Preparation method and application of porous platinum / molybdenum carbide-nitrogen doped carbon composite catalyst

Abstract

The invention belongs to the technical field of electro-catalytic materials, and particularly relates to a preparation method and application of a porous platinum / molybdenum carbide-nitrogen doped carbon composite catalyst for producing hydrogen by electrolyzing water. The invention discloses a preparation method of a porous Pt / Mo2C-NC composite catalyst which is simple and convenient in process and low in cost, the problems of low precious metal utilization rate and poor stability in a traditional catalyst are solved by accurately regulating and controlling the dispersity and interface interaction of bimetallic components, and the prepared catalyst realizes efficient catalysis of a hydrogen evolution reaction of electrolyzed water; the overpotential of the prepared porous platinum / molybdenum carbide-nitrogen doped carbon catalyst is 62.1 mV when the current density is 10 mA / cm in an acidic electrolyte (such as 0.5 M H2SO4), and the stability is greater than 96% after 2000 cycles.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic materials, and specifically relates to a preparation method and application of a porous platinum / molybdenum carbide-nitrogen-doped carbon composite catalyst for electrolysis of water to produce hydrogen. Background Art

[0002] With the increasing demand for global energy transformation, hydrogen production from water electrolysis, a core technology for green hydrogen production, hinges on the development of low-cost, high-performance electrocatalysts to replace scarce precious metal platinum (Pt) catalysts. Molybdenum carbide (Mo2C) is an ideal non-precious metal catalytic component due to its platinum-like D-band electronic structure and excellent chemical stability. However, single Mo2C suffers from issues such as insufficient active site exposure and limited conductivity. When Mo2C is combined with a small amount of Pt to form a bimetallic system, a synergistic effect can be achieved: the D-band broadening properties of Mo2C optimize hydrogen adsorption energy, while Pt further enhances reaction kinetics through electron transfer. Furthermore, the high hardness and chemical stability of Mo2C inhibit the aggregation and dissolution of Pt nanoparticles, thereby reducing the amount of Pt required while maintaining excellent catalytic performance. In addition, the nitrogen-doped carbon (NC) support can significantly improve the electron transfer efficiency and active site density of the catalyst through its porous structure and nitrogen atom doping, further enhancing the performance of the composite catalyst: on the one hand, the three-dimensional porous network provides a higher specific surface area, which not only increases the exposure of active sites, but also promotes the rapid penetration of the electrolyte into the interior of the catalyst; on the other hand, the introduction of nitrogen atoms adjusts the charge distribution at the Pt / Mo2C interface through electronic effects, forming a strong metal-support interaction (SMSI), effectively inhibiting the dissolution and migration of precious metals in the reaction. At the same time, the nitrogen site itself can also act as an auxiliary active center to participate in the hydrogen evolution reaction.

[0003] In the prior art, catalyst preparation often uses complex multi-step processes or relies on toxic reagents. Multi-step processes (such as impregnation and precipitation) require precise control of parameters (pH, temperature, and calcination conditions) at each stage, resulting in high energy consumption and low yields. They may also use cyanide, organic solvents (such as DMF), or heavy metals (such as chromates) as precursors, posing environmental and safety risks. Furthermore, traditional processes struggle to precisely control the nanoscale dispersion of Pt and Mo2C. Summary of the Invention

[0004] The present invention achieves uniform anchoring of Pt particles (particle size 2-5 nm) in the Mo2C-NC support through a two-step impregnation method combined with an argon-hydrogen reduction process. At the same time, the strong metal-support interaction (SMSI) of nitrogen-doped carbon is utilized to inhibit Pt dissolution, significantly improving the catalytic performance.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The first aspect of the present invention discloses a method for preparing a porous platinum / molybdenum carbide-nitrogen-doped carbon (Pt / Mo2C-NC) catalyst, comprising the following steps: (1) impregnating the pretreated porous carbon support in an aqueous solution of molybdate and ultrasonically treating the porous carbon support, and then freeze-drying the porous carbon support to obtain dry molybdate-impregnated porous carbon; (2) Grinding the molybdate-impregnated porous carbon and melamine dried in (1) at a mass ratio of molybdate-impregnated porous carbon to melamine of 1:1-1:10 until the mixture is uniformly mixed to obtain a mixed sample; (3) The mixed sample in (2) was placed in an inert gas atmosphere, calcined at high temperature, cooled to room temperature, and collected to obtain a Mo2C-NC carrier; (4) impregnating the Mo2C-NC support in (3) in an aqueous solution of a platinum group noble metal salt and ultrasonically treating the support, and then freeze-drying the support to obtain a dry platinum salt-impregnated Mo2C-NC support; (5) The platinum salt-impregnated Mo2C-NC carrier dried in (4) was placed in a 5% hydrogen / argon atmosphere (argon-hydrogen mixed atmosphere, with a hydrogen volume fraction of 5%), heat treated at 200-500°C for 2 h, and then cooled to room temperature to obtain a porous platinum / molybdenum carbide-nitrogen-doped carbon (Pt / Mo2C-NC) composite catalyst.

