Self-supporting nano-porous Pt-based intermetallic compound electrocatalyst as well as preparation method and application thereof

Abstract

According to the self-supporting nano-porous Pt-based intermetallic compound electrocatalyst and the preparation method and application thereof, electrochemical corrosion is adopted, a Pt-based alloy strip is subjected to electrochemical corrosion through the difference of oxidation potentials of Pt and transition metal (Cu, Fe, Ni and the like) in oxidizing acid, three-dimensional bicontinuous nano-porous Pt (Cu, Fe, Ni) is obtained, thermal reduction is conducted, and the self-supporting nano-porous Pt-based intermetallic compound electrocatalyst is obtained. The three-dimensional bicontinuous nano-porous Pt (Cu, Fe and Ni) intermetallic compound is obtained, and the active specific surface area is increased, so that more active sites are exposed, HER is promoted, and the stability of the catalyst is relatively good due to ordered atom arrangement.

Description

Technical field:

[0001] The present invention belongs to the technical field of electrocatalysis, and in particular relates to a self-supporting nanoporous PtCu intermetallic compound electrocatalyst and a preparation method and application thereof, which are used in the electrolysis of water to produce hydrogen. Background technology:

[0002] Hydrogen energy has the characteristics of zero pollution and zero carbon emissions, and is one of the most promising clean energy sources in the 21st century. At present, the main methods for producing hydrogen include thermochemical cycles, biomass conversion and water electrolysis. Among them, water electrolysis has become a key technology for the efficient use of renewable energy because it can use renewable energy such as wind energy and solar energy to produce hydrogen. In order to achieve efficient water electrolysis to produce hydrogen, it is necessary to develop electrocatalysts with strong activity, good stability and low cost. The precious metal Pt is currently the best performing water electrolysis hydrogen production catalyst with low overpotential, high current density and high stability, but its scarce resources and high price limit its large-scale application. Therefore, water electrolysis hydrogen production electrocatalysts with high catalytic activity, high stability and low cost are urgently needed. There are two main methods to improve the activity of electrocatalysts: one is to increase the number of active sites, and the other is to enhance its intrinsic activity. Increasing active sites can be achieved by constructing nanostructures: (such as nanoparticles, nanotubes, nanosheets and nanoporous structures), among which nanoporous structures are regarded as an ideal structure because of their high specific surface area and good mass transfer performance. The improvement of intrinsic activity can be achieved by alloying Pt with other non-precious metals, which can reduce the amount of Pt used. At the same time, the introduction of alloying elements can also adjust the d-band center of Pt, making it have a moderate hydrogen adsorption strength and improving intrinsic activity. PtCu alloy is regarded as an ideal substitute for the precious metal Pt due to its good compatibility with Cu, high electrochemical stability and low cost.

[0003] The existing nanoporous structure is mainly prepared by dealloying. Among the many dealloying methods, chemical dealloying is the simplest, but it cannot quantitatively control the ratio of Pt to transition metal in the material. The existing PtCu catalyst materials are mainly nanoparticles, which require the addition of binders, which will increase resistance, block active sites, and inhibit mass transfer, etc., which are problems with nanoparticle catalysts. In addition, the Cu in the PtCu alloy is easily dissolved and released in an acidic medium, resulting in a decrease in catalytic activity.

[0004] In view of the above difficulties, the present invention proposes a method for preparing a self-supporting nanoporous PtCu intermetallic compound by combining electrochemical dealloying with heat treatment. PtCu alloy is ordered to form a PtCu intermetallic compound. The ligand effect and strain effect generated by the ordered atomic arrangement can adjust the surface adsorption performance and structural stability of the material, thereby further improving the catalytic activity and cycle performance of the material. Combined with its morphological characteristics, the electrocatalytic hydrogen evolution reaction (HER) activity of the material is significantly improved. Summary of the invention:

[0005] The present invention aims to overcome the shortcomings of existing Pt-based HER catalytic materials and provide a self-supporting nanoporous Pt-based intermetallic compound electrocatalyst and its preparation method and application. The catalyst prepared by the present invention can be used as an electrode material to efficiently catalyze the electrolysis of water to produce hydrogen, and has the potential to be applied to other similar electrolysis catalytic systems.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a self-supporting nanoporous Pt-based intermetallic compound electrocatalyst, the steps of the preparation method are:

[0008] (1) Preparation of master alloy strips

[0009] According to the phase range of the intermetallic compound, the atomic ratio of Pt and a certain transition metal that can form a solid solution is simulated and calculated, high-purity metal Pt and the transition metal are weighed according to the atomic ratio, and a solid solution alloy is prepared by arc melting technology, and then a 10-15μm Pt-based alloy strip with the atomic ratio is prepared, and no pure metal phase appears in the XRD of the strip;

[0010] (2) Preparation of Nanoporous Pt-based Alloy Intermediates

[0011] The Pt-based alloy strip was cleaned, dried, and connected to an electrochemical workstation as a working electrode in a three-electrode system, with a platinum mesh as the counter electrode and a saturated calomel electrode (SHE) or Ag / AgCl electrode as the reference electrode. Electrochemical corrosion was performed in a five-port electrolytic cell with a 0.1 M strong acid solution as the electrolyte.

