Method for preparing pt nanoparticle-mo2c supported pt single-atom electrocatalyst by carbon nanocage ortho double confinement pyrolysis path and application thereof

Abstract

The application aims to provide a method for preparing a Pt nanoparticle-Mo2C supported Pt single-atom electrocatalyst through carbon nanocage ortho birestricted pyrolysis path and application thereof, and belongs to the technical field of electrocatalysis.The method is prepared through a one-step double-restriction pyrolysis strategy.Under the spatial restriction of carbon nanocage, Pt single atoms are precisely restricted by Mo2C, and Pt nanoparticles are stably distributed in the vicinity of the Pt single atoms restricted by Mo2C, forming a nanoparticle-single atom ortho biregion synergistic catalytic structure.The design not only adsorbs OH and H intermediates on different sites, breaking through the linear scale limitation of a single site, but also effectively promotes the desorption and overflow of OH by introducing Mo2C as an "OH relay rod", overcoming the problems of OH blockage and slow kinetics in traditional nanometer metal particle and single-atom catalysts.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology, specifically relating to a method for preparing Pt nanoparticle-Mo2C supported Pt single-atom electrocatalysts via a carbon nanocage ortho-confined pyrolysis pathway and its application. Background Technology

[0002] Alkaline anion exchange membrane electrolysis (AEMWE) technology combines the high efficiency of proton exchange membrane electrolysis with the low cost of alkaline electrolysis, making it a highly promising green hydrogen production route. However, this technology faces a key scientific challenge in alkaline environments: the slow kinetics of the hydrogen evolution reaction (HER) severely restricts its energy efficiency and large-scale application potential. This bottleneck stems from the high energy barrier of the water dissociation steps involved in the alkaline HER process, and the fact that its intermediate products... OH and reaction intermediate H Competitive adsorption tends to occur at the same active site, significantly slowing down the reaction process. In recent years, researchers have attempted to improve hydrogen evolution performance using advanced materials such as nanomaterials and single-atom catalysts (NMP-SACs), but these strategies often struggle to precisely control key intermediates. The desorption behavior of OH causes the active site to be... The strong adsorption of OH molecules causes "blockage," leading to a rapid decline in catalytic activity. Summary of the Invention

[0003] This invention addresses the existing problems associated with nano-metal particles and single-atom catalysts. To address the problems of OH active site aggregation, blockage, poor stability, and complex preparation processes, a novel ortho-confined pyrolysis strategy for carbon nanocages is proposed, which involves the precise construction of Pt... n -Pt1@Mo2C / NPC ortho-dual-site catalyst, with Mo2C introduced as an "OH- relay baton" to promote OH overflow to further accelerate OH desorption, achieving OH and H Highly efficient separation and adsorption Rapid OH desorption significantly improves the performance and stability of alkaline HER.

