based sulfide; the active center is Pt; the Pt metal atoms are uniformly dispersed and supported on the nickel-based sulfide; the Pt metal atoms exist in the form of single atoms. The nickel-based sulfide is NiS2-HS or NiS2-DS. This invention also discloses a method for preparing the above catalyst, which involves direct calcination and hydrothermal / calcination, followed by Pt deposition to obtain corresponding nickel-based sulfide-supported Pt single-atom catalysts, and confirms the potential of two-dimensional nickel-based sulfide single atoms in alkaline water electrolysis for hydrogen production.

Description

Technical Field

[0001] This invention belongs to the field of nanocatalyst synthesis technology, and in particular relates to a two-dimensional nickel-based sulfide supported Pt single-atom catalyst and its preparation method. Background Technology

[0002] Traditional fossil fuels, as a major driving force for global economic development, hold an irreplaceable position in the energy sector. Hydrogen energy, as a clean, high-energy, and pollution-free "green energy," is considered one of the ideal energy sources for addressing the energy and environmental crises in the post-oil era. Electrolysis of water for hydrogen evolution has gradually become a research hotspot due to its high efficiency, ease of control, and pollution-free operation. However, most nickel-based sulfides currently exhibit sulfur species loss and instability due to high voltage and prolonged operation.

[0003] Currently, non-precious metals are highly favored due to their economic benefits and synergistic effects; however, the preparation cost of benchmark catalysts made from precious metals such as Pt is expensive. At present, Pt single atoms have become a hot topic in the field of water electrolysis due to their extensive active surface area and high atom utilization rate. Calcined two-dimensional self-supporting nickel-based sulfides are favored compared to one-dimensional structures due to their highly stable network structure and acceptor active area. Furthermore, this two-dimensional nickel-based sulfide nanosheet structure possesses efficient electron transfer capabilities and porous channels that accelerate gas release, thereby accelerating kinetics.

[0004] Therefore, the key to achieving large-scale production of hydrogen evolution by electrolysis of precious metals lies in further developing novel, inexpensive, efficient, and stable catalysts for atomically dispersed precious metals. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a two-dimensional nickel-based sulfide supported Pt single-atom catalyst.

[0006] The second technical problem to be solved by the present invention is to provide a method for preparing a two-dimensional nickel-based sulfide supported Pt single-atom catalyst; the preparation method obtains corresponding different nickel-based sulfide supported Pt single-atom catalysts by direct calcination and hydrothermal / calcination, followed by Pt deposition, and confirms the potential ability of two-dimensional nickel-based sulfide single atoms in alkaline water electrolysis for hydrogen production.

[0007] To solve the first technical problem mentioned above, the present invention adopts the following technical solution:

[0008] A two-dimensional nickel-based sulfide supported Pt single-atom catalyst, comprising a support and an active center;

[0009] The carrier is a nickel-based sulfide;

[0010] The active center is Pt;

[0011] The Pt metal atoms are uniformly dispersed and loaded on the nickel-based sulfide;

[0012] The Pt metal atoms exist in the form of single atoms.

[0013] To solve the second technical problem mentioned above, the first technical solution adopted by the present invention is as follows:

[0014] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0015] 1) Using nickel salt as a precursor, add organic medium and reducing agent, mix thoroughly to obtain mixture A;

[0016] 2) Place the mixture A and the substrate material in a polytetrafluoroethylene-lined reactor for hydrothermal reaction;

[0017] 3) After the hydrothermal reaction cools down, the LDH self-supporting material is obtained. It is then dried in a vacuum drying oven at 30-60℃ for 12-24 hours to obtain substrate material A.

[0018] 4) The obtained substrate material A is calcined in air at 200-400℃ for 2-4 hours to obtain substrate material B;

[0019] 5) The obtained substrate material B and solid sulfur were calcined together under an inert gas atmosphere at 200-400℃ for 2-4 hours to obtain substrate material C;

[0020] 6) The obtained substrate material C was electrochemically deposited under alkaline conditions and then vacuum dried at 30-60℃ for 12-24 h to obtain a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst (named Pt in this application). SA NiS2-HS).

[0021] Preferably, in step 1), the nickel salt is 50-100 mg of nickel nitrate hexahydrate, the organic medium is 10-15 mL of anhydrous methanol with a mass fraction of 99.9%, and the reducing agent is 0.5-1.0 mL of N,N dimethylformamide.

[0022] Preferably, in step 2), the substrate material is nickel foam (NF), the hydrothermal reaction temperature is 120-180℃, and the hydrothermal reaction time is 500-600 min.