[0012] The electrochemical corrosion process is as follows: first, a constant current density of 0.5 mA / cm 2 Carry out corrosion to obtain a constant current density corrosion curve, find the slope mutation point of the curve, and use the voltage corresponding to the slope mutation point as the cut-off voltage; intermetallic compounds with different atomic ratios have different cut-off voltages;

[0013] The atomic ratio of the target intermetallic compound is set, and the constant current density is used for etching until the cut-off voltage is reached; then, the corresponding cut-off voltage is used as the constant potential voltage for constant potential etching until the current is lower than 5 μA, so that the interior of the alloy strip is corroded through to obtain a nanoporous Pt-based alloy intermediate, which is then cleaned and dried;

[0014] (3) Preparation of Nanoporous Intermetallic Compound Catalysts

[0015] The insulation temperature range is determined according to the atomic ratio of the target intermetallic compound within the phase region of the intermetallic compound; the dried nanoporous Pt-based alloy intermediate is heat-treated in an inert gas environment containing hydrogen, and the insulation temperature of the heat treatment is within the above-determined insulation temperature range; after the heat treatment, the temperature is quickly cooled to room temperature to obtain a nanoporous intermetallic compound catalyst.

[0016] Furthermore, the transition metal is at least one of Fe, Ni and Cu; and the atomic ratio of the PtCu intermetallic compound is 1:1, 3:1 or 1:3.

[0017] Furthermore, the specific process of the heat treatment is: the air flow is 1500SCCM of 5% H 2 / 95% Ar gas for half an hour, then heat to the insulation temperature at a heating rate of 10-20C° / min and keep warm for 1-30h.

[0018] Furthermore, the strong acid solution is nitric acid, sulfuric acid, hydrochloric acid or perchloric acid, and the concentration of hydrogen ions in the strong acid solution is 0.1M.

[0019] Furthermore, the atomic ratio of the PtCu intermetallic compound is 1:1, the cut-off voltage is 0.468V (vs. SHE), the insulation temperature is 650-750°C, and the insulation time is 1-4h.

[0020] In a second aspect, the present invention provides a method for preparing a self-supporting nanoporous Pt-based intermetallic compound electrocatalyst, the steps of the preparation method are:

[0021] (1) Preparation of master alloy strips

[0022] According to the phase range of the intermetallic compound, the atomic ratio of Pt and a certain transition metal that can form a solid solution is simulated and calculated, high-purity metal Pt and the transition metal are weighed according to the atomic ratio, and a solid solution alloy is prepared by arc melting technology, and then a 10-15μm Pt-based alloy strip with the atomic ratio is prepared, and no pure metal phase appears in the XRD of the strip;

[0023] (2) Preparation of Nanoporous Pt-based Alloy Intermediates

[0024] The Pt-based alloy strip was cleaned, dried and connected to an electrochemical workstation as the working electrode in a three-electrode system, with a platinum mesh as the counter electrode and a saturated calomel electrode (SHE) as the reference electrode. Electrochemical corrosion was performed in a five-port electrolytic cell with a 0.1 M strong acid solution as the electrolyte.

[0025] The electrochemical corrosion adopts electrochemical CV corrosion. The process of electrochemical CV corrosion is: when the atomic ratio of Pt to transition metal element is 1:1, the voltage range is -0.181V to 0.359V (vs. SHE), the scanning circle number is 3800-4200 circles, and the working electrode area is 0.85-0.92cm 2 ;

[0026] When the atomic ratio of Pt to transition metal elements is 3:1, the voltage range is -0.181V to 0.659V (vs. SHE), the scanning number is 3800-4200 circles, and the working electrode area is 0.7-0.8cm 2 ;

[0027] The interior of the alloy strip is corroded thoroughly to obtain a nanoporous Pt-based alloy intermediate, which is then cleaned and dried;

[0028] (3) Preparation of Nanoporous Intermetallic Compound Catalysts

[0029] The insulation temperature range is determined according to the atomic ratio of the target intermetallic compound within the phase region of the intermetallic compound; the dried nanoporous Pt-based alloy intermediate is heat-treated in an inert gas environment containing hydrogen, the insulation temperature of the heat treatment is within the above-determined insulation temperature range, and the temperature is quickly lowered to room temperature after the heat treatment to obtain a nanoporous intermetallic compound catalyst.

