Graphene pore-confined platinum-based nanoparticle material and preparation method thereof

Abstract

The application discloses a kind of graphene pore limited platinum-based nanoparticle materials and preparation method thereof, belong to new energy material technical field.This method will graphene oxide powder be placed in the mixed solution of nitric acid and hydrogen peroxide, then wet oxidation etching treatment is carried out in steel autoclave, and etched graphene oxide is obtained;Etched graphene oxide powder is placed in ultrapure water, and suspension is obtained after ultrasonic stripping;Platinum precursor or and transition metal precursor are mixed with suspension in beaker constant-temperature stirring, and solid mixture is obtained after washing and drying;Then, solid mixture is calcined in inert atmosphere environment, and oxygen group of graphene oxide is removed and reduced into graphene, simultaneously, metal precursor is decomposed into metal atom, these atoms will nucleate and grow and form nanoparticle.Finally, these nanoparticle manufacture pore on graphene carrier, thereby limit the movement of nanoparticle, thereby alleviate catalytic deactivation, and the durability of catalyst is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a graphene pore-confined platinum-based nanoparticle material and a preparation method thereof, and belongs to the technical field of new energy materials. BACKGROUND

[0002] To achieve large-scale commercialization of proton exchange membrane fuel cells (PEMFCs), key challenges related to cost, durability, and power density must be overcome. The kinetics of the cathode oxygen reduction reaction (ORR), which determines the power output of PEMFCs, is extremely slow. Therefore, a large amount of scarce platinum is required to catalyze the ORR, which accounts for more than 40% of the cost of PEMFCs. To enable wider application of PEMFCs, it is highly desirable to significantly reduce the amount of platinum in the catalyst, which has prompted efforts to develop catalysts with lower value, higher activity, and greater durability. Carbon-supported platinum nanoparticles (NPs) are often used as PEMFC catalysts. One common strategy to improve catalyst performance is to increase the proportion of Pt atoms exposed on the surface of the particles by reducing the size of the PtNPs. However, small-sized PtNPs with high surface energy are more prone to sintering to form large particles, which leads to rapid performance degradation and poor durability during electrocatalytic reactions. PtNP aggregation is one of the main mechanisms leading to sintering, which refers to the migration of PtNPs under the action of Brownian motion, and the fusion of particles into larger particles on the surface under the driving force of reduced surface energy. The direct result of sintering is the disappearance of small-sized NPs and the increase in the volume of larger NPs, resulting in a loss of electrochemically active specific surface area. Unfortunately, sintering of carbon-supported metal-based NP catalysts is almost inevitable during catalytic reactions. Therefore, in order to improve the long-term durability of the catalyst, the interaction between the carbon support and the PtNPs must be enhanced to inhibit the migration and aggregation of the PtNPs, thereby slowing down the sintering of the PtNPs. Carbon pore confinement is an effective way to enhance the interaction between the support and the PtNPs and inhibit the migration and aggregation of the PtNPs. However, the design and preparation of carbon pore-confined PtNPs face the following two challenges: (1) how to design a suitable carbon support channel; and (2) how to place PtNPs in the carbon support channel. SUMMARY

[0003] To overcome the problems in the background art, the present application aims to provide a graphene pore-confined platinum-based nanoparticle material and a preparation method thereof. The method involves wet chemical oxidation etching treatment of graphene oxide powder in a steel autoclave, followed by heat treatment. During the heat treatment, the oxygen groups of the graphene oxide are removed and reduced to graphene. At the same time, the metal precursor is decomposed into metal atoms, which nucleate and grow to form nanoparticles. Finally, these nanoparticles create pores on the graphene support, thereby confining the movement of the nanoparticles.