[0004] This invention proposes an "OH- relay" effect. Molybdenum carbide (Mo2C), acting as the proposed "OH- relay," is introduced into the platinum nanoparticle-platinum single-atom ortho-position composite catalyst (Pt). n In the structure of Pt1, Mo2C plays an ideal "OH- relay" role: on the one hand, it can effectively anchor and stabilize Pt1 single atoms, preventing their aggregation and deactivation; on the other hand, it can preferentially adsorb and rapidly transfer Pt1 sites. OH species, thus overcoming the Pt1 site Overcoming the OH blockage challenge significantly accelerated the kinetics of the water dissociation process. A novel Pt structure was successfully synthesized using a "one-step double-constrained pyrolysis" synthesis strategy. n -Pt1@Mo2C / NPC composite catalyst. This catalyst exhibits excellent overall performance in AEMWE devices, achieving not only a lower cell operating voltage but also excellent long-term operational durability. This invention not only provides a novel solution for overcoming the performance bottleneck of alkaline HER catalysts but also opens up new avenues for designing highly efficient dual-site synergistic catalytic systems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing Pt nanoparticle-Mo2C supported Pt single-atom electrocatalyst via a carbon nanocage ortho-site dual-confined pyrolysis pathway includes the following steps: S1. Preparation of nitrogen-doped porous carbon NPC After grinding ZIF-8 powder, it was placed in an alumina boat and then placed in a tube furnace for calcination. Under an argon atmosphere, the temperature was raised to 800-1000 ℃ at a rate of 5-10 ℃ / min and calcined at this temperature for 3-5 h. After it was naturally cooled to room temperature, the collected black powder was nitrogen-doped porous carbon NPC. S2, Precursor Pt1-Pt1@PMo 12 / NPC Preparation a. NPCs and PMo 12 Dispersed in deionized water, stirred at 25°C for 4 h, filtered, washed with deionized water, and vacuum dried at 60°C overnight to obtain PMo. 12 / NPC; b. PMo 12 The NPC sample was dispersed in deionized water and sonicated for 20 minutes to form a homogeneous suspension. Under continuous stirring, an aqueous solution of chloroplatinic acid hexahydrate was slowly added dropwise, and the mixture was magnetically stirred in a 60°C water bath for 16-17.5 hours. After the reaction was complete, the mixture was centrifuged at 10,000 rpm for 15 minutes to collect the precipitate. The precipitate was washed 3-4 times with deionized water and finally vacuum-dried overnight at 60°C to obtain the dual-confined precursor Pt1-Pt1@PMo. 12 / NPC; S3, Pt carbon nanocage ortho-confined pyrolysis catalyst n Preparation of -Pt1@Mo2C / NPC Pt1-Pt1@PMo 12The NPC was placed in an alumina boat and then placed in a tube furnace. Under a mixed atmosphere of H2 / Ar, the temperature was increased to 800-1000℃ at a rate of 2-10℃ / min, and calcined at this temperature for 2-4 hours. After natural cooling, the target catalyst Pt was obtained. n -Pt1@Mo2C / NPC.

[0006] Furthermore, the mass of the ZIF-8 powder mentioned in S1 is 5-10g.

[0007] Furthermore, in step S2a, the NPC and PMo 12 The ratio of the amount of water used to deionized water is 25-35mg: 35-45mg: 10mL.

[0008] Further, in step S2b, the PMo 12 The ratio of NPC, deionized water, and chloroplatinic acid hexahydrate aqueous solution is 25-40 mg: 10 mL: 280-350 μL; the concentration of the chloroplatinic acid hexahydrate aqueous solution is 0.02 g / mL.

[0009] Furthermore, in S3, the volume ratio of H2 in the H2 / Ar mixed atmosphere is 5-10%.

[0010] Pt nanoparticle-Mo2C supported Pt single-atom electrocatalysts are used in alkaline water electrolysis for hydrogen evolution reaction, as well as in three-electrode systems or alkaline anion exchange membrane electrolyzers.

[0011] The principle of this invention is as follows: The so-called "double confinement" refers to the simultaneous confinement of a single Pt atom (Pt1) by phosphomolybdic acid (PMo). 12 The oxygen quadruple vacancy (O4H) and the N cavity confinement in nitrogen-doped porous carbon (NPC), where PMo 12 Pt1 is anchored via the Pt-O bond, and the NPC stabilizes Pt1 via the Pt-N bond, which is controlled by PMo. 12 The first confinement layer is formed by O4H, and the second confinement layer is formed by nitrogen cavities in NPC, resulting in a double confinement effect. After pyrolysis, PMo 12 Converted to Mo2C, and finally Pt is constructed. n Ortho-site dual-site catalyst in which Pt nanoparticles coexist with Pt1@Mo2C (Pt single atoms confined in Mo2C).