[0030] Furthermore, the heat treatment process is as follows: the air flow is 1500 SCCM of 10% H 2 / 90% Ar gas for half an hour, and then heat to the holding temperature at a heating rate of 10°C / min. When the atomic ratio of Pt to the transition metal element is 1:1, the holding time is 20-22h, and when the atomic ratio of Pt to the transition metal element is 3:1, the holding time is 24-26h.

[0031] In a third aspect, the present invention provides a self-supporting nanoporous Pt-based intermetallic compound catalyst obtained by the preparation method, wherein the self-supporting nanoporous Pt-based intermetallic compound catalyst has a three-dimensional bicontinuous structure, is an ordered structure with periodic changes, and has large pores and small pores.

[0032] Furthermore, at 0.5 MH 2 SO 4In the long-term hydrogen evolution reaction stability test, the nanoporous PtCu intermetallic compound material was -2 After continuous catalytic hydrogen evolution in an acidic environment for 16 hours, the overpotential can still be maintained at a low level, within 160mV.

[0033] The present invention also protects the use of the self-supporting nanoporous Pt-based metal intermetallic compound catalyst for electrocatalytic hydrogen evolution reaction, using the nanoporous Pt-based metal intermetallic compound catalyst as a working electrode, a carbon rod as a counter electrode, and an Ag / AgCl electrode as a reference electrode. 2 SO 4 Linear sweep voltammetry (LSV) test was performed in the test window of -0.597 to 0.003 V (vs. Ag / AgCl) and the scan rate was 10 mV·S -1 The activation process was CV activation, the test window was -0.197~1.003V (vs.Ag / AgCl), and the scan rate was 10mV·S -1 .

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention adopts electrochemical corrosion, utilizing the difference in oxidation potential between Pt and transition metals (Cu, Fe, Ni, etc.) in oxidizing acid, to electrochemically corrode Pt-based alloy strips to obtain three-dimensional bicontinuous nanoporous Pt (Cu, Fe, Ni), and then obtains three-dimensional bicontinuous nanoporous Pt (Cu, Fe, Ni) intermetallic compounds through thermal reduction, thereby increasing the active specific surface area, thereby exposing more active sites, which is beneficial to promoting the progress of HER, and the ordered atomic arrangement makes the catalyst more stable.

[0036] (2) The present invention can accurately obtain an alloy with a specific atomic ratio and a three-dimensional bicontinuous structure by controlling the current density during the dealloying process. The large pores are used for material transport and the small pores are used to increase the active area.

[0037] (3) The present invention obtains a PtCu ordered intermetallic compound catalyst, which minimizes the free energy between the constituent PtCu atoms, makes the active sites more specific and the structure more stable, thereby improving the catalytic activity and stability.

[0038] (4) The nanoporous PtCu intermetallic compound of the present invention is a self-supporting structure, which can avoid the effects of increased resistance, shielding of active sites and inhibition of mass transfer caused by the introduction of nafion resin in the spraying process of traditional materials. Description of the drawings:

[0039] Figure 1The precursor Pt 15 Cu 85 Electrochemical corrosion curve of the precursor Pt 15 Cu 85 (a) is the corrosion curve under constant current density; (b) is the corrosion curve under constant potential corrosion, at which the constant potential voltage is 0.468 V (vs. SHE).

[0040] Figure 2 It is the Pt-Cu phase diagram in the present invention, wherein the ordinate is temperature and the abscissa is Pt content.

[0041] Figure 3 It is a comparison diagram of the X-ray diffraction patterns of the nanoporous PtCu alloy intermediate and the nanoporous intermetallic compound in the present invention.

[0042] Figure 4 The scanning electron microscope comparison diagram of the nanoporous PtCu alloy intermediate (left) and the nanoporous intermetallic compound (right) in the present invention.

[0043] Figure 5 This is a HAADF-STEM comparison diagram of the lamellar internal structure of the nanoporous PtCu alloy intermediate and the nanoporous intermetallic compound in the present invention.

[0044] Figure 6 It is a comparison diagram of high-resolution transmission photographs of the nanoporous PtCu alloy intermediate and the nanoporous PtCu intermetallic compound in the present invention and the corresponding electron diffraction patterns.