[0006] Furthermore, in step (1), the pretreated porous carbon support is treated by heat treating the porous carbon support at 800°C for 2 h under the protection of an inert gas to remove surface impurities and adsorbed water, thereby obtaining a pretreated porous carbon support. The porous carbon support provides a high specific surface area, high electronic conductivity, and abundant catalytic sites.

[0007] Furthermore, in step (1), the molybdate is a combination of one or more of ammonium molybdate, ammonium dimolybdate, ammonium octamolybdate, ammonium molybdate tetrahydrate, ammonium heptamolybdate hydrate, and ammonium tetramolybdate dihydrate; Furthermore, the mass ratio of the molybdate to the porous carbon support is 1:3-5.

[0008] Furthermore, in step (1), the specific method of ultrasonic treatment and freeze drying is as follows: the impregnated carbon support is ultrasonicated in an ultrasonic device for 1 hour, and then placed in a freeze dryer, with a pre-freezing temperature of -50°C, a pre-freezing time of 3 hours, a vacuum degree of 20 Pa, and a drying time of 24 hours; Preferably, the ultrasonic treatment is carried out at a temperature of 25° C., the power of the ultrasonic device is 150 W, and the frequency of the ultrasonic wave is 25 kHz.

[0009] Furthermore, in step (2), the grinding is mechanical grinding, and a ball mill or an agate mortar is used for mechanical grinding.

[0010] Furthermore, in step (3), the high temperature calcination conditions are: calcination temperature 600-900°C, time is 2 h.

[0011] Furthermore, in step (4), the platinum group metal source in the platinum group noble metal salt includes: dichloride, trichloride, tetrachloride, and nitrate of ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), and platinum (Pt), Or a hydrochloric acid tetrachloride hydrate containing a platinum group metal element: such as one or more of chloroplatinic acid, chloroiridic acid, and chlororhodic acid; wherein other platinum group noble metal salts can be introduced into the chloroplatinic acid solution to form a noble metal alloy catalyst; The platinum group metal loading in the platinum group noble metal salt is 5-15wt%, preferably 10wt%; Competitive adsorbents are introduced into the aqueous solution of the platinum group metal salt, including one or more of methanol, ethanol, ethylene glycol, isopropyl alcohol, citric acid, tartaric acid, lactic acid, oxalic acid, formic acid, acetic acid, trichloroacetic acid, hydrochloric acid, polyethylene glycol, cetyl ammonium chloride, sodium dodecylbenzenesulfonate, and the like. Appropriate introduction of competitive adsorbents into the aqueous solution facilitates the dispersion of the precious metal nanoparticles and controls particle size.

[0012] Furthermore, in step (4), the specific method of ultrasonic treatment and freeze drying is as follows: the impregnated carbon support is ultrasonicated in an ultrasonic device for 1 hour, and then placed in a freeze dryer, with a pre-freezing temperature of -50°C, a pre-freezing time of 3 hours, a vacuum degree of 20 Pa, and a drying time of 24 hours; Preferably, the ultrasonic treatment is carried out at a temperature of 25° C., the power of the ultrasonic device is 150 W, and the frequency of the ultrasonic wave is 25 kHz.

[0013] The second aspect of the present invention discloses a porous platinum / molybdenum carbide-nitrogen-doped carbon (Pt / Mo2C-NC) catalyst, which is prepared by the above preparation method.

[0014] The third aspect of the present invention discloses the use of the above-mentioned porous platinum / molybdenum carbide-nitrogen-doped carbon (Pt / Mo2C-NC) catalyst in hydrogen production by water electrolysis.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention discloses a method for preparing a porous Pt / Mo2C-NC composite catalyst with simple process and low cost. By precisely controlling the dispersibility and interfacial interaction of the bimetallic components, the problem of low precious metal utilization and poor stability in traditional catalysts is solved. The prepared catalyst can achieve efficient catalysis in the hydrogen evolution reaction by water electrolysis.