[0012] Specifically as follows: 1. Support design: Nitrogen-doped porous carbon (NPC) derived from ZIF-8 is used as the support. It inherits the rhombic dodecahedral nanocage structure of ZIF-8 (pore size ~1 nm) and is rich in N active sites, which can anchor Pt single atoms through Pt-N bonds. 2. Dual-confined precursor design: The first confinement layer consists of phosphomolybdic acid (PMo). 12 ) Achieve - PMo 12 The molecule (0.75–0.8 nm in size) is confined within an NPC nanocage. Its oxygen quadruple vacancy (O₄H) provides secondary confinement of the Pt single atom via Pt-O bonds. The second confinement is achieved by the N-cavity of the NPC, which stabilizes the Pt single atom through Pt-N bonds, forming Pt₁–Pt₁@PMo. 12 / NPC precursor; 3. Pyrolysis Conversion: The precursor is pyrolyzed in a mixed H2 / Ar atmosphere to produce PMo. 12 Reduced to Mo2C, some Pt ​​single atoms aggregate in situ to form Pt nanoparticles (Pt). n ), ultimately yielding Pt n Two-site catalysts (Pt1@Mo2C) coexisting with Pt1 confined in Mo2C (Pt1@Mo2C) n -Pt1@Mo2C / NPC). Mo2C acts as the "OH- relay baton," utilizing its strong affinity for oxygen to bind the Pt1@Mo2C surface... OH is transferred quickly, avoiding OH blockage; Pt n Dominant H Adsorption and desorption: Pt1@Mo2C is responsible for the dissociation of water molecules, and the two work together to accelerate HER kinetics.

[0013] The beneficial effects of this invention are as follows: 1. This invention constructs a unique ortho-dual-site synergistic catalytic structure: using the aforementioned preparation method, an ortho-dual-site composite structure in which Pt nanoparticles and Pt single atoms supported on Mo2C coexist within a carbon nanocage was successfully constructed. This structure enables the reaction intermediate... OH and H The separate adsorption and synergistic effect at different active sites solve the problem of "single-site adsorption competition," and further promotes adsorption through the strong oxygen affinity of Mo2C. The desorption and overflow of OH intermediates breaks through the limitation of the adsorption energy of reaction intermediates at a single site in the traditional method, thus optimizing the reaction pathway.

[0014] 2. Improved HER reaction kinetics and stability: The Mo2C component in the catalyst material can efficiently promote... The desorption of the OH intermediate significantly accelerates the kinetics of the basic hydrogen evolution reaction (HER). Simultaneously, this stable carbon-based confined structure effectively prevents the migration and aggregation of active sites during the reaction, endowing the catalyst with excellent durability.

[0015] 3. Achieved efficient utilization of precious metals: While maintaining high activity, the catalyst significantly reduced the total loading of precious metal Pt, and by constructing a synergistic system of Pt single atoms and nanoparticles, it fully enhanced the intrinsic activity of each Pt atom, providing a new approach for designing low-cost, high-performance electrocatalysts. Attached Figure Description

[0016] Figure 1 Pt prepared in Example 1 n TEM image of the Pt1@Mo2C / NPC catalyst; Figure 2 Pt prepared in Example 1 n HAADF-STEM image of Pt@Mo2C / NPC catalyst; Figure 3 Mo2C-free catalyst Pt prepared for Comparative Example 1 n TEM image of -Pt1 / NPC; Figure 4 Mo2C-free catalyst Pt prepared for Comparative Example 1 n HAADF-STEM image of -Pt1 / NPC; Figure 5 For Pt n -Pt1@Mo2C / NPC, Pt n -Polarization curves of three catalyst materials: Pt1 / NPC and Pt / C; Figure 6 For Pt n -Pt1@Mo2C / NPC、Pt n Tafel curves for Pt1 / NPC and Pt / C materials; Figure 7 Pt prepared in Example 1 n -Pt1@Mo2C / NPC catalyst and Mo2C-free catalyst Pt prepared in Comparative Example 1 n -Pt1 / NPC and commercial Pt / C at different scan rates (10-120 mV s) -1 CV curve under ) Figure 8 Pt prepared in Example 1 n -Pt1@Mo2C / NPC catalyst and the Mo2C-free catalyst Pt prepared in Comparative Example 1 n Polarization curves of Pt1 / NPC before and after 10,000 CV cycles; Figure 9 Pt prepared according to Example 1 nLSV curves of Pt1@Mo2C / NPC catalyst and commercial Pt / C as cathode electrode and NiFeLDH as anode; Figure 10 Pt prepared in Example 1 n -Pt1@Mo2C / NPC catalyst as cathode electrode, NiFeLDH as anode, at 60℃, 1 A cm⁻¹ -2 Stability test of AEM electrolyzer under current density. Detailed Implementation