[0045] Figure 7 This is a comparison chart of the HER performance of nanoporous PtCu alloy intermediates and nanoporous PtCu intermetallic compounds.

[0046] Figure 8 The current density of nanoporous PtCu intermetallic compound is 100mA / cm 2 Vt graph of 16-hour stability test.

[0047] Fig. 9 For nanoporous PtCu intermetallic compounds and at a current density of 100 mA / cm 2 Comparison of scanning electron micrographs of nanoporous PtCu intermetallic compounds grown under conditions of 16 hours. Specific implementation method:

[0048] The present invention is further explained below in conjunction with the embodiments and drawings, but this is not intended to limit the scope of protection of the present application.

[0049] Example 1

[0050] The steps of the preparation method of the self-supporting nanoporous PtCu intermetallic compound catalyst in this embodiment are:

[0051] (1)Pt 15 Cu 85 Preparation of master alloy strips

[0052] According to the phase range of the intermetallic compound, the suitable value of the atomic ratio of the two elements was simulated and calculated, and the high-purity metal Pt and metal Cu were prepared into a solid solution alloy by arc melting technology at an atomic ratio of 15:85. Then the alloy was placed in a quartz tube to prepare a PtCu alloy ingot. The surface oxide layer of the PtCu alloy ingot was removed, and the alloy ingot was heated to a molten state. Then, the molten PtCu alloy was used to prepare a Pt with a thickness of 10-15μm by a vacuum belt spinning device with Ar gas. 15 Cu 85 Strip, in which no pure metal phase appears in the XRD.

[0053] (2) Preparation of nanoporous PtCu alloy intermediates

[0054] The Pt prepared by ultrasonic cleaning with acetone and ultrapure water was 15 Cu 85 The master alloy strips were dried and connected to the Chenhua electrochemical workstation as the working electrode in the three-electrode system. The counter electrode was a platinum mesh and the reference electrode was a saturated calomel electrode (SHE). In a five-port electrolytic cell, 0.1 M HNO 3 It is an electrolyte for electrochemical corrosion;

[0055] The electrochemical corrosion process is as follows: first, a constant current density of 0.5 mA / cm 2 Carry out corrosion to obtain a constant current density corrosion curve, find the slope mutation point of the curve, and use the voltage corresponding to the slope mutation point as the cut-off voltage; intermetallic compounds with different atomic ratios have different cut-off voltages;

[0056] The atomic ratio of the target metal intermetallic compound is set to 1:1, and the constant current density is used to etch to the cut-off voltage; then the cut-off voltage is used as the constant potential voltage for constant potential etching until the current is less than 5μA. The control of the corrosion endpoint of the constant potential treatment can make the alloy sheet corrode through and etch into a three-dimensional bicontinuous structure.

[0057] After the etching was completed, the nanoporous PtCu alloy intermediate was obtained, which was washed four times with ultrapure water and dried naturally at room temperature.

[0058] (3) Preparation of Nanoporous Intermetallic Compound Catalysts

[0059] The dried nanoporous PtCu alloy intermediate was placed in a porcelain boat and then sent into a tube furnace for heat treatment in a hydrogen environment with a gas flow of 1500 SCCM of 5% H 2 / 95% Ar gas for half an hour, reduce the oxidized metal produced during electrochemical corrosion, and then heat up at a heating rate of 10-20C° / min to a holding temperature of 650-750°C for 1-4h. After the holding period, quickly cool to room temperature.

[0060] Figure 1 Figure (a) shows the precursor Pt 15 Cu 85 The electrochemical corrosion curve under constant current density can be found in the constant current density curve. The first mutation position is around 30000s, corresponding to a cut-off voltage of about 0.4V (vs. SHE), the second mutation position is around 38000s, corresponding to a cut-off voltage of about 0.468V (vs. SHE), and the third mutation position is around 42000s, corresponding to a cut-off voltage of about 0.9V (vs. SHE). Combined with the phase diagram, the corresponding cut-off voltage of intermetallic compounds with different atomic ratios can be determined. By controlling the cut-off piezoelectricity in constant current density corrosion, the proportion of PtCu can be quantitatively determined.

[0061] Figure 2 The figure is a phase diagram of PtCu, in which the ordinate is temperature and the abscissa is atomic ratio. From the phase diagram, the atomic ratio range of elements and the range of insulation temperature required for the prepared PtCu intermetallic compound can be determined. For example, when the Pt:Cu atomic ratio is 3:1, the insulation temperature is 600-650°C, and when the Pt:Cu atomic ratio is 1:3, the insulation temperature is 500-600°C.