[0016] 2. The present invention achieves nano-level uniform dispersion of Pt and Mo2C through a one-time impregnation-carbonization method of porous carbon, ammonium molybdate, and melamine and a platinum salt impregnation combined with an argon-hydrogen reduction process, thereby avoiding the use of complex processes and toxic reagents.

[0017] 3. The present invention achieves uniform anchoring of Pt nanoparticles (particle size 2-5 nm) on a porous molybdenum carbide / nitrogen-doped carbon support (Mo2C-NC) through a two-step impregnation method combined with an argon-hydrogen reduction process. At the same time, the strong metal-support interaction (SMSI) of nitrogen-doped carbon is utilized to inhibit Pt dissolution, significantly improving the catalytic performance. This has important practical significance for the development of low-cost, high-performance, low-platinum-based composite catalysts.

[0018] 4. The porous platinum / molybdenum carbide-nitrogen-doped carbon catalyst prepared by the present invention has an overpotential of 62.1 mV at a current density of 10 mA / cm² in an acidic electrolyte (such as 0.5 M H2SO4), and a stability of >96% after 2000 cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the two-step impregnation process for preparing porous Pt / Mo2C-NC composite catalyst; Figure 2 X-ray diffraction (XRD) patterns of the Mo2C-NC supports prepared in Example 1 and Examples 6-8; Figure 3 Scanning electron microscopy (SEM) image of the porous carbon support EC600JD; Figure 4 Example 1 SEM image of porous Mo2C-NC composite carbon support; Figure 5 SEM image of the Pt / Mo2C-NC composite catalyst of Example 9; Figure 6 Example 9 Transmission electron microscopy (TEM) image of Pt / Mo2C-NC composite catalyst; Figure 7 Comparative Example 1 TEM image of Pt-NC composite catalyst. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and examples, but the present invention is not limited to the scope of the examples. The process parameters not specified in the examples of this application can be carried out according to conventional methods, and the raw materials used can be obtained through commercial channels.

[0021] The present invention discloses a method for preparing a porous Pt / Mo2C-NC composite catalyst, wherein the process flow chart is shown in FIG. Figure 1 .

[0022] Example 1 Preparation of porous Mo2C-NC composite support: (1) The Ketjen Black EC600JD carbon support was heat treated at 800 °C for 2 h under nitrogen protection to remove surface impurities and adsorbed water. The SEM image of the pretreated carbon support was obtained as shown in the figure below. Figure 3 shown.

[0023] (2) Take 0.2 g of the pretreated carbon support EC600J and soak it in an aqueous solution containing 1 g of ammonium molybdate tetrahydrate (solution volume 4 mL, the liquid volume immerses the support), and place it in an ultrasonic device for 1 hour; the ultrasonic treatment is carried out at a temperature of 25°C, the power of the ultrasonic device is 150 W, and the frequency of the ultrasonic wave is 25 kHz. Then, it is placed in a freeze dryer with a pre-freezing temperature of -50°C, a pre-freezing time of 3 hours, a vacuum degree of 20 Pa, and a drying time of 24 hours to obtain dry ammonium molybdate-impregnated porous carbon.

[0024] (3) Dry ammonium molybdate-impregnated porous carbon and melamine are mechanically ground at a mass ratio of ammonium molybdate-impregnated porous carbon to melamine of 1:5 until the mixture is uniformly mixed.

[0025] (4) The mixed sample was placed in an inert gas atmosphere and calcined at 900 °C for 2 h. The temperature was then cooled to room temperature. The sample was collected as a Mo2C-NC carrier. The SEM image of the Mo2C-NC carrier is shown in Figure 2. Figure 4 As shown; Example 2 Compared with Example 1, in step (3), the porous carbon impregnated with ammonium molybdate and melamine are mechanically ground in a mass ratio of 1:1 until the mixture is uniformly mixed. Other aspects are the same as those in Example 1.

[0026] Example 3 Compared with Example 1, in step (3), the porous carbon impregnated with ammonium molybdate and melamine are mechanically ground in a mass ratio of 1:3 until the mixture is uniformly mixed. Other aspects are the same as those in Example 1.

[0027] Example 4 Compared with Example 1, in step (3), the porous carbon impregnated with ammonium molybdate and melamine is mechanically ground in a mass ratio of 1:8 until the mixture is uniformly mixed. Other aspects are the same as those in Example 1.