[0004] To achieve the above object, the present application is realized by the following technical scheme:

[0005] A preparation method of graphene pore-confined platinum-based nanoparticle material, comprising the following steps:

[0006] (1) ultrasonic dispersion of graphene oxide in nitric acid solution and hydrogen peroxide to obtain a mixed solution, and then hydrothermal treatment to obtain a GO suspension;

[0007] (2) dialysis, centrifugation and drying of the GO suspension to obtain dried EGO;

[0008] (3) dissolution of the dried EGO in water to form an EGO suspension by ultrasonic treatment, mixing of platinum precursor or a mixed precursor of platinum precursor and transition metal precursor with the EGO suspension to obtain a platinum precursor and EGO mixture, and then centrifugation and freeze-drying to obtain a freeze-dried mixture;

[0009] (4) calcination of the freeze-dried mixture under inert gas to obtain graphene pore-confined platinum-based nanoparticle material.

[0010] More preferably, the graphene oxide is obtained by oxidation of graphite powder and / or carbon nanotubes using Hummers oxidation method, wherein the carbon nanotubes are single-walled or multi-walled carbon nanotubes with a tube diameter.

[0011] More preferably, the volume ratio of the nitric acid solution and hydrogen peroxide is 100:1-30:1, the concentration of the nitric acid solution is 1-10 mol / L, the concentration of the hydrogen peroxide is 30 wt%, and the concentration of the graphene oxide in the mixed solution is 1-10 mg / L.

[0012] More preferably, the hydrothermal treatment is carried out at a temperature of 50-90℃ for 9-20 h.

[0013] More preferably, in the step (2), the GO suspension is dialyzed using a dialysis bag with a cut-off of 14000 Da.

[0014] More preferably, the platinum precursor is dihydroxy tetraammine platinum, chloroplatinic acid, platinum acetylacetonate, platinum chloride, platinum nitrate, ethanolamine hydroxyl platinum, etc.; and the transition metal precursor is dihydroxy tetraammine copper, copper acetylacetonate, copper chloride, copper nitrate, copper sulfate, dihydroxy tetraammine cobalt, cobalt acetylacetonate, cobalt chloride, cobalt nitrate, cobalt sulfate.

[0015] More preferably, the mass ratio of the dried EGO to the platinum precursor is 20:1-2:1; the mass ratio of the dried EGO to the mixed precursor is 50:1-1:1; and the mass ratio of the platinum precursor to the transition metal precursor in the mixed precursor is 10:1-1:5.

[0016] More preferably, the temperature of the calcination is 800-1000℃, the time is 1-3h, and the heating rate is 10-30min.

[0017] The application also claims the graphene pore-confined platinum-based nanoparticle material prepared by the preparation method of the graphene pore-confined platinum-based nanoparticle material.

[0018] More preferably, the graphene pore-confined platinum-based nanoparticle material is such that the platinum-based nanoparticles are confined in the graphene pore holes.

[0019] The main principle of the application is as follows: after the oxidation graphite is exfoliated and deprotonated, a single-layer graphene oxide sol with negative charge is formed. The metal precursor and the single-layer graphene oxide sol are electrostatically adsorbed to obtain a composite of graphene oxide and the metal precursor. After heat treatment, the oxygen groups of the graphene oxide are removed and reduced to graphene. Meanwhile, during the heat treatment, the metal precursor is converted into metal atoms, and due to the high surface energy, the atoms nucleate and grow to form metal nanoparticles. In the growing process, the metal nanoparticles catalyze the reaction of carbon and oxygen on the graphene to generate carbon monoxide or carbon dioxide, thereby manufacturing pores on the graphene carrier. Finally, the nanoparticles are confined by the pores.

[0020] The application has the following beneficial effects:

[0021] (1) The application can simultaneously manufacture pores on the carbon carrier and put platinum-based nanoparticles into the pores, realize the confinement of the metal nanoparticles, inhibit the migration and aggregation of the metal nanoparticles during the electrocatalytic oxygen reduction reaction, thereby relieving the catalytic deactivation and improving the durability of the catalyst.

[0022] (2) The pores on the graphene carrier in the application are helpful to the mass transfer in the catalytic reaction, thereby enabling the catalyst to efficiently catalyze the oxygen reduction reaction.

[0023] (3) The method of the application has simple process, low requirement for equipment, low cost, and good industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The X-ray diffraction pattern of the graphene pore-confined platinum nanoparticle material prepared for Example 1 of the application.