[0023] Preferably, in step 5), the calcination temperature is 250-350℃ and the heating rate is 2-4℃ / min.

[0024] Preferably, in step 5), the solid sulfur is sublimed sulfur with a mass of 0.3-1.0g.

[0025] Preferably, in step 5), the inert gas is nitrogen or argon.

[0026] Preferably, in step 6), the alkaline environment is 50-100 mg potassium chloroplatinate dispersed in 50-100 mL of 1 M KOH electrolyte solution; the working electrode is a nickel-based sulfide support directly grown on nickel foam, the counter electrode is a carbon rod, and the reference electrode is Hg / HgO.

[0027] Preferably, in step 6), the electrochemical deposition is performed using a galvanochronous method, the applied reversible hydrogen voltage range is [-0.576V, -0.426V], and the duration is set to 300-1000s.

[0028] To solve the second technical problem mentioned above, the second technical solution adopted by the present invention is as follows:

[0029] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0030] 1) Calcine the base material D with solid sulfur at 200-400℃ in an inert gas atmosphere for 2-4 hours to obtain base material E;

[0031] 2) The obtained substrate material E was electrochemically deposited under alkaline conditions and then vacuum dried at 30-60℃ for 12-24 h to obtain a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst (named Pt in this application). SA NiS2-DS).

[0032] Preferably, in step 1), the substrate material D is nickel foam.

[0033] Preferably, in step 1), the solid sulfur is sublimed sulfur with a mass of 0.3-1.0g.

[0034] Preferably, in step 2), the alkaline environment is 50-100 mg potassium chloroplatinate dispersed in 50-100 mL of 1 M KOH electrolyte solution; the working electrode is a nickel-based sulfide support directly grown on nickel foam, the counter electrode is a carbon rod, and the reference electrode is Hg / HgO.

[0035] Preferably, in step 2), the electrochemical deposition is performed using a galvanochronous method, the applied reversible hydrogen voltage range is [-0.576V, -0.426V], and the duration is set to 300-1000s.

[0036] Any range described in this invention includes the endpoint, any value between the endpoints, and any subrange consisting of the endpoint or any value between the endpoints.

[0037] Unless otherwise specified, all raw materials used in this invention can be obtained commercially, and the equipment used in this invention can be conventional equipment in the relevant field or refer to existing technology in the relevant field.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] This invention utilizes direct calcination and hydrothermal / calcination followed by Pt deposition to obtain Pt single-atom catalysts supported on different nickel-based sulfides, demonstrating the potential of two-dimensional nickel-based sulfide single atoms in alkaline water electrolysis for hydrogen production. The substrate material was optimized by varying the calcination time, calcination temperature, and the amount of solid sulfur used; and the Pt single-atom loading was precisely controlled by adjusting the deposition voltage and time. TEM analysis showed no obvious particulate structure in the two-dimensional catalyst, confirming uniform Pt atom dispersion. Further XRD phase characterization revealed no Pt particle diffraction peaks, indicating the presence of Pt single atoms. XPS analysis confirmed that Pt atoms existed in different oxidation states, without any metallic valence state, fully demonstrating Pt single-atom loading on the two-dimensional nickel-based sulfide substrate. Finally, LSV polarization curves and Tafel slope performance characteristics demonstrated the potential hydrogen evolution capability of the obtained material in alkaline media. Attached Figure Description

[0040] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0041] Figure 1 These are TEM images of two-dimensional nickel-based sulfides before and after electrodeposition, corresponding to Example 1 of the present invention;

[0042] Figure 2 The XRD patterns of the two-dimensional nickel-based sulfide before and after electrodeposition are shown in Example 1 of this invention.

[0043] Figure 3 These are the XPS full spectra of two-dimensional nickel-based sulfide electrodeposition before and after the deposition of the corresponding two-dimensional nickel-based sulfide in Example 1 of the present invention;

[0044] Figure 4 This is the fine XPS spectrum of Pt element corresponding to the two-dimensional nickel-based sulfide in Example 1 of the present invention;

[0045] Figure 5 This is the fine XPS spectrum of Ni element corresponding to the two-dimensional nickel-based sulfide in Example 1 of the present invention;

[0046] Figure 6 The fine XPS spectrum of the S element corresponding to the two-dimensional nickel-based sulfide in Example 1 of this invention;

[0047] Figure 7This is the fine XPS spectrum of the O element corresponding to the two-dimensional nickel-based sulfide in Example 1 of the present invention;

[0048] Figure 8 This is a performance curve diagram of the two-dimensional nickel-based sulfide corresponding to Example 1 of the present invention. Detailed Implementation

[0049] To more clearly illustrate the present invention, the following description, in conjunction with embodiments, provides further insight. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0050] As one aspect of the present invention, a two-dimensional nickel-based sulfide supported Pt single-atom catalyst is provided, comprising a support and an active center;

[0051] The carrier is a nickel-based sulfide;

[0052] The active center is Pt;

[0053] The Pt metal atoms are uniformly dispersed and loaded on the nickel-based sulfide;

[0054] The Pt metal atoms exist in the form of single atoms.

