Method for controlling embedding depth of in-situ grown metal phosphide nano-particles on carbon fibers and application of in-situ grown metal phosphide nano-particles in field of electro-catalytic water decomposition

Abstract

The invention relates to the technical field of electrochemical hydrogen production, and provides a method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers, the carbon fibers and application. The invention provides a bidirectional phosphating process for preparing an adjustable carbon fiber felt embedded with metal phosphide nanoparticles. The embedding depth of the metal phosphide nanoparticles on the surface of carbon fibers can be controlled. The proper embedding depth not only can ensure firm combination of the metal particles and the carbon substrate, but also can expose sufficient active sites for catalysis.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical hydrogen production, and in particular to a method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers and its application in the field of electrocatalytic water decomposition. Background Art

[0002] Carbon materials are considered to have the most promising development potential due to their good electrical conductivity and unique designability. In recent years, the research on various types of catalysts based on carbon materials has stagnated and gradually deviated from the mainstream. There are two main reasons why such materials are difficult to obtain high catalytic activity and stability: (1) In the alkaline hydrogen evolution state, a large number of bubbles appear on the electrode surface at the same time. At this time, the bubble precipitation driven by convective mass transfer is dominant. At this time, the bubbles often cannot be immediately separated and a bubble layer will form on the electrode surface, covering the active sites. Studies have shown that the energy conversion loss caused by bubble interference can account for one-third of the total energy loss in water electrolysis, significantly affecting the catalytic activity; (2) Most catalysts that use carbon as a carrier to load active substances are in powder form, such as commercial Pt / C, and need to be adhered to the electrode with an adhesive. During the long-term water decomposition process, the high-flux electron transfer at the interface between the catalyst and the electrolyte and the high-frequency liquid flow impact caused by the precipitation of a large number of bubbles will cause the adhesive to fail quickly, limiting its service life. Summary of the Invention

[0003] The present invention aims to solve at least one of the above technical problems by providing a method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers and its application in the field of electrocatalytic water splitting. The technical solutions proposed by the present invention are as follows:

[0004] The first aspect of the present invention provides a method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers, comprising the following steps:

[0005] S1, preparing an initial polyacrylonitrile (PAN) fiber felt containing a metal source CoCl2 and a phosphorus source phytic acid by electrospinning;

[0006] S2, placing the initial PAN fiber felt in a blast drying oven for pre-oxidation to obtain a pre-oxidized fiber felt;

[0007] S3. Placing a pre-oxidized fiber mat in a tube furnace, placing a pre-oxidized fiber mat to which phytic acid is added upstream of the pre-oxidized fiber mat as a pre-phosphorus source, and controlling the embedding depth of the metal phosphide particles in the carbon fibers by simultaneously regulating the amount of the pre-phosphorus source and the phytic acid content incorporated into the initial PAN fiber mat;

[0008] S4. In a reducing protective gas atmosphere, the temperature is raised to 700-1100° C. and kept at this temperature for 1-4 hours to perform bidirectional phosphating-carbonizing to obtain a carbon fiber felt embedded with metal phosphide nanoparticles.

[0009] This paper proposes a method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers. The appropriate embedding depth ensures a strong bond between the metal phosphide nanoparticles and the carbon substrate while exposing sufficient active sites for catalysis.

[0010] Preferably, in step S1, the raw materials for preparing the carbon fibers embedded with metal phosphide particles include PAN, phytic acid solution and anhydrous CoCl2.

[0011] Preferably, in step S1, the electrospinning method is to add a solvent to the initial PAN fiber felt raw material containing a metal source (CoCl2) and a phosphorus source (phytic acid) to prepare a spinning solution, and then apply a high voltage electric field to perform electrospinning.

[0012] Preferably, in step S2, the pre-oxidation is performed by heating the temperature to 250-260° C. and keeping the temperature for 1-4 hours using a gradient heating method.

[0013] Preferably, in step S3, the reducing protective gas atmosphere is a H2 / Ar mixed gas, and the volume proportion of H2 in the mixed gas is 3-25%. Preferably, in step S4, the gas flow rate of the reducing protective gas atmosphere is 10-30 mL min -1 .