[0025] Figure 2 The scanning electron microscope image of the graphene pore-confined platinum nanoparticle material prepared for Example 1 of the application.

[0026] Figure 3 The transmission electron microscope image of the graphene pore-confined platinum nanoparticle material prepared for Example 1 of the application.

[0027] Figure 4Comparison chart of electrocatalytic oxygen reduction reaction activity of graphene pore-confined platinum nanoparticle material prepared in Example 1 of the present application and commercial catalyst.

[0028] Figure 5 SEM chart of graphene pore-confined platinum nanoparticle material prepared in Example 2 of the present application.

[0029] Figure 6 Chart of electrocatalytic oxygen reduction reaction activity of graphene pore-confined platinum nanoparticle material prepared in Example 2 of the present application.

[0030] Figure 7 SEM chart of graphene pore-confined platinum nanoparticle material prepared in Example 3 of the present application.

[0031] Figure 8 Chart of electrocatalytic oxygen reduction reaction activity of graphene pore-confined platinum nanoparticle material prepared in Example 3 of the present application.

[0032] Figure 9 SEM chart of graphene pore-confined Pt-Cu nanoparticle material prepared in Example 4 of the present application.

[0033] Figure 10 Chart of electrocatalytic oxygen reduction reaction activity of graphene pore-confined platinum nanoparticle material prepared in Example 4 of the present application.

[0034] Figure 11 SEM chart of graphene pore-confined Pt-Co nanoparticle material prepared in Example 5 of the present application.

[0035] Figure 12 Chart of electrocatalytic oxygen reduction reaction activity of graphene pore-confined platinum nanoparticle material prepared in Example 5 of the present application. DETAILED DESCRIPTION

[0036] The present application will be further described in conjunction with specific examples, but the scope of protection of the present application is not limited thereto.

[0037] The graphene oxide used in the examples and comparative examples of the present application is obtained by oxidizing graphite powder using Hummers method.

[0038] Example 1

[0039] A preparation method of a graphene pore-confined platinum-based nanoparticle material, comprising the following steps:

[0040] (1) 500 mg of graphene oxide (GO) was placed in 50 mL of nitric acid (5 mol L -1 ) and 1.5 mL of hydrogen peroxide (30 wt%), and ultrasonic dispersion was performed for 1 h to obtain a suspension with a concentration of 9.7 mg mL -1 .

[0041] (2) The suspension was transferred into a stainless steel autoclave lined with 100 mL of polytetrafluoroethylene and kept at a temperature of 90 °C for 12 h to obtain an acid-etched GO (EGO) suspension.

[0042] (3) The EGO suspension was dialyzed using a dialysis bag with a cut-off of 14000 Da and then centrifuged (12000 rpm, 3 times, 10 min each time) and then transferred into a vacuum drying oven and dried at a temperature of 60 °C and a vacuum of 0.08 Pa for 12 h to obtain a muddy EGO.

[0043] (4) 500 mg of the dried EGO was dissolved in 100 mL of deionized water to form a 5.0 mg L -1 EGO suspension, and 190 mg of a platinum precursor (dihydroxy tetraammine platinum, [Pt(NH3)4](OH)2) was mixed with the EGO suspension, and a [Pt(NH3)4] 2+ / EGO mixture was obtained by magnetic stirring at a constant temperature of 30 °C for 24 h.

[0044] (5) The [Pt(NH3)4] 2+ / EGO mixture in step (4) was centrifuged (12000 rpm, 3 times, 10 min each time) and then the obtained mixture was dried in a freeze dryer.

[0045] (6) The freeze-dried mixture was calcined at 900 °C for 1.5 h in a nitrogen atmosphere to obtain a graphene pore-confined PtNPs material.