[0055] Preferably, the nickel-based sulfide is NiS2-HS or NiS2-DS.

[0056] As another aspect of the present invention, the preparation method of the above-mentioned two-dimensional nickel-based sulfide supported Pt single-atom catalyst of the present invention includes the following steps:

[0057] 1) Using nickel salt as a precursor, add organic medium and reducing agent, mix thoroughly to obtain mixture A;

[0058] 2) Place the mixture A and the substrate material in a polytetrafluoroethylene-lined reactor for hydrothermal reaction;

[0059] 3) After the hydrothermal reaction cools down, the LDH self-supporting material is obtained. It is then dried in a vacuum drying oven at 30-60℃ for 12-24 hours to obtain substrate material A.

[0060] 4) The obtained substrate material A is calcined in air at 200-400℃ for 2-4 hours to obtain substrate material B;

[0061] 5) The obtained substrate material B and solid sulfur were calcined together under an inert gas atmosphere at 200-400℃ for 2-4 hours to obtain substrate material C;

[0062] 6) The obtained substrate material C was electrochemically deposited under alkaline conditions and then vacuum dried at 30-60℃ for 12-24 h to obtain a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst Pt. SA NiS2-HS.

[0063] According to certain embodiments of the present invention, in step 1), the nickel salt is 50-100 mg of nickel nitrate hexahydrate, the organic medium is 10-15 mL of anhydrous methanol with a mass fraction of 99.9%, and the reducing agent is 0.5-1.0 mL of N,N dimethylformamide.

[0064] According to certain embodiments of the present invention, in step 2), the substrate material is nickel foam (abbreviated as: NF), the hydrothermal reaction temperature is 120-180℃, and the hydrothermal reaction time is 500-600min.

[0065] According to certain embodiments of the present invention, in step 5), the calcination temperature is 250-350°C and the heating rate is 2-4°C / min.

[0066] According to certain embodiments of the present invention, in step 5), the solid sulfur is sublimed sulfur with a mass of 0.3-1.0 g.

[0067] According to some embodiments of the present invention, in step 5), the inert gas is nitrogen or argon.

[0068] According to certain embodiments of the present invention, in step 6), the alkaline environment is 50-100 mg potassium chloroplatinate dispersed in 50-100 mL of 1 M KOH electrolyte solution; the working electrode is a nickel-based sulfide support directly grown on nickel foam, the counter electrode is a carbon rod, and the reference electrode is Hg / HgO.

[0069] According to certain embodiments of the present invention, in step 6), the electrochemical deposition is performed using a galvanochronous method, the applied reversible hydrogen voltage range is [-0.576V, -0.426V], and the duration is set to 300-1000s.

[0070] As another aspect of the present invention, the preparation method of the above-mentioned two-dimensional nickel-based sulfide supported Pt single-atom catalyst of the present invention includes the following steps:

[0071] 1) Calcine the base material D with solid sulfur at 200-400℃ in an inert gas atmosphere for 2-4 hours to obtain base material E;

[0072] 2) The obtained substrate material E was electrochemically deposited under alkaline conditions and then vacuum dried at 30-60℃ for 12-24 h to obtain a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst Pt. SA NiS2-DS.

[0073] According to certain embodiments of the present invention, in step 1), the substrate material D is nickel foam.

[0074] According to certain embodiments of the present invention, in step 1), the solid sulfur is sublimed sulfur with a mass of 0.3-1.0 g.

[0075] According to certain embodiments of the present invention, in step 2), the alkaline environment is 50-100 mg potassium chloroplatinate dispersed in 50-100 mL of 1 M KOH electrolyte solution; the working electrode is a nickel-based sulfide support directly grown on nickel foam, the counter electrode is a carbon rod, and the reference electrode is Hg / HgO.

[0076] According to certain embodiments of the present invention, in step 2), the electrochemical deposition is performed using a galvanochronous method, the applied reversible hydrogen voltage range is [-0.576V, -0.426V], and the duration is set to 300-1000s.