[0062] Example 2

[0063] The atomic ratio of the target PtCu intermetallic compound in this embodiment is 1:1.

[0064] High-purity Pt and Cu spherical particles are made into Pt by arc melting technology according to the atomic ratio of 15:85. 15 Cu 85 alloy,

[0065] The alloy was then placed in a quartz tube to prepare a PtCu alloy ingot. The surface oxide layer of the PtCu alloy ingot was then removed, the ingot was cold rolled into a sheet with a thickness of 10 to 15 μm, and the prepared alloy strip was cut into 1x0.5 cm 2 spare.

[0066] Pt was ultrasonically cleaned with acetone and then ultrapure water.15 Cu 85 The strip was dried for 15 min and connected to an electrochemical workstation as the working electrode in a three-electrode system; the Pt mesh was used as the counter electrode; and saturated calomel was used as the reference electrode. 3 Electrochemical corrosion is carried out in the process, and the corrosion process is carried out in two steps:

[0067] (1) Constant current density corrosion, current density is 0.5mA / cm 2 , corroded to the cut-off voltage, the cut-off voltage is 0.468V (vs. SHE).

[0068] (2) Constant potential corrosion was performed with the cut-off voltage as the constant potential voltage and the corrosion time was 2 h. At this time, the current was less than 5 μA (see Figure 1 (b) shows that the interior of the alloy strip is corroded through.

[0069] After the etching was completed, a nanoporous PtCu alloy intermediate was obtained, which was then washed four times with ultrapure water and then dried naturally at room temperature.

[0070] Finally, the dried nanoporous PtCu alloy intermediate was placed in a porcelain boat and then sent into a tube furnace for thermal reduction with an air flow of 1500 SCCM of 5% H 2 / 95% Ar gas for half an hour, then heated to the insulation temperature at a heating rate of 20°C / min, the insulation temperature is 750°C, and the insulation time is 1h. After the insulation is completed, it is quickly cooled to obtain a nanoporous PtCu intermetallic compound catalyst with an atomic ratio of 1:1.

[0071] Figure 3 The precursor Pt prepared by the present invention 15 Cu 85 , nanoporous PtCu alloy and nanoporous PtCu intermetallic compound materials. The XRD diffraction patterns of the XRD patterns are compared with the standard PDF card. It can be found that there are no characteristic peaks of Pt and Cu in the XRD pattern of the precursor, so it is a solid solution, while the XRD pattern of the nanoporous PtCu alloy intermediate conforms to PDF (CuPt-NO.48-1549) and no superlattice peak appears, indicating that the nanoporous PtCu alloy intermediate is a disordered structure. The XRD pattern of the nanoporous PtCu intermetallic compound material conforms to PDF (CuPt-NO.42-1326), and the card has superlattice peaks (such as (021) crystal plane), indicating that the nanoporous intermetallic compound is an ordered structure, and from the XRD pattern, it can be seen that the prepared materials are pure phase precursor, PtCu alloy and PtCu intermetallic compound.

[0072] Figure 4The surface microstructure scanning electron microscope image and EDS image of the nanoporous PtCu alloy intermediate and the nanoporous intermetallic compound in the present invention show that the Pt and Cu elements are evenly distributed without Pt aggregation, and the atomic ratio of Pt:Cu is 1:1.

[0073] Figure 5 This is the HAADF-STEM image of the nanoporous PtCu alloy intermediate and the interior of the nanoporous intermetallic compound of the present invention. The transmission sample in the middle of the sheet material was prepared by the ion thinning method. It can be concluded that the material has a three-dimensional bicontinuous nanoporous structure. The entire sample is corroded through. From the figure, it can be found that there are large pores and small pores. The small pores increase the active specific surface area, while the large pores increase the mass transfer rate.

[0074] Figure 6 The high-resolution transmission electron microscope images (A1, B1) and electron diffraction patterns (A2, B2) of the nanoporous PtCu alloy intermediate and the nanoporous PtCu intermetallic compound in the present invention are analyzed. The high-resolution transmission electron microscope images and electron diffraction patterns show that the materials are nanoporous PtCu alloy intermediate and nanoporous PtCu intermetallic compound, respectively. By analyzing the lattice fringes and the electron diffraction pattern, it is found that the test XRD data is consistent, and the electron diffraction ring of the (021) crystal plane can also be found in the electron diffraction pattern of the nanoporous PtCu intermetallic compound, and the other crystal planes can also correspond one to one. There are no impurity diffraction rings in both, which once again proves that the intermetallic compound is an ordered structure and is a pure phase.