[0017] The following embodiments are merely preferred technical solutions of the present invention and are not intended to limit the present invention in any way. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0018] Example 1 A method for preparing Pt nanoparticle-Mo2C supported Pt single-atom electrocatalysts via a carbon nanocage ortho-site dual-confined pyrolysis pathway is described below: (1) Place 8 g of ground ZIF-8 powder in a tube furnace, raise the temperature to 1000°C at a rate of 5°C / min under an Ar atmosphere, calcine at a constant temperature for 3 h, and obtain the precursor NPC after natural cooling. (2) Mix 25 mg NPC and 40 mg PMo 12 Dispersed in 10 mL of deionized water, stirred at 25 °C for 4 h, filtered, and dried under vacuum at 60 °C to obtain PMo. 12 / NPC; 25 mg PMo 12 / NPC was dispersed in 10 mL of deionized water and sonicated for 20 min to form a suspension; 280 μL of 0.02 g / mL chloroplatinic acid hexahydrate aqueous solution was slowly added, and the mixture was stirred in a water bath at 60 °C for 17.5 h. The precipitate was collected by centrifugation and dried under vacuum at 60 °C overnight to obtain the dual-confined precursor Pt1-Pt1@PMo. 12 / NPC; (3) Pt n Preparation of -Pt1@Mo2C / NPC: Pt1-Pt1@PMo 12 The NPC was placed in an alumina boat and then placed in a tube furnace. Under a 5% H2 / Ar mixed atmosphere, the temperature was increased to 900℃ at a heating rate of 2℃ / min, and calcined at this temperature for 3 h. After natural cooling, the target catalyst Pt was obtained. n -Pt1@ Mo2C / NPC.

[0019] Figure 1 Pt prepared in Example 1 nTEM image of the Pt1@Mo2C / NPC catalyst. (Source: [Insert Source Name here]) Figure 1 As can be seen from the pyrolysis, the material still retains the rhombic dodecahedral morphology of the MOF precursor, and the nanoparticles are relatively uniformly distributed. However, some larger particles appeared in some edge regions, which may be due to the fact that atoms at the substrate edge are more likely to agglomerate during pyrolysis. Further magnified observation ( Figure 1 (b) It was found that most of the particles were evenly dispersed.

[0020] Figure 2 Pt prepared in Example 1 n HAADF-STEM image of the Pt1@Mo2C / NPC catalyst. Figure 2 a indicates that Pt n The nanoparticles in -Pt1@Mo2C / NPC exhibit higher uniformity and display an alternating light and dark distribution pattern. Figure 2 The brighter particles in b correspond to Pt. n The darker areas are Mo2C clusters or particles. Notably, one or more bright spots were observed within the Mo2C clusters / particles, indicating that Pt was successfully loaded onto the Mo2C surface in single-atom form. To more precisely confirm this conclusion, Figure 2 c and d show HADDF-STEM images with clear lattice fringes. The exposed particle lattice spacings in the images are 0.198 nm and 0.118 nm, respectively, corresponding to Pt n The (200) and (311) crystal planes. In addition, the low crystallinity of Mo2C may be due to the lattice distortion caused by the incorporation of Pt1.

[0021] Comparative Example 1 Pt without introducing Mo2C component as "OH- relay bar" n Synthesis of Pt1 / NPC catalyst: (1) Place 8 g of ground ZIF-8 powder in a tube furnace and heat it to 1000 °C at a heating rate of 5 °C / min under an Ar atmosphere. Calcinate at a constant temperature for 3 h and then cool naturally to obtain the precursor NPC. (2) Add 280 µL of hydrated chloroplatinic acid aqueous solution (0.02 g / mL) and 10 mL of deionized water to 25 mg NPC, and then stir continuously for 17.5 h in a water bath at 60 ℃. Then collect the precipitate by centrifugation, wash it with deionized water 3-4 times, and dry it overnight in a vacuum oven at 60 ℃ to obtain Pt1 / NPC; (3) Place Pt1 / NPC in an alumina boat, and then place it in a tube furnace and calcine at 400 °C for 2 h in a 5% H2 / Ar atmosphere (heating rate is 2 °C / min).-1 Pt was prepared. n -Pt1 / NPC.