[0077] In this application, the hydrogen evolution performance test of the catalyst for water electrolysis to produce hydrogen includes the following main steps:

[0078] Cut the catalyst product into 1*2cm pieces. 2 The hydrogen evolution performance of the sized flakes was tested in 1M KOH alkaline electrolyte.

[0079] Example 1

[0080] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0081] (1) Accurately weigh 100 mg Ni(NO3)2·6H2O into a clean beaker, measure 12 mL of methanol and 0.85 mL of N,N-dimethylformamide and transfer them to the beaker. After sonication, transfer them to the lining of a 25 mL hydrothermal reactor and place a 2*2.5 cm NF sheet in the hydrothermal reactor. Keep it at 151.5 °C for 550 min. After the reaction is complete, remove the sheet with tweezers and rinse it with deionized water and ethanol. Then, vacuum dry it at 40 °C to obtain Ni(OH)2.

[0082] (2) Place one piece of Ni(OH)2 precursor in a magnetic boat, place the magnetic boat in a tube furnace and heat it to 300°C at a rate of 3°C / min, and keep it in the air for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black NiO.

[0083] (3) Place 1.0g of sublimed sulfur S powder and the prepared NiO in the upper and lower reaches of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-HS.

[0084] (4) Place 0.3g of sublimed sulfur S powder and NF in the upper and lower reaches of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-DS.

[0085] (5) Accurately weigh 75 mg of potassium chloroplatinate and dissolve it in 50 mL of 1 M KOH. Using a mercuric oxide electrode as the reference electrode, set the deposition voltage to -1.43 V and the deposition time to 500 s. Dry the resulting sample in a vacuum drying oven at 40 °C for 24 h. The resulting product is a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst, denoted as Pt. SA NiS2-HS and Pt SA NiS2-DS.

[0086] The Pt single-atom catalyst is used for the alkaline hydrogen evolution reaction: a 1*2cm piece of the obtained catalyst is cut off. 2 The flakes are subjected to an electrolysis reaction to produce hydrogen in an alkaline environment of 1 M KOH.

[0087] Figure 1 The images show SEM (Scanning Electron Microscopy) images of the nickel-based sulfides obtained in this embodiment. The images show that the directly calcined sample exhibits a two-dimensional raised framework, and no obvious aggregation was observed after deposition. The hydrothermal-calcined sample exhibits a two-dimensional layered structure, and no obvious aggregation was observed after deposition. The obtained two-dimensional structures all indicate that Pt atoms are deposited relatively dispersedly on the support.

[0088] Figure 2 The XRD pattern of the nickel-based sulfide obtained in this embodiment shows that three relatively obvious diffraction peaks are from nickel foam, and the remaining diffraction peaks are all NiS2 crystal phase peaks. This indicates that the two-dimensional substrate material exists in the nickel disulfide crystal phase, and no crystal phase diffraction peaks of Pt particles were found after deposition, which is consistent with the conclusion of relatively dispersed Pt obtained from SEM analysis.

[0089] Figure 3 This is the total XPS energy spectrum of the two-dimensional nickel-based sulfide obtained in this example, indicating the presence of elements such as Pt, Ni, S, and O in the obtained nickel-based sulfide Pt single-atom catalyst. Figure 4The XPS energy dispersive spectra of Pt in two single-atom Pt catalysts clearly show that Pt exists in different oxidation states in the corresponding nickel-based sulfides, and Pt is not present in the catalysts. 0 The metal orbital peaks indicate that Pt particles or clusters do not exist. Figure 5 The fine XPS energy spectrum of the obtained nickel-based sulfide Ni element clearly shows that NiS2-HS after deposition... 2+ with Ni 3+ The transition to an intermediate valence state between Pt and Ni indicates a strong interaction between them; while the appearance of Ni in NiS2-DS... 0 The metallic orbital peaks should be attributed to the NF substrate. Figure 6 The fine XPS spectra of sulfur in the obtained nickel-based sulfides show that S2 was detected in all of them. 2- The presence of this indicates that the obtained two-dimensional nickel-based sulfides all exist in the form of disulfides, which is consistent with the disulfide conclusions of XRD.

[0090] Figure 5 This fully demonstrates that Pt exists as single atoms in different oxidation states within two-dimensional nickel-based sulfides, indicating the promising future of electrodeposition for preparing single-atom catalysts. Figure 1 and Figure 2 The deposition did not change the two-dimensional structure of the nickel-based sulfide, demonstrating the stable characteristics of the two-dimensional structure obtained by calcination.

[0091] Figure 7 The fine XPS energy spectrum of the O element in the obtained nickel-based sulfide shows the presence of MO bonds.