[0075] To test the catalytic activity of the materials, nanoporous PtCu alloy intermediates and nanoporous PtCu intermetallic compound catalysts were used as working electrodes, carbon rods as counter electrodes, and Ag / AgCl electrodes as reference electrodes. 2 SO 4 Linear sweep voltammetry (LSV) test was performed in the test window of -0.597~0.003V (vs.Ag / AgCl) and the scan rate was 10mV·S -1 The activation process was CV activation, the test window was -0.197~1.003V (vs.Ag / AgCl), and the scan rate was 10mV·S -1 The test results are as follows: Figure 7 As shown (experimental data after IR compensation).

[0076] The calculated current density of the nanoporous PtCu alloy intermediate is 100 mA cm -2 The overpotentials of the nanoporous PtCu intermetallic compound at a current density of 100 mA cm -2The overpotentials of the activated nanoporous PtCu intermetallic compounds are 275mV (before activation) and 97mV (after activation). -2 The overpotential is lower than that of nanoporous PtCu. The overpotential refers to the amount of electricity provided to produce the same amount of hydrogen. The lower the overpotential, the better the performance.

[0077] Figure 8 The nanoporous PtCu intermetallic compound material prepared in the present invention is heated to 0.5 MH 2 SO 4 The long-term hydrogen evolution reaction stability test results are shown in Figure 2. The nanoporous PtCu intermetallic compound material can react at a current density of 100 mA cm -2 After 16 hours of continuous catalytic hydrogen evolution in an acidic environment, the overpotential can still be kept low (about 160mV or less), while the intermediate product has a relatively high overpotential in the acidic environment. Within 16 hours, its average overpotential is greater than that of the intermetallic compound, indicating that the nanoporous PtCu intermetallic compound has good stability. And after the stability test of the nanoporous PtCu intermetallic compound, the nanoporous PtCu intermetallic compound did not release Cu, indicating that it has good corrosion resistance. The results are as follows Fig. 9 shown.

[0078] Example 3

[0079] The steps of this embodiment are the same as those of embodiment 2, except that the heating rate is changed to 10°C / min, the insulation temperature is changed to 650°C and the insulation time is 4h; the insulation temperature is changed to 700°C and the insulation time is 2h, and a self-supporting nanoporous PtCu intermetallic compound catalyst with an atomic ratio of 1:1 can be obtained.

[0080] Example 4

[0081] The atomic ratios of the target PtFe intermetallic compound in this embodiment are 1:1 and 3:1.

[0082] High-purity Pt and Fe spherical particles are made into Pt by arc melting technology according to the atomic ratio of 13.6:86.4. 13.6 Fe 86.4 The alloy was then placed in a quartz tube to prepare a PtFe alloy ingot. The surface oxide layer of the PtFe alloy ingot was then removed, the ingot was cold rolled into a sheet with a thickness of 10 μm, and the prepared alloy strip was cut into 1x0.5 cm 2 spare.

[0083] Pt was ultrasonically cleaned with acetone and then ultrapure water. 13.6 Fe 86.4The strip was dried for 15 min and connected to the electrochemical workstation as the working electrode in the three-electrode system; the Pt mesh was used as the counter electrode; and Ag\AgCl was used as the reference electrode. 2 SO 4 Electrochemical corrosion is carried out in the process, and the corrosion process is carried out in two steps:

[0084] 1) Constant current density corrosion, current density is 0.5mA / cm 2 , corroded to the cut-off voltage, the cut-off voltage is -0.15V (vs.Ag\AgCl) (atomic ratio 1:1) and 1.2V (vs.Ag\AgCl) (atomic ratio 3:1).

[0085] 2) Constant potential corrosion is carried out with the cut-off voltage as the constant potential voltage and the corrosion time is 2 hours. At this time, the current is lower than 5μA and the interior of the alloy strip is corroded through.

[0086] After the etching was completed, a nanoporous PtFe alloy intermediate was obtained, which was then washed four times with ultrapure water and then dried naturally at room temperature.

[0087] Finally, the dried nanoporous PtFe alloy intermediate was placed in a porcelain boat and then sent into a tube furnace for thermal reduction with an air flow of 1500 SCCM of 5% H 2 / 95% Ar gas for half an hour, then the heating rate is 20°C / min, the insulation temperature is 600°C, the insulation time is 1h, and after the insulation, it is quickly cooled to obtain nanoporous PtFe intermetallic compound catalysts with atomic ratios of 1:1 and 3:1.

[0088] Example 5

[0089] The atomic ratios of the target PtNi intermetallic compound in this embodiment are 1:1 and 3:1.