[0046] X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the graphene pore-confined PtNPs material, and it was confirmed that the graphene pore-confined PtNPs material was successfully prepared. In the XRD pattern Figure 1 , diffraction peaks appeared at 2θ = 39.6°, 46.0°, 67.3°, 81.1°, and 85.6°, corresponding to the diffraction of the (111), (200), (220), (311), and (222) crystal planes of Pt, respectively, indicating the presence of Pt crystals in the graphene pore-confined platinum-based nanomaterial. From the SEM Figure 2 , it can be seen that the Pt particles are distributed in the graphene pores. The TEM Figure 3 results show that Pt nanoparticles with an average particle size of 2.8 ± 0.7 nm are successfully confined by the graphene pores. The electrochemical test results are shown in Figure 4 and Table 1. It can be seen that the mass activity of the graphene pore-confined PtNPs material is 410 mA / mg Pt) higher than the mass activity (152 mA / mg of Pt / C catalyst of commercial catalyst, indicating that the material has good electrocatalytic oxygen reduction activity, and the material electrochemical test results are shown in Table 2. Pt

[0047] Example 2

[0048] A preparation method of a graphene pore-confined platinum-based nanoparticle material, comprising the following steps:

[0049] (1) 500 mg of graphene oxide (GO) is placed in 100 mL of nitric acid (10 mol / L -1 ) and 1.0 mL of hydrogen peroxide (30 wt%) and ultrasonically dispersed for 1 h to obtain a suspension with a concentration of 4.9 mg / mL -1 .

[0050] (2) The suspension is transferred to a stainless steel autoclave lined with 100 mL of polytetrafluoroethylene, and incubated at a temperature of 90°C for 12 h to obtain an acid-etched GO (EGO) suspension.

[0051] (3) The EGO suspension is dialyzed using a dialysis bag with a cut-off of 14000 Da, and then centrifuged (12000 rpm, 3 times, 10 min each time) using a centrifuge, and then transferred to a vacuum drying oven, dried at a vacuum degree of 0.08 Pa and a temperature of 60°C for 12 hours to obtain a muddy EGO.

[0052] (4) 500 mg of dried EGO is dissolved in 100 mL of deionized water to form an EGO suspension with a concentration of 5.0 mg / L -1 , and 390 mg of a platinum precursor (dihydroxy tetraammine platinum, [Pt(NH3)4](OH)2) is mixed with the EGO suspension, and by magnetic stirring at a constant temperature of 30°C for 24 h, a [Pt(NH3)4] 2+ / EGO mixture is obtained.

[0053] (5) The [Pt(NH3)4] 2+ / EGO mixture in step (4) is centrifuged (12000 rpm, 3 times, 10 min each time) using a centrifuge, and then the obtained mixture is transferred to a freeze dryer for drying.

[0054] (6) The freeze-dried mixture is calcined at 1000°C for 1 h in a nitrogen atmosphere to obtain a graphene pore-confined PtNPs material.

[0055] As Figure 5 ​As shown, the Pt particles in the graphene pore-confined Pt NPs material prepared in Example 2 are distributed in the graphene pores and successfully confined by the graphene pores, and the electrocatalytic oxygen reduction activity is as shown. Figure 6 The electrochemical test results of the material are shown in Table 1.

[0056] Example 3

[0057] A preparation method of a graphene pore-confined platinum-based nanoparticle material, comprising the following steps:

[0058] (1) 500 mg of graphene oxide (GO) is placed in 60 mL of nitric acid (5 mol L -1 ) and 2.0 mL of hydrogen peroxide (30 wt%) and ultrasonically dispersed for 1 h to obtain a suspension with a concentration of 8.0 mg mL -1 .

[0059] (2) The suspension is transferred to a stainless steel autoclave lined with 100 mL of polytetrafluoroethylene, and incubated at a temperature of 90°C for 9 h to obtain an acid-etched GO (EGO) suspension.

[0060] (3) The EGO suspension is dialyzed using a dialysis bag with a cut-off of 14000 Da, and then centrifuged (12000 rpm, 3 times, 10 min each time) using a centrifuge, and then transferred to a vacuum drying oven, and dried at a vacuum degree of 0.08 Pa and a temperature of 60°C for 12 hours to obtain a muddy EGO.

[0061] (4) 500 mg of dried EGO is dissolved in 100 mL of deionized water to form an EGO suspension with a concentration of 5.0 mg L -1 , and 180 mg of platinum precursor (dihydroxy tetraammine platinum, [Pt(NH3)4] (OH)2) is mixed with the EGO suspension, and a [Pt(NH3)4] 2+ / EGO mixture is obtained by magnetic stirring at a constant temperature of 30°C for 24 h.