[0022] Figure 3 Mo2C-free catalyst Pt prepared for Comparative Example 1 n -TEM image of Pt1 / NPC, the image shows Pt n -Pt1 / NPC retains the original morphology of ZIF-8 and has a relatively uniform particle distribution, which is conducive to the rapid transport of protons / electrons.

[0023] Figure 4 Mo2C-free catalyst Pt prepared for Comparative Example 1 n Low and high resolution HAADF-STEM images of Pt1 / NPC show that Pt exhibits a uniformly dispersed particle morphology, ensuring the durability of the catalyst.

[0024] Example 2 (1) Place 5 g of ground ZIF-8 powder in a tube furnace, raise the temperature to 800°C at a rate of 10°C / min under an Ar atmosphere, calcine at a constant temperature for 5 h, and obtain the precursor NPC after natural cooling. (2) Mix 30 mg NPC and 35 mg PMo 12 Dispersed in 10 mL DI, stirred at 25 °C for 4 h, filtered, and dried under vacuum at 60 °C to obtain PMo. 12 / NPC; 25 mg of PMo 12 / NPC was dispersed in 10 mL of deionized water and sonicated for 20 min to form a suspension; 300 μL of 0.02 g / mL chloroplatinic acid hexahydrate aqueous solution was slowly added, and the mixture was stirred in a water bath at 60 °C for 16 h. The precipitate was collected by centrifugation and dried under vacuum at 60 °C overnight to obtain the dual-confined precursor Pt1-Pt1@PMo. 12 / NPC; (3) Pt1-Pt1@PMo 12 The NPC was placed in an alumina boat and then placed in a tube furnace. Under a 5% H2 / Ar mixed atmosphere, the temperature was increased to 800℃ at a heating rate of 5℃ / min, and calcined at this temperature for 2 h. After natural cooling, the target catalyst Pt was obtained. n -Pt1@Mo2C / NPC.

[0025] Example 3 (1) Place 10 g of ground ZIF-8 powder in a tube furnace, raise the temperature to 900 °C at a rate of 15 °C / min under an Ar atmosphere, calcine at a constant temperature for 5 h, and obtain the precursor NPC after natural cooling. (2) Mix 35 mg NPC and 45 mg PMo 12Dispersed in 10 mL DI, stirred at 25 °C for 4 h, filtered, and dried under vacuum at 60 °C to obtain PMo. 12 / NPC; 25 mg of PMo 12 / NPC was dispersed in 10 mL of deionized water and sonicated for 20 min to form a suspension; 350 μL of 0.02 g / mL chloroplatinic acid hexahydrate aqueous solution was slowly added, and the mixture was stirred in a water bath at 60 °C for 17 h. The precipitate was collected by centrifugation and dried under vacuum at 60 °C overnight to obtain the dual-confined precursor Pt1-Pt1@PMo. 12 / NPC; (3) Pt1-Pt1@PMo 12 The NPC was placed in an alumina boat and then placed in a tube furnace. Under a 10% H2 / Ar mixed atmosphere, the temperature was increased to 1000℃ at a heating rate of 10℃ / min, and calcined at this temperature for 4 h. After natural cooling, the target catalyst Pt was obtained. n -Pt1@Mo2C / NPC.