[0014] Preferably, in step S4, the heating rate is 2-10°C min -1 .

[0015] A second aspect of the present invention provides a carbon fiber felt embedded with metal phosphide nanoparticles, which is prepared according to any of the above control methods.

[0016] The third aspect of the present invention provides a use of carbon fiber felt embedded with metal phosphide nanoparticles in an electrode material.

[0017] A fourth aspect of the present invention provides an application of an electrode material comprising carbon fibers embedded with metal phosphide nanoparticles in electrochemical water decomposition to produce hydrogen.

[0018] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0019] The bidirectional phosphating process provided by this invention allows for controlled embedding depth of metal phosphide nanoparticles generated in situ during the high-temperature phosphating-carbonization process into the carbon fibers by adjusting the ratio of the pre-added phosphorus source to the phosphorus content of the initial PAN fiber mat. Proper embedding of the active nanoparticles ensures a stable state during the intense catalytic gassing reaction while also exposing more active sites, thereby achieving both excellent activity and stability.

[0020] The present invention uses a unique bidirectional phosphating strategy to regulate the embedding depth of metal phosphide nanoparticles on carbon fibers, thereby achieving simultaneous improvement in catalytic performance and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a bidirectional phosphating-carbonizing process according to a preferred embodiment of the present invention;

[0022] Figure 2 SEM images of PAN fiber mats with different compositions: (a) Unstretched Co2P 1.5 @CNF; after stretching (b)-(f): (b) Co2P0 0 @ACNF, (c)Co2P 0.5 @ACNF; (d)Co2P1@ACNF; (e)Co2P 1.5 @ACNF; (f) Co2P2@ACNF;

[0023] Figure 3 Co2P 0.5 @ACNF sample TEM images: (a) low-resolution TEM image; (b) high-resolution TEM (HRTEM) image of Co2P particles (the inset is the lattice fringes of the Co2P (202) crystal plane); (c) HRTEM image of carbon fiber; (d, e) SAED spectra of Co2P particles; (f) elemental line scan of Co2P particles; (g) Co2P 0.5 High-angle annular dark field image (HAADF) of @ACNF and the corresponding elemental scan;

[0024] Figure 4 Bubble contact angle photos of different samples: (a) Co2P 0.5 @ACNF; (b)Co2P 1.5 @ACNF; (c)Co2P 0.5 @CNF;(d)CNF;

[0025] Figure 5 To investigate the effect of catalyst embedding depth (af) on HER electrocatalytic performance;

[0026] Figure 6 Co2P of the present invention 0.5Comparison of HER performance between ACNF and similar materials;

[0027] Figure 7 Co2P 0.5 @ACNF hydrogen production test (j 500 );

[0028] Figure 8 Co2P 0.5 @ACNF's step voltage method stability test. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] A preferred embodiment of the present invention provides a method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers, comprising the following steps:

[0031] S1. Prepare an initial PAN fiber felt containing a metal source (CoCl2) and a phosphorus source (phytic acid) by electrospinning: add the raw materials PAN of the initial PAN fiber felt, phytic acid solution and anhydrous CoCl2 into a solvent to prepare a spinning solution, and then apply a high voltage electric field for electrospinning.

[0032] S2. Pre-oxidizing the initial PAN fiber felt in a blast drying oven. The pre-oxidation step is to heat the felt to 250-260° C. and keep the temperature for 1-4 hours to obtain a pre-oxidized fiber felt.

[0033] S3. Place a pre-oxidized fiber felt in a tubular furnace, and place a pre-oxidized fiber felt with phytic acid added upstream of the pre-oxidized fiber felt as a pre-phosphorus source, and change the embedding depth of the in-situ generated metal phosphide nanoparticles on the carbon fiber by simultaneously regulating the placement amount of the pre-phosphorus source and the content of phytic acid added to the initial PAN fiber felt; wherein the initial PAN fiber containing phytic acid is obtained by electrospinning PAN, phytic acid solution, and