[0062] (5) The [Pt(NH3)4] 2+ / EGO mixture in step (4) is centrifuged (12000 rpm, 3 times, 10 min each time) using a centrifuge, and then the obtained mixture is dried in a freeze dryer.

[0063] (6) The freeze-dried mixture is calcined at 800°C for 3 h in a nitrogen atmosphere to obtain a graphene pore-confined Pt NPs material.

[0064] As shown Figure 7As shown, the Pt particles in the graphene pore-confined PtNPs material prepared in Example 3 are distributed in the graphene pores and successfully confined by the graphene pores, and the electrocatalytic oxygen reduction activity is as shown. Figure 8 The electrochemical test results of the material are shown in Table 1.

[0065] Example 4

[0066] A preparation method of a graphene pore-confined platinum-based nanoparticle material, comprising the following steps:

[0067] (1) 51.5 mg of graphene oxide (GO) is placed in 50 mL of nitric acid (1 mol L -1 ) and 1.5 mL of hydrogen peroxide (30 wt%), and ultrasonic dispersion is performed for 1 h to obtain a suspension with a concentration of 1 mg mL -1 .

[0068] (2) The suspension is transferred to a stainless steel autoclave lined with 100 mL of polytetrafluoroethylene, and incubated at a temperature of 50°C for 20 h to obtain an acid-etched GO (EGO) suspension.

[0069] (3) The EGO suspension is dialyzed using a dialysis bag with a cut-off of 14000 Da, and then centrifuged (12000 rpm, a total of 3 times, 10 min each time) to obtain a muddy EGO.

[0070] (4) 500 mg of the dried EGO is dissolved in 100 mL of deionized water to form an EGO suspension with a concentration of 5.0 mg L -1 , and 180 mg of a platinum precursor (dihydroxy tetraammine platinum, [Pt(NH3)4](OH)2) and 180 mg of a copper precursor (dihydroxy tetraammine copper, [Cu(NH3)4](OH)2) are mixed with the EGO suspension, and a [Pt(NH3)4] 2+ / EGO mixture is obtained by magnetic stirring at a constant temperature of 30°C for 24 h.

[0071] (5) The [Pt(NH3)4] 2+ / EGO mixture in step (4) is centrifuged (12000 rpm, a total of 3 times, 10 min each time), and then the obtained mixture is transferred to a freeze dryer for drying.

[0072] (6) The freeze-dried mixture is calcined at 900°C for 1.5 h in a nitrogen atmosphere to obtain a graphene pore-confined Pt-CuNPs material.

[0073] As shown in Figure 9As shown, the Pt-Cu particles in the graphene pore-confined Pt-Cu NPs material prepared in Example 4 are distributed in the graphene pores and successfully confined by the graphene pores, and the electrocatalytic oxygen reduction activity is as shown. Figure 10 The electrochemical test results of the material are shown in Table 1.

[0074] Example 5

[0075] A preparation method of a graphene pore-confined platinum-based nanoparticle material, comprising the following steps:

[0076] (1) 500 mg of graphene oxide (GO) is placed in 50 mL of nitric acid (5 mol L -1 ) and 1.5 mL of hydrogen peroxide (30 wt%), and ultrasonic dispersion is performed for 1 h to obtain a suspension with a concentration of 9.7 mg mL -1 .

[0077] (2) The suspension is transferred to a stainless steel autoclave lined with 100 mL of polytetrafluoroethylene, and incubated at a temperature of 90°C for 12 h to obtain an acid-etched GO (EGO) suspension.

[0078] (3) The EGO suspension is dialyzed using a dialysis bag with a cut-off of 14000 Da, and then centrifuged (12000 rpm, 3 times, 10 min each time) to obtain a muddy EGO, which is then transferred to a vacuum drying oven and dried at a vacuum degree of 0.08 Pa and a temperature of 60°C for 12 h.