[0092] Figure 8 The graph shows the hydrogen evolution performance of the obtained nickel-based sulfide under alkaline conditions of 1M KOH, Pt SA NiS2-DS and Pt SA NiS2-HS catalyst at 10 mAcm -2 The corresponding overpotentials were 44 mV and 53 mV, respectively, which were much higher than those of the undeposited samples, indicating the excellent performance of the Pt single-atom catalyst.

[0093] Example 2

[0094] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0095] (1) Accurately weigh 100 mg Ni(NO3)2·6H2O into a clean beaker, measure 12 mL of methanol and 0.85 mL of N,N-dimethylformamide and transfer them to the beaker. After sonication, transfer them to the lining of a 25 mL hydrothermal reactor. Place a 2*2.5 cm clean nickel foam NF sheet in the hydrothermal reactor and keep it at 151.5 °C for 550 min. After the reaction is complete, remove the sheet with tweezers and rinse it with deionized water and ethanol. Then, vacuum dry it at 40 °C to obtain Ni(OH)2.

[0096] (2) Place one piece of Ni(OH)2 precursor in a magnetic boat, place the magnetic boat in a tube furnace and heat it to 300°C at a rate of 3°C / min, and keep it in the air for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black NiO.

[0097] (3) Place 1g of sublimed sulfur S powder and the prepared NiO in the upstream and downstream of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-HS.

[0098] (4) Place 0.3g of sublimed sulfur S powder and clean foamed nickel NF in the upper and lower reaches of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-DS.

[0099] (5) Accurately weigh 75 mg of potassium chloroplatinate and dissolve it in 50 mL of 1 M KOH. Using a mercuric oxide electrode as the reference electrode, set the deposition voltage to -1.4 V and the deposition time to 500 s. Dry the resulting sample in a vacuum drying oven at 40 °C for 24 h. The resulting product is the two-dimensional nickel-based sulfide-supported Pt single-atom catalyst, denoted as Pt. SA NiS2-HS and Pt SA NiS2-DS.

[0100] Example 3

[0101] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0102] (1) Accurately weigh 100 mg Ni(NO3)2·6H2O into a clean beaker, measure 12 mL of methanol and 0.85 mL of N,N-dimethylformamide and transfer them to the beaker. After sonication, transfer them to the lining of a 25 mL hydrothermal reactor. Place a 2*2.5 cm clean nickel foam NF in the hydrothermal reactor and keep it at 151.5 °C for 550 min. After the reaction is complete, remove the flakes with tweezers and rinse them with deionized water and ethanol. Then, vacuum dry them at 40 °C to obtain Ni(OH)2.

[0103] (2) Place one piece of Ni(OH)2 precursor in a magnetic boat, place the magnetic boat in a tube furnace and heat it to 300°C at a rate of 3°C / min, and keep it in the air for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black NiO.

[0104] (3) Place 1g of sublimed sulfur S powder and the prepared NiO in the upstream and downstream of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-HS.

[0105] (4) Place 0.3g of sublimed sulfur S powder and NF in the upper and lower reaches of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-DS.

[0106] (5) Accurately weigh 75 mg of potassium chloroplatinate and dissolve it in 50 mL of 1 M KOH. Using a mercuric oxide electrode as the reference electrode, set the deposition voltage to -1.5 V and the deposition time to 500 s. Dry the resulting sample in a vacuum drying oven at 40 °C for 24 h. The resulting product is the two-dimensional nickel-based sulfide-supported Pt single-atom catalyst, denoted as Pt. SA NiS2-HS and Pt SA NiS2-DS.

[0107] Example 4

[0108] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0109] (1) Accurately weigh 100 mg Ni(NO3)2·6H2O into a clean beaker, measure 12 mL of methanol and 0.85 mL of N,N-dimethylformamide and transfer them to the beaker. After sonication, transfer them to the lining of a 25 mL hydrothermal reactor. Place a 2*2.5 cm clean nickel foam NF sheet in the hydrothermal reactor and keep it at 151.5 °C for 550 min. After the reaction is complete, remove the sheet with tweezers and rinse it with deionized water and ethanol. Then, vacuum dry it at 40 °C to obtain Ni(OH)2.

[0110] (2) Place one piece of Ni(OH)2 precursor in a magnetic boat, place the magnetic boat in a tube furnace and heat it to 300°C at a rate of 3°C / min, and keep it in the air for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black NiO.

[0111] (3) Place 1g of sublimed sulfur S powder and the prepared NiO in the upstream and downstream of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-HS.