[0028] Example 5 Compared with Example 1, in step (3), the porous carbon impregnated with ammonium molybdate and melamine was mechanically ground in a mass ratio of 1:10 until the mixture was uniformly mixed. Other aspects were the same as in Example 1.

[0029] Table 1 XPS atomic ratios of Examples 1 to 5

[0030] In Examples 1 to 5, the nitrogen doping ratio in the Mo2C-NC support was adjusted by adjusting the carbon support:melamine mass ratio through the calcination temperature. As the carbon support:melamine mass ratio varied from 1:1, 1:3, and 1:5, the nitrogen doping ratio in the Mo2C-NC support increased from low to high. When the nitrogen doping ratio in the Mo2C-NC support reached approximately 8%, increasing the melamine dosage (i.e., the carbon support:melamine mass ratio varied from 1:5, 1:8, and 1:10) did not significantly change the nitrogen doping ratio in the Mo2C-NC support, indicating that the support's nitrogen adsorption capacity may have reached its limit.

[0031] When the amount of N doping increases, the proportion of C decreases from 67.9 at% (1:1) to 63.0 at% (1:8), indicating that N atoms may partially replace C in the carbon skeleton. The appropriate amount of N doping (~8 at%) can not only optimize electronic conduction but also will not excessively damage the conductive network of the carbon support. Example 6 Compared with Example 1, the calcination temperature in step (4) of this embodiment is adjusted to 800°C, and the rest is the same as that of Example 1.

[0032] Example 7 Compared with Example 1, the calcination temperature in step (4) of this embodiment is adjusted to 700°C, and the rest is the same as Example 1.

[0033] Example 8 Compared with Example 1, the calcination temperature in step (4) of this embodiment is adjusted to 600°C, and the rest is the same as that of Example 1.

[0034] In Examples 6 to 8, the calcination temperature was adjusted (600°C, 700°C, 800°C) to adjust the crystalline phase of Mo2C in the Mo2C-NC support. Figure 2 The XRD patterns of the Mo2C-NC supports prepared in Examples 1 and 6-8 show that as the calcination temperature increases from 600°C to 900°C, the crystalline phase of Mo2C gradually transforms from tetragonal molybdenum carbide (α-Mo2C) to hexagonal molybdenum carbide (β-Mo2C). β-Mo2C has the characteristics of high intrinsic activity and excellent stability, especially after loading precious metals. Therefore, the calcination condition of 900°C is more suitable.

[0035] Example 9 Preparation of porous Pt / Mo2C-NC composite catalyst (1) 0.2 g of the Mo2C-NC support in Example 1 was again immersed in an aqueous solution (solution volume 4 mL) containing 0.06 g of chloroplatinic acid hexahydrate (Pt loading 10 wt%). The impregnated Mo2C-NC support was then ultrasonicated in an ultrasonic device for 1 h and then placed in a freeze dryer with a pre-freezing temperature of -50 °C, a pre-freezing time of 3 h, a vacuum degree of 20 Pa, and a drying time of 24 h to obtain a precursor of a dry platinum salt-impregnated Mo2C-NC support. (2) The Mo2C-NC carrier was impregnated with dry platinum salt and placed in a 5% hydrogen / argon atmosphere at 200 °C for 2 h. The temperature was then cooled to room temperature. The SEM and TEM images of the sample were collected as porous platinum / molybdenum carbide-nitrogen-doped carbon (Pt / Mo2C-NC) composite catalysts. Figure 5 and Figure 6 shown.

[0036] Example 10 Compared with Example 9, in step (2), the dry platinum salt is impregnated into the Mo2C-NC carrier, and the carrier is placed in a 5% hydrogen / argon atmosphere and heat-treated at 300°C for 2h. The rest is the same as in Example 9.

[0037] Example 11 Compared with Example 9, in step (2), the dry platinum salt is impregnated into the Mo2C-NC carrier, and the carrier is placed in a 5% hydrogen / argon atmosphere and heat-treated at 400°C for 2h. The rest is the same as in Example 9.

[0038] Example 12 Compared with Example 9, in step (2), the dry platinum salt is impregnated into the Mo2C-NC carrier, and the carrier is placed in a 5% hydrogen / argon atmosphere and heat-treated at 500°C for 2h. The rest is the same as in Example 9.

[0039] Comparative Example 1 In the first impregnation step of Comparative Example 1, compared with Example 1, step (2) is omitted, and the rest are the same as Example 1; the second impregnation step is the same as Example 9, and the TEM image of the prepared catalyst is Pt-NC catalyst as shown in FIG. Figure 7 shown.