[0079] (4) 500 mg of the dried EGO is dissolved in 100 mL of deionized water to form an EGO suspension with a concentration of 5.0 mg L -1 , and 9 mg of a platinum precursor (dihydroxy tetraammine platinum, [Pt(NH3)4] (OH)2) and 1 mg of a cobalt precursor (dihydroxy tetraammine cobalt, [Co(NH3)4] (OH)2) are mixed with the EGO suspension, and a [Pt(NH3)4] 2+ / EGO mixture is obtained by magnetic stirring at a constant temperature of 30°C for 24 h.

[0080] (5) The [Pt(NH3)4] 2+ / EGO mixture in step (4) is centrifuged (12000 rpm, 3 times, 10 min each time) and then transferred to a freeze dryer to dry the obtained mixture.

[0081] (6) The freeze-dried mixture is calcined at 900°C for 1.5 h in a nitrogen atmosphere to obtain a graphene pore-confined Pt-Co NPs material.

[0082] As shown, Figure 11As shown, the Pt-Co particles in the graphene hole-confined Pt-Co NPs material prepared in Example 5 are distributed in the graphene holes and successfully confined by the graphene holes, and the electrocatalytic oxygen reduction activity is as shown. Figure 12 The electrochemical test results of the material are shown in Table 1.

[0083] Comparative Example 1

[0084] A preparation method of a graphene / platinum-based nanoparticle material, comprising the following steps:

[0085] (1) 500 mg of graphene oxide (GO) was placed in 50 mL of nitric acid (5 mol L -1 ) and 1.5 mL of hydrogen peroxide (30 wt%), and ultrasonic dispersion was performed for 1 h to obtain a suspension with a concentration of 9.7 mg mL -1 .

[0086] (2) The suspension was incubated at a temperature of 90°C for 12 h to obtain an acid-etched GO (EGO) suspension.

[0087] (3) The EGO suspension was dialyzed using a dialysis bag with a cut-off of 14000 Da, and then centrifuged (12000 rpm, 3 times, 10 min each time) to obtain a muddy EGO, which was then transferred to a vacuum drying oven and dried at a vacuum degree of 0.08 Pa and a temperature of 60°C for 12 hours.

[0088] (4) 500 mg of the dried EGO was dissolved in 100 mL of deionized water to form an EGO suspension with a concentration of 5.0 mg L -1 , and 390 mg of a platinum precursor (dihydroxy tetraammine platinum, [Pt(NH3)4](OH)2) was mixed with the EGO suspension, and a [Pt(NH3)4] 2+ / EGO mixture was obtained by magnetic stirring at a constant temperature of 30°C for 24 h.

[0089] (5) The [Pt(NH3)4] 2+ / EGO mixture in step (4) was centrifuged (12000 rpm, 3 times, 10 min each time), and then the obtained mixture was dried in a freeze dryer.

[0090] (6) The freeze-dried mixture was calcined at 900°C for 1.5 h in a nitrogen atmosphere to obtain a graphene / Pt NPs material. The electrochemical test results are shown in Table 1.

[0091] Comparative Example 2

[0092] A preparation method of a graphene / platinum-based nanoparticle material, comprising the following steps:

[0093] (1) Take 500 mg graphene dissolved in 100 mL deionized water, ultrasonic to form 5.0 mg L -1 EGO suspension, take 390 mg platinum precursor (dihydroxy tetraammine platinum, [Pt(NH3)4] (OH)2), mixed with EGO suspension, by constant temperature at 30℃ magnetic stirring for 24h, to get [Pt(NH3)4] 2+ / EGO mixture.

[0094] (2) Again use centrifuge to centrifuge [Pt(NH3)4] 2+ / EGO mixture in step (1) (12000 rpm, a total of 3 times, 10 min each time), and then transfer the obtained mixture to the freeze dryer for drying.

[0095] (3) The freeze-dried mixture is calcined at 900℃ for 1.5h in a nitrogen atmosphere to obtain graphene / Pt NPs material. The electrochemical test results of the material are shown in Table 1.