[0112] (4) Place 0.3g of sublimed sulfur S powder and clean foamed nickel NF in the upper and lower reaches of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-DS.

[0113] (5) Accurately weigh 75 mg of potassium chloroplatinate and dissolve it in 50 mL of 1 M KOH. Using a mercuric oxide electrode as the reference electrode, set the deposition voltage to -1.43 V and the deposition time to 300 s. Dry the resulting sample in a vacuum drying oven at 40 °C for 24 h. The resulting product is the two-dimensional nickel-based sulfide-supported Pt single-atom catalyst, denoted as Pt. SA NiS2-HS and Pt SA NiS2-DS.

[0114] Example 5

[0115] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0116] (1) Accurately weigh 100 mg Ni(NO3)2·6H2O into a clean beaker, measure 12 mL of methanol and 0.85 mL of N,N-dimethylformamide and transfer them to the beaker. After sonication, transfer them to the lining of a 25 mL hydrothermal reactor. Place a 2*2.5 cm clean nickel foam NF sheet in the hydrothermal reactor and keep it at 151.5 °C for 550 min. After the reaction is complete, remove the sheet with tweezers and rinse it with deionized water and ethanol. Then, vacuum dry it at 40 °C to obtain Ni(OH)2.

[0117] (2) Place one piece of Ni(OH)2 precursor in a magnetic boat, place the magnetic boat in a tube furnace and heat it to 300°C at a rate of 3°C / min, and keep it in the air for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black NiO.

[0118] (3) Place 1g of sublimed sulfur S powder and the prepared NiO in the upstream and downstream of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-HS.

[0119] (4) Place 0.3g of sublimed sulfur S powder and clean foamed nickel NF in the upper and lower reaches of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-DS.

[0120] (5) Accurately weigh 75 mg of potassium chloroplatinate and dissolve it in 50 mL of 1 M KOH. Using a mercuric oxide electrode as the reference electrode, set the deposition voltage to -1.43 V and the deposition time to 1000 s. Dry the resulting sample in a vacuum drying oven at 40 °C for 24 h. The resulting product is the two-dimensional nickel-based sulfide-supported Pt single-atom catalyst, denoted as Pt. SA NiS2-HS, with Pt SA NiS 2- DS.

[0121] Cut a 1*2cm piece from the nickel-based sulfide obtained in Examples 2, 3, 4, and 5. 2 The flakes are subjected to an electrolysis reaction to produce hydrogen in an alkaline environment of 1 M KOH.

[0122] Upon examination, no obvious particles were observed on the transmission electron microscope (TEM) images of Examples 2, 3, 4, and 5, indicating that the Pt single atoms were uniformly dispersed. Furthermore, the performance differences in alkaline water electrolysis between Examples 2, 3, and 5 were not significant, all falling within the error range compared to Example 1. The performance of Example 4 was slightly worse, possibly due to the shorter deposition time, resulting in a smaller number of deposited Pt single atoms.

[0123] Example 6

[0124] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0125] (1) Accurately weigh 100 mg Ni(NO3)2·6H2O into a clean beaker, measure 12 mL of methanol and 0.85 mL of N,N-dimethylformamide and transfer them to the beaker. After sonication, transfer them to the lining of a 25 mL hydrothermal reactor. Place a 2*2.5 cm clean nickel foam NF in the hydrothermal reactor and keep it at 120 °C for 550 min. After the reaction is complete, remove the flake with tweezers and rinse it with deionized water and ethanol. Then, vacuum dry it at 40 °C to obtain Ni(OH)2.

[0126] (2) Place one piece of Ni(OH)2 precursor in a magnetic boat, place the magnetic boat in a tube furnace and heat it to 300°C at a rate of 3°C / min, and keep it in the air for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black NiO.

[0127] (3) Place 1g of sublimed sulfur S powder and the prepared NiO in the upstream and downstream of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-HS.

[0128] (4) Accurately weigh 75 mg of potassium chloroplatinate and dissolve it in 50 mL of 1 M KOH. Using a mercuric oxide electrode as the reference electrode, set the deposition voltage to -1.43 V and the deposition time to 500 s. Dry the resulting sample in a vacuum drying oven at 40 °C for 24 h. The resulting product is a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst, denoted as Pt. SA NiS2-HS.

[0129] Example 7

[0130] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0131] (1) Accurately weigh 100 mg Ni(NO3)2·6H2O into a clean beaker, measure 12 mL of methanol and 0.85 mL of N,N-dimethylformamide and transfer them to the beaker. After sonication, transfer them to the lining of a 25 mL hydrothermal reactor. Place a 2*2.5 cm clean nickel foam NF in the hydrothermal reactor and keep it at 180 °C for 550 min. After the reaction is complete, remove the flakes with tweezers and rinse them with deionized water and ethanol. Then, vacuum dry them at 40 °C to obtain Ni(OH)2.