[0090] High-purity Pt and Ni spherical particles are made into Pt by arc melting technology according to the atomic ratio of 14:86. 14 Fe 86 The alloy is then placed in a quartz tube to prepare a PtNi alloy ingot. The surface oxide layer of the PtNi alloy ingot is then removed, the ingot is cold rolled into a sheet with a thickness of 10 to 15 μm, and the prepared alloy strip is cut into 1x0.5 cm 2 spare.

[0091] Pt was ultrasonically cleaned with acetone and then ultrapure water. 14 Fe 86 The strips were dried for 15 min and connected to an electrochemical workstation as the working electrode in a three-electrode system; the Pt mesh was used as the counter electrode; and saturated calomel (SHE) was used as the reference electrode.4 Perform electrochemical CV corrosion therein;

[0092] The specific parameters for the electrochemical CV corrosion process are set as follows: when the atomic ratio is 1:1, the voltage range is -0.181 V to 0.359 V (vs. SHE), the number of scanning cycles is 4000, and the working electrode area is 0.9 cm 2 ;

[0093] When the atomic ratio is 3:1, the voltage range is -0.181 V - 0.659 V (vs. SHE), the number of scanning cycles is 4000, and the working electrode area is 0.75 cm 2 . After the corrosion is completed, a nanoporous PtNi alloy intermediate is obtained, which is then washed 4 times with ultrapure water and then naturally dried at room temperature.

[0094] Finally, the dried nanoporous PtNi alloy intermediate is placed in a porcelain boat and then sent into a tube furnace for thermal reduction. After introducing a gas of 10% H 2 / 90% Ar at a flow rate of 1500 SCCM for half an hour, then a heating rate of 10 °C / min is carried out, the holding temperature is 600 °C, and the holding time is 20 h (atomic ratio 1:1), 24 h (atomic ratio 3:1). After the holding is completed, it is rapidly cooled to obtain nanoporous PtNi intermetallic compound catalysts with atomic ratios of 1:1 and 3:1.

[0095] All the above embodiments of the present invention have obtained self-supporting nanoporous Pt-based intermetallic compound catalysts with a three-dimensional bicontinuous structure.

[0096] Matters not described in the present invention are applicable to the prior art.

Claims

1. A method for preparing a self-supporting nanoporous Pt-based intermetallic compound electrocatalyst, characterized in that: The steps of the preparation method are: (1) Preparation of master alloy strips According to the phase range of the intermetallic compound, the atomic ratio of Pt and a certain transition metal that can form a solid solution is simulated and calculated, high-purity metal Pt and the transition metal are weighed according to the atomic ratio, and a solid solution alloy is prepared by arc melting technology, and then a 10-15μm Pt-based alloy strip with the atomic ratio is prepared, and no pure metal phase appears in the XRD of the strip; (2) Preparation of Nanoporous Pt-based Alloy Intermediates The Pt-based alloy strip was cleaned, dried, and connected to an electrochemical workstation as a working electrode in a three-electrode system, with a platinum mesh as the counter electrode and a saturated calomel electrode (SHE) or Ag / AgCl electrode as the reference electrode. Electrochemical corrosion was performed in a five-port electrolytic cell with a 0.1 M strong acid solution as the electrolyte. The electrochemical corrosion process is as follows: first, a constant current density of 0.5 mA / cm 2 Carry out corrosion to obtain a constant current density corrosion curve, find the slope mutation point of the curve, and use the voltage corresponding to the slope mutation point as the cut-off voltage; intermetallic compounds with different atomic ratios have different cut-off voltages; The atomic ratio of the target intermetallic compound is set, and the constant current density is used for etching until the cut-off voltage is reached; then, the corresponding cut-off voltage is used as the constant potential voltage for constant potential etching until the current is lower than 5 μA, so that the interior of the alloy strip is corroded through to obtain a nanoporous Pt-based alloy intermediate, which is then cleaned and dried; (3) Preparation of Nanoporous Intermetallic Compound Catalysts The insulation temperature range is determined according to the atomic ratio of the target intermetallic compound within the phase region of the intermetallic compound; the dried nanoporous Pt-based alloy intermediate is heat-treated in an inert gas environment containing hydrogen, and the insulation temperature of the heat treatment is within the above-determined insulation temperature range; after the heat treatment, the temperature is quickly cooled to room temperature to obtain a nanoporous intermetallic compound catalyst.

2. The preparation method according to claim 1, characterized in that: The transition metal is at least one of Fe, Ni and Cu; the atomic ratio of the PtCu intermetallic compound is 1:1, 3:1 or 1:

3.