[0096] Table 1

[0097]

[0098] As can be seen from Table 1, the graphene pore-confined platinum-based nanoparticle materials prepared in Examples 1-5 have a mass activity decay rate at 0.6-0.9V after 30000 times of accelerated durability test (ADT 30K 0.6-0.95V) which is lower than that of Comparative Examples 1-2, fully demonstrating that the materials prepared by the present application have excellent durability. The new material prepared by the preparation method of the present application can confine platinum-based nanoparticles in carbon pores, effectively enhance the interaction between graphene and platinum-based nanoparticles, and at the same time, utilize the constraint of carbon pores on platinum-based nanoparticles to reduce the probability of migration, shedding and agglomeration of nanoparticles during long-term electrochemical reaction, ultimately improve the electrocatalytic activity and durability of graphene pore-confined platinum-based nanoparticle materials.

[0099] Finally, it should be pointed out that the above preferred embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present application.

Claims

1. A method of preparing a graphene pore-confined platinum-based nanoparticle material, characterized by: The method comprises the following steps: (1) dispersing graphene oxide in a mixed solution of nitric acid and hydrogen peroxide by ultrasonic to obtain a mixed solution, and then hydrothermally obtaining a GO suspension; (2) dialyzing, centrifuging and drying the GO suspension to obtain dried EGO; (3) dissolving the dried EGO in water, ultrasonically forming an EGO suspension, mixing a platinum precursor or a mixed precursor of a platinum precursor and a transition metal precursor with the EGO suspension to obtain a mixture of the platinum-based precursor and the EGO, and then centrifuging and freeze-drying the mixture to obtain a freeze-dried mixture; the transition metal precursor is dihydroxy tetraammine copper, copper acetylacetonate, copper chloride, copper nitrate, copper sulfate, dihydroxy tetraammine cobalt, cobalt acetylacetonate, cobalt chloride, cobalt nitrate or sulfuric acid; (4) calcining the freeze-dried mixture under an inert gas to obtain a graphene hole-confined platinum-based nanoparticle material.

2. The method for preparing graphene-confined platinum-based nanoparticles according to claim 1, characterized in that: The graphene oxide is obtained by oxidizing graphite powder and / or carbon nanotubes using the Hummers method, wherein the carbon nanotubes are single-walled or multi-walled carbon nanotubes.

3. The method for preparing graphene-confined platinum-based nanoparticles according to claim 1, characterized in that: The volume ratio of the nitric acid solution to hydrogen peroxide is 100:1-30:1, the concentration of the nitric acid solution is 1-10 mol / L, the concentration of the hydrogen peroxide is 30 wt%, and the concentration of the graphene oxide in the mixed solution is 1-10 mg / L.

4. The method for preparing graphene-confined platinum-based nanoparticles according to claim 1, characterized in that: The hydrothermal temperature is 50-90°C, and the hydrothermal time is 9-20 h.

5. The method for preparing graphene-confined platinum-based nanoparticles according to claim 1, characterized in that: In step (2), the GO suspension is dialyzed using a dialysis bag with a cut-off of 14,000 Da.

6. The method for preparing graphene-confined platinum-based nanoparticles according to claim 1, characterized in that: The platinum precursor is dihydroxy tetraammine platinum, chloroplatinic acid, platinum acetylacetonate, platinum chloride, platinum nitrate or ethanolamine hydroxyl platinum.

7. The method for preparing graphene-confined platinum-based nanoparticles according to claim 1, characterized in that: The mass ratio of the dried EGO to the platinum precursor is 20:1-2:1, and the mass ratio of the dried EGO to the mixed precursor is 50:1-1:

1. The mass ratio of the platinum precursor to the transition metal precursor in the mixed precursor is 10:1-1:

5.

8. The method for preparing graphene-confined platinum-based nanoparticles according to claim 1, characterized in that: The calcination temperature is 800-1000°C, the calcination time is 1-3 h, and the heating rate is 10-30 min.

9. The graphene hole-confined platinum-based nanoparticle material prepared by the method according to any one of claims 1-8.

10. The graphene nanopore confined platinum-based nanoparticle material of claim 9, wherein: The platinum-based nanoparticles are confined in the graphene hole.

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