[0132] (2) Place one piece of Ni(OH)2 precursor in a magnetic boat, place the magnetic boat in a tube furnace and heat it to 300°C at a rate of 3°C / min, and keep it in the air for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black NiO.

[0133] (3) Place 1g of sublimed sulfur S powder and the prepared NiO in the upstream and downstream of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-HS.

[0134] (4) Accurately weigh 75 mg of potassium chloroplatinate and dissolve it in 50 mL of 1 M KOH. Using a mercuric oxide electrode as the reference electrode, set the deposition voltage to -1.43 V and the deposition time to 500 s. Dry the resulting sample in a vacuum drying oven at 40 °C for 24 h. The resulting product is a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst, denoted as Pt. SA NiS2-HS.

[0135] Example 8

[0136] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0137] (1) Accurately weigh 100 mg Ni(NO3)2·6H2O into a clean beaker, measure 12 mL of methanol and 0.85 mL of N,N-dimethylformamide and transfer them to the beaker. After sonication, transfer them to the lining of a 25 mL hydrothermal reactor and place a 2*2.5 cm clean nickel foam NF in the hydrothermal reactor. Keep it at 151.5 °C for 600 min. After the reaction is complete, use tweezers to remove the flakes and rinse them with deionized water and ethanol. Then, vacuum dry them at 40 °C to obtain Ni(OH)2.

[0138] (2) Place one piece of Ni(OH)2 precursor in a magnetic boat, place the magnetic boat in a tube furnace and heat it to 300°C at a rate of 3°C / min, and keep it in the air for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black NiO.

[0139] (3) Place 1g of sublimed sulfur S powder and the prepared NiO in the upstream and downstream of a tube furnace respectively. First, introduce protective gas N2 and continue for 2 hours. Then, increase the temperature to 300℃ at a heating rate of 3℃ / min and keep it at that temperature for 2 hours. After the tube furnace cools down to room temperature, take it out to obtain black nickel-based sulfide NiS2-HS.

[0140] (4) Accurately weigh 75 mg of potassium chloroplatinate and dissolve it in 50 mL of 1 M KOH. Using a mercuric oxide electrode as the reference electrode, set the deposition voltage to -1.43 V and the deposition time to 500 s. Dry the resulting sample in a vacuum drying oven at 40 °C for 24 h. The resulting product is a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst, denoted as Pt. SA NiS2-HS.

[0141] Cut a 1*2cm piece from the nickel-based sulfide obtained in Examples 6, 7, and 8. 2 The flakes are subjected to an electrolysis reaction to produce hydrogen in an alkaline environment of 1M KOH.

[0142] Testing revealed no significant difference in the performance of alkaline electrolyzed water between Examples 7 and 8, and no significant change in morphology, indicating good dispersibility of Pt single atoms.

[0143] Comparative Example 1

[0144] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0145] Example 1 was repeated, except that in step 5), the deposition time required for electrochemical deposition was 100 seconds.

[0146] Testing revealed that the Pt atom catalyst obtained in this comparative example exhibited reduced hydrogen evolution reaction performance.

[0147] This shows that when deposition occurs within a short period of time, the Pt single-atom catalyst obtained by deposition has a low concentration of exposed Pt atoms, which slows down the hydrogen evolution reaction process.

[0148] Comparative Example 2

[0149] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0150] Repeat Example 1, except that in step 5), the mass of potassium chloroplatinate is 25 mg.

[0151] Testing revealed that the Pt atom catalyst obtained in this comparative example exhibited reduced hydrogen evolution reaction performance.

[0152] This shows that when deposited in a low Pt concentration solution, the Pt single-atom catalyst obtained by deposition has a lower exposed Pt atom concentration, which slows down the hydrogen evolution reaction process.

[0153] Comparative Example 3

[0154] A method for preparing a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst includes the following steps:

[0155] Repeat Example 1, except that in step 5), the voltage relative to the mercury oxide electrode deposition is set to -1.2V.

[0156] Testing revealed that the Pt atom catalyst obtained in this comparative example exhibited reduced hydrogen evolution reaction performance.

[0157] It can be seen that when deposition is performed at low voltage, the migration rate of Pt atoms is reduced due to the low current intensity, resulting in a lower concentration of Pt single atoms loaded on the substrate material, which slows down the hydrogen evolution reaction process.