[0026] Figure 5 To test the electrocatalytic HER performance of the catalyst materials prepared in Example 1 and Comparative Example 1 in 1 M KOH solution, a standard three-electrode system was used to evaluate the performance of commercial Pt / C and Pt catalysts. n -Pt1 / NPC and Pt1-Pt1@PMo 12 The HER performance of / NPC in 1.0 M KOH solution was systematically evaluated (all potentials were iR-compensated and referenced to RHE), with LSV measurements ranging from -0.80 to -1.2 V vs. Hg / HgO (0.075 to -1.2 V vs. Hg / HgO) at a scan rate of 50 mV s. -1 As shown in the polarization curve in the figure, the current density is 10 mA cm⁻¹. -2 When (η10), Pt n -Pt1@Mo2C / NPC exhibits an ultra-low overpotential of 24 mV, significantly outperforming commercial Pt / C (35 mV) and Pt n -Pt1 / NPC (65 mV).

[0027] Figure 6 The Tafel curves calculated based on LSV curves are shown (the Tafel slope is determined by plotting the logarithm of current density versus overpotential (log |j|)). The Tafel slope of the linear portion can be used for preliminary evaluation of the catalyst's activity in the hydrogen evolution reaction. A smaller Tafel slope indicates a rapid increase in current density, implying faster reaction kinetics and higher catalytic activity. Pt n The Tafel slope of -Pt1@Mo2C / NPC is 30.9 mV dec.-1 It is far lower than that of Pt without the introduction of Mo2C component. n -Pt1 / NPC (101.2 mV dec) -1 This indicates that it achieves a larger current density and a faster hydrogen evolution rate at a lower potential, demonstrating that the introduction of Mo2C can significantly enhance water dissociation kinetics.

[0028] Figure 7 Pt prepared in Example 1 n -Pt1@Mo2C / NPC catalyst and the Mo2C-free catalyst Pt prepared in Comparative Example 1 n -Pt1 / NPC and commercial Pt / C under non-Radidatic potential windows, at different scan rates (10-120 mV s) -1 The CV curve obtained from the CV test under ( ) is shown in the figure. Compared to Pt n -Pt1 / NPC, Pt n -Pt1@Mo2C / NPC exhibits the highest current density at 0.3–0.4 V (vs. RHE), indicating that it has higher electrocatalytic activity.

[0029] Figure 8 Pt prepared in Example 1 n Polarization curves of Pt1@Mo2C / NPC catalyst before and after 10,000 CV cycles. In 1 MkOH solution, Pt... n -Pt1@Mo2C / NPC and Pt n -Pt1 / NPC underwent 10,000 CV cycle tests. A comparison of the LSV curves before and after the cycle shows that Pt... n -Pt1@Mo2C / NPC at 10 mAcm -2 The polarization curve at the current density of Pt shows only a negligible shift, while Pt n The large offset of the Pt1 / NPC curve further proves that Pt n -Pt1@Mo2C / NPC compared to Pt n -Pt1 / NPC maintains long-term catalytic stability even in harsh alkaline environments.

[0030] Further, a Pt-based system was built in AEMWEs. n A membrane electrode assembly with Pt1@Mo2C / NPC as the cathode was used to evaluate its performance in practical water dissociation. Specifically, Pt1@Mo2C / NPC was used as the cathode. n - An AEM electrolyzer was formed by sandwiching Pt1@Mo2C / NPC and a commercially available Pt / C catalyst as the cathode and a self-made NiFeLDH catalyst as the anode on the membrane. Pt was then tested. n -Pt 1@Mo2C / NPC alkaline HER performance in AEM reactor.

[0031] Figure 9 Pt prepared according to Example 1 n LSV curves of Pt1@Mo2C / NPC commercial Pt / C catalyst as cathode and NiFeLDH as anode. The figure shows that at the same cell potential, Pt... n -Pt1@Mo2C / NPC has a higher current density than commercial Pt / C, therefore Pt n -Pt1@Mo2C / NPC demonstrates significant advantages in terms of economic cost and scalability.

[0032] Figure 10 Pt prepared in Example 1 n -Pt1@Mo2C / NPC catalyst as cathode electrode, NiFeLDH as anode, at 60℃, 1 A cm⁻¹ -2 Stability test of AEM electrolyzer under current density. The figure shows Pt... n -Pt1@Mo2C / NPC exhibits good long-term stability, with negligible potential fluctuations after 120 hours of IT testing, indicating that Pt n -Pt1@Mo2C / NPC has great potential in alkaline HER industrial applications.