[0040] Table 2 Average Pt particle size of catalysts prepared in Examples 9 to 12

[0041] As can be seen from Table 2, during the reduction process of Pt / Mo2C-NC in a 5% hydrogen / argon atmosphere, as the treatment temperature increases (200°C-500°C), the particle size of Pt gradually increases, from 2.1 nm to 4.8 nm. The present invention found that when the temperature is too high, the nanoparticles gradually agglomerate, resulting in the growth of Pt nanoparticles. Therefore, it is necessary to select a suitable temperature during the reduction process under a hydrogen / argon atmosphere to achieve uniform dispersion of Pt nanoparticles and prevent agglomeration. In addition, for the Pt-NC catalyst in Comparative Example 1, the average nanoparticle size of Pt becomes 3.6 nm in the absence of Mo2C. In addition, by comparing the TEM photos of Example 9 (200-Pt / Mo2C-NC) Figure 6 TEM images of the comparative example (200-Pt-NC) are shown in Figure 7 , which shows that Mo2C-NC can, on the one hand, control the size of Pt nanoparticles, and on the other hand, make the Pt nanoparticles disperse more evenly and avoid serious agglomeration of nanoparticles.

[0042] The electrochemical test data of the three-electrode test system are shown in Table 3. 200-Pt / Mo2C-NC, 300-Pt / Mo2C-NC, 400-Pt / Mo2C-NC, 500-Pt / Mo2C-NC, and 200-P-NC showed good electrochemical performance at a current density of 10 mA cm -2 The corresponding overpotentials are shown in Table 3, which are 62.1, 72.4, 80.2, 86.4, and 115.2 mV respectively; the corresponding charge transfer resistances are shown in Table 3, which are 1.31, 1.46, 1.61, 1.75, and 2.14 Ω respectively; the corresponding stability / performance retention rates are shown in Table 3, which are 96.1%, 93.2%, 91.2%, 90.6%, and 81.2% respectively.

[0043] The 2.1 nm Pt (Example 9) has more active sites and a higher specific surface area, corresponding to the best HER activity (overpotential of 62.1 mV, Table 3). It also has the lowest charge transfer resistance (Rct = 1.31 Ω), with a performance retention rate of 96.1% after 2000 cycles, indicating that small particles are more conducive to electron conduction and maintain stability. In contrast, the 4.8 nm Pt (Example 12) has fewer active sites, an overpotential of 86.4 mV, and an Rct of 1.75 Ω.

[0044] 1. The overpotential of Pt / Mo2C-NC (62.1 mV) is much lower than that of Pt-NC (115.2 mV) or Mo2C-NC (usually >150 mV) alone, indicating that the introduction of Pt increases the hydrogen desorption ability of Mo2C. The lower the overpotential, the more significantly improved its hydrogen evolution reaction (HER) activity and the better the catalytic activity; the lower the charge transfer resistance, the better the interfacial electron transfer and interfacial mass transfer effects. In other words, the interfacial electron transfer between Mo2C and Pt optimizes the hydrogen adsorption / desorption energy (ΔG h * close to 0 eV); 2. The high hardness of Mo2C inhibits the sintering of Pt particles, allowing them to maintain a small particle size of 2.1 nm after reduction at 200°C (compared to the 3.6 nm particle size of Pt-NC without Mo2C); 3. Nitrogen-doped carbon enhances the metal-support bonding through the SMSI effect. Table 1 shows that the performance is best when the N content is 8.2 at%, indicating that moderate N doping can improve electronic conductivity; the three factors synergistically improve catalytic activity and durability.

[0045] Table 3 Electrochemical test data

[0046] After 2000 cycles, the performance retention rate of the catalyst prepared in Example 9 reached 96.1%, far exceeding the 81.2% of the comparative example Pt-NC, demonstrating that the Pt-Mo2C synergistic effect significantly enhanced the catalytic activity.

[0047] The present invention is not limited to the above-described embodiments. Any changes in shape or structure fall within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims. Those skilled in the art may make various changes, modifications, substitutions, combinations, and simplifications to these embodiments without departing from the principles and essence of the present invention. All such changes shall be considered equivalent replacements and fall within the scope of protection of the present invention.