[0158] Comparative Example 4

[0159] Repeat Example 1, except that in step 3), the mass of S powder weighed is 1.2g.

[0160] Comparative Example 5

[0161] Repeat Example 1, except that in step 4), the mass of S powder weighed is 1.2g.

[0162] Tests showed that the Pt atom catalysts obtained in Comparative Example 4 and Comparative Example 5 exhibited reduced hydrogen evolution reaction performance.

[0163] Therefore, it can be seen that when the amount of S doped is higher than a certain level, the dissolution of S during electrolysis will reduce the migration rate of ions in the electrolyte, slow down the adsorption process of H*, and thus reduce the hydrogen evolution reaction performance.

[0164] Obviously, the above embodiments and comparative examples of the present invention are merely illustrative examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A two-dimensional nickel-based sulfide-supported Pt single-atom catalyst, comprising a support and an active center; characterized in that: The carrier is a nickel-based sulfide; the active center is Pt; Pt metal atoms are uniformly dispersed and loaded on the nickel-based sulfide; the Pt metal atoms exist in the form of single atoms; The preparation method of the two-dimensional nickel-based sulfide supported Pt single-atom catalyst includes the following steps: 1) Using nickel salt as a precursor, add organic medium and reducing agent, mix thoroughly to obtain mixture A; 2) Place the mixture A and the substrate material in a polytetrafluoroethylene-lined reactor for hydrothermal reaction; 3) After the hydrothermal reaction cools down, the LDH self-supporting material is obtained. It is then dried in a vacuum drying oven at 30-60℃ for 12-24 hours to obtain substrate material A. 4) The obtained substrate material A is calcined in air at 200-400℃ for 2-4 h to obtain substrate material B; 5) The obtained substrate material B and solid sulfur were calcined together under an inert gas atmosphere at 200-400℃ for 2-4 h to obtain substrate material C; 6) The obtained substrate material C was electrochemically deposited under alkaline conditions and then vacuum dried at 30-60℃ for 12-24 h to obtain a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst Pt. SA NiS2-HS; In step 1), the nickel salt is 50-100 mg of nickel nitrate hexahydrate, the organic medium is 10-15 mL of anhydrous methanol with a mass fraction of 99.9%, and the reducing agent is 0.5-1.0 mL of N,N dimethylformamide. In step 2), the substrate material is nickel foam, the hydrothermal reaction temperature is 120-180℃, and the hydrothermal reaction time is 500-600 min. In step 5), the calcination temperature is 250-350℃, and the heating rate is 2-4℃ / min; In step 5), the solid sulfur is sublimed sulfur, with a mass of 0.3-1.0 g; In step 5), the inert gas is nitrogen or argon; In step 6), the alkaline condition is 50-100 mg potassium chloroplatinate dispersed in 50-100 mL of 1M KOH electrolyte solution; the working electrode is a nickel-based sulfide support directly grown on nickel foam, the counter electrode is a carbon rod, and the reference electrode is Hg / HgO. In step 6), the electrochemical deposition is performed using the galvanochronous method, with the applied reversible hydrogen voltage range being [-0.576 V, -0.426 V] and the duration set to 300-1000 s.

2. A two-dimensional nickel-based sulfide-supported Pt single-atom catalyst, comprising a support and an active center; characterized in that: The carrier is a nickel-based sulfide; the active center is Pt; Pt metal atoms are uniformly dispersed and loaded on the nickel-based sulfide; the Pt metal atoms exist in the form of single atoms; The preparation method of the two-dimensional nickel-based sulfide supported Pt single-atom catalyst includes the following steps: 1) Calcine the base material D with solid sulfur at 200-400℃ in an inert gas atmosphere for 2-4 h to obtain base material E; 2) The obtained substrate material E was electrochemically deposited under alkaline conditions and then vacuum dried at 30-60℃ for 12-24 h to obtain a two-dimensional nickel-based sulfide-supported Pt single-atom catalyst Pt. SA NiS2-DS; In step 1), the substrate material D is nickel foam; In step 1), the solid sulfur is sublimed sulfur, with a mass of 0.3-1.0 g; In step 2), the alkaline conditions are 50-100 mg potassium chloroplatinate dispersed in 50-100 mL of 1M KOH electrolyte solution; the working electrode is a nickel-based sulfide support directly grown on nickel foam, the counter electrode is a carbon rod, and the reference electrode is Hg / HgO. In step 2), the electrochemical deposition is performed using the galvanochronometry method, with the applied reversible hydrogen voltage range being [-0.576 V, -0.426 V] and the duration set to 300-1000 s.

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