[0033] The above embodiments are only used to illustrate the content of the present invention, but they are not intended to limit the present invention. Those skilled in the art can make corresponding adjustments and modifications without departing from the scope of the present invention. Therefore, all technical solutions formed by equivalent substitutions or equivalent modifications are within the protection scope of the present invention.

Claims

1. A method for preparing Pt nanoparticle-Mo2C supported Pt single-atom electrocatalysts via a carbon nanocage ortho-confined pyrolysis pathway, characterized in that: Includes the following steps: S1. Preparation of nitrogen-doped porous carbon NPC After grinding ZIF-8 powder, it was placed in an alumina boat and then placed in a tube furnace for calcination. Under an argon atmosphere, the temperature was raised to 800-1000 ℃ at a rate of 5-10 ℃ / min and calcined at this temperature for 3-5 h. After it was naturally cooled to room temperature, the collected black powder was nitrogen-doped porous carbon NPC. S2, Precursor Pt1-Pt1@PMo 12 / NPC Preparation a. NPCs and PMo 12 Dispersed in deionized water, stirred at 25°C for 4 h, filtered, washed with deionized water, and vacuum dried at 60°C overnight to obtain PMo. 12 / NPC; b. PMo 12 The NPC sample was dispersed in deionized water and sonicated for 20 minutes to form a homogeneous suspension. Under continuous stirring, an aqueous solution of chloroplatinic acid hexahydrate was slowly added dropwise, and the mixture was magnetically stirred in a 60°C water bath for 16-17.5 hours. After the reaction was complete, the mixture was centrifuged at 10,000 rpm for 15 minutes to collect the precipitate. The precipitate was washed 3-4 times with deionized water and finally vacuum-dried overnight at 60°C to obtain the dual-confined precursor Pt1-Pt1@PMo. 12 / NPC; S3, Pt carbon nanocage ortho-confined pyrolysis catalyst n Preparation of -Pt1@Mo2C / NPC Pt1-Pt1@PMo 12 The NPC was placed in an alumina boat and then placed in a tube furnace. Under a mixed atmosphere of H2 / Ar, the temperature was increased to 800-1000℃ at a rate of 2-10℃ / min, and calcined at this temperature for 2-4 hours. After natural cooling, the target catalyst Pt was obtained. n -Pt1@Mo2C / NPC.

2. The method for preparing Pt nanoparticle-Mo2C supported Pt single-atom electrocatalyst via a carbon nanocage ortho-confined pyrolysis pathway according to claim 1, characterized in that: The mass of the ZIF-8 powder mentioned in S1 is 5-10g.

3. The method for preparing Pt nanoparticle-Mo2C supported Pt single-atom electrocatalyst via a carbon nanocage ortho-confined pyrolysis pathway according to claim 1, characterized in that: In step S2a, the NPC and PMo 12 The ratio of the amount of water used to deionized water is 25-35mg: 35-45mg: 10mL.

4. The method for preparing Pt nanoparticle-Mo2C supported Pt single-atom electrocatalyst via a carbon nanocage ortho-confined pyrolysis pathway according to claim 1, characterized in that: In step S2b, the PMo 12 The ratio of NPC, deionized water, and chloroplatinic acid hexahydrate aqueous solution is 25-40 mg: 10 mL: 280-350 μL; the concentration of the chloroplatinic acid hexahydrate aqueous solution is 0.02 g / mL.

5. The method for preparing Pt nanoparticle-Mo2C supported Pt single-atom electrocatalyst via a carbon nanocage ortho-confined pyrolysis pathway according to claim 1, characterized in that: In S3, the volume ratio of H2 in the H2 / Ar mixed atmosphere is 5-10%.

6. A Pt nanoparticle-Mo2C supported Pt single-atom electrocatalyst prepared by the preparation method as described in claim 1 is applied to alkaline water electrolysis for hydrogen evolution reaction and in a three-electrode system or an alkaline anion exchange membrane electrolyzer.

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