Claims

1. A method for preparing a porous platinum / molybdenum carbide-nitrogen-doped carbon (Pt / Mo2C-NC) catalyst, characterized in that: The following steps are involved: (1) impregnating the pretreated porous carbon support in an aqueous solution of molybdate and ultrasonically treating the porous carbon support, and then freeze-drying the porous carbon support to obtain dry molybdate-impregnated porous carbon; (2) Grinding the molybdate-impregnated porous carbon and melamine dried in (1) at a mass ratio of molybdate-impregnated porous carbon to melamine of 1:1-1:10 until the mixture is uniformly mixed to obtain a mixed sample; (3) The mixed sample in (2) was placed in an inert gas atmosphere, calcined at high temperature, cooled to room temperature, and collected to obtain a Mo2C-NC carrier; (4) impregnating the Mo2C-NC support in (3) in an aqueous solution of a platinum group noble metal salt and ultrasonically treating the support, and then freeze-drying the support to obtain a dry platinum salt-impregnated Mo2C-NC support; (5) The platinum salt-impregnated Mo2C-NC carrier dried in (4) was placed in a 5% hydrogen / argon atmosphere, heat treated at 200-500°C for 2 h, and then cooled to room temperature to obtain a porous platinum / molybdenum carbide-nitrogen-doped carbon (Pt / Mo2C-NC) composite catalyst.

2. The preparation method according to claim 1, characterized in that In step (1), the method for treating the pretreated porous carbon support is as follows: heat-treating the porous carbon support at 800° C. for 2 h under the protection of an inert gas to remove surface impurities and adsorbed water, thereby obtaining a pretreated porous carbon support; The porous carbon is biomass carbon or commercial activated carbon, and has a specific surface area of ​​≥500 m² / g.

3. The preparation method according to claim 1, characterized in that In step (1), the molybdate is a combination of one or more of ammonium molybdate, ammonium dimolybdate, ammonium octamolybdate, ammonium molybdate tetrahydrate, ammonium heptamolybdate hydrate, and ammonium tetramolybdate dihydrate; The mass ratio of the molybdate to the porous carbon support is 1:3-5.

4. The preparation method according to claim 1, characterized in that In step (1), the specific method of ultrasonic treatment and freeze drying is as follows: the impregnated carbon support is ultrasonicated in an ultrasonic device for 1 hour, and then placed in a freeze dryer, with a pre-freezing temperature of -50°C, a pre-freezing time of 3 hours, a vacuum degree of 20 Pa, and a drying time of 24 hours; The ultrasonic conditions are as follows: temperature: 25°C, power: 150 W, frequency: 25 kHz.

5. The preparation method according to claim 1, characterized in that In step (2), the grinding is mechanical grinding, and a ball mill or an agate mortar is used for mechanical grinding.

6. The preparation method according to claim 1, characterized in that In step (3), the high temperature calcination conditions are: calcination temperature 600-900°C, time is 2 h.

7. The preparation method according to claim 1, characterized in that In step (4), the platinum group metal source in the platinum group noble metal salt includes: dichloride, trichloride, tetrachloride, and nitrate of ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), and platinum (Pt). Or a hydrochloric acid tetrachloride hydrate containing a platinum group metal element: such as one or a combination of chloroplatinic acid, chloroiridic acid, and chlororhodic acid; The platinum group metal loading in the platinum group noble metal salt is 5-20 wt%, preferably 10 wt%; The competitive adsorbent introduced into the aqueous solution of the platinum group metal salt includes one or more combinations of methanol, ethanol, ethylene glycol, isopropanol, citric acid, tartaric acid, lactic acid, oxalic acid, formic acid, acetic acid, trichloroacetic acid, hydrochloric acid, polyethylene glycol, hexadecyl ammonium chloride, sodium dodecylbenzenesulfonate, etc.

8. The preparation method according to claim 1, characterized in that In step (4), the specific method of ultrasonic treatment and freeze drying is as follows: the impregnated carbon support is ultrasonicated in an ultrasonic device for 1 hour, and then placed in a freeze dryer, with a pre-freezing temperature of -50°C, a pre-freezing time of 3 hours, a vacuum degree of 20 Pa, and a drying time of 24 hours; The ultrasonic conditions are as follows: temperature: 25°C, power: 150 W, frequency: 25 kHz.

9. A porous platinum / molybdenum carbide-nitrogen-doped carbon (Pt / Mo2C-NC) catalyst, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8, the Mo2C in the catalyst has a particle size of 2-5 nm.

10. Use of the porous platinum / molybdenum carbide-nitrogen-doped carbon (Pt / Mo2C-NC) catalyst according to claim 9 in hydrogen production by water electrolysis.

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