3. The preparation method according to claim 1, characterized in that: The specific process of the heat treatment is: after introducing 5% H2 / 95% Ar gas with a gas flow of 1500 SCCM for half an hour, the temperature is increased to the insulation temperature at a heating rate of 10-20C° / min, and the temperature is maintained for 1-30 hours.

4. The preparation method according to claim 1, characterized in that: The strong acid solution is nitric acid, sulfuric acid, hydrochloric acid or perchloric acid, and the concentration of hydrogen ions in the strong acid solution is 0.1M.

5. The preparation method according to claim 2, characterized in that: The atomic ratio of the PtCu intermetallic compound is 1:1, the cut-off voltage is 0.468V (vs. SHE), the insulation temperature is 650-750°C, and the insulation time is 1-4h.

6. A method for preparing a self-supporting nanoporous Pt-based intermetallic compound electrocatalyst, characterized in that: The steps of the preparation method are: (1) Preparation of master alloy strips According to the phase range of the intermetallic compound, the atomic ratio of Pt and a certain transition metal that can form a solid solution is simulated and calculated, high-purity metal Pt and the transition metal are weighed according to the atomic ratio, and a solid solution alloy is prepared by arc melting technology, and then a 10-15μm Pt-based alloy strip with the atomic ratio is prepared, and no pure metal phase appears in the XRD of the strip; (2) Preparation of Nanoporous Pt-based Alloy Intermediates The Pt-based alloy strip was cleaned, dried and connected to an electrochemical workstation as the working electrode in a three-electrode system, with a platinum mesh as the counter electrode and a saturated calomel electrode (SHE) as the reference electrode. Electrochemical corrosion was performed in a five-port electrolytic cell with a 0.1 M strong acid solution as the electrolyte. The electrochemical corrosion adopts electrochemical CV corrosion. The process of electrochemical CV corrosion is: when the atomic ratio of Pt to transition metal element is 1:1, the voltage range is -0.181V to 0.359V (vs. SHE), the scanning circle number is 3800-4200 circles, and the working electrode area is 0.85-0.92cm 2 ; When the atomic ratio of Pt to transition metal elements is 3:1, the voltage range is -0.181V to 0.659V (vs. SHE), the scanning number is 3800-4200 circles, and the working electrode area is 0.7-0.8cm 2 ; The interior of the alloy strip is corroded thoroughly to obtain a nanoporous Pt-based alloy intermediate, which is then cleaned and dried; (3) Preparation of Nanoporous Intermetallic Compound Catalysts The insulation temperature range is determined according to the atomic ratio of the target intermetallic compound within the phase region of the intermetallic compound; the dried nanoporous Pt-based alloy intermediate is heat-treated in an inert gas environment containing hydrogen, the insulation temperature of the heat treatment is within the above-determined insulation temperature range, and the temperature is quickly lowered to room temperature after the heat treatment to obtain a nanoporous intermetallic compound catalyst.

7. The preparation method according to claim 6, characterized in that: The heat treatment process is: after introducing 10% H2 / 90% Ar gas with a gas flow of 1500SCCM for half an hour, the temperature is increased to the holding temperature at a heating rate of 10°C / min. When the atomic ratio of Pt to the transition metal element is 1:1, the holding time is 20-22 hours, and when the atomic ratio of Pt to the transition metal element is 3:1, the holding time is 24-26 hours.

8. A self-supporting nanoporous Pt-based intermetallic compound catalyst obtained by the preparation method according to any one of claims 1 to 7, characterized in that: The self-supporting nanoporous Pt-based intermetallic compound catalyst has a three-dimensional bicontinuous structure, which is an ordered structure with periodic changes and has large pores and small pores.

9. The catalyst according to claim 8, characterized in that In the long-term hydrogen evolution reaction stability test in 0.5M H2SO4, the nanoporous PtCu intermetallic compound material has a high stability at a current density of 100mA·cm -2 After continuous catalytic hydrogen evolution in an acidic environment for 16 hours, the overpotential can still be maintained at a low level, within 160mV.

10. Use of the self-supporting nanoporous Pt-based intermetallic compound catalyst according to claim 8, characterized in that: For electrocatalytic hydrogen evolution reaction, a nanoporous Pt-based intermetallic compound catalyst was used as the working electrode, a carbon rod was used as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. Linear sweep voltammetry (LSV) test was performed in 0.5M H2SO4; the test window was -0.597~0.003V (vs.Ag / AgCl), and the scan rate was 10mV·S -1 The activation process was CV activation, the test window was -0.197~1.003V (vs.Ag / AgCl), and the scan rate was 10mV·S -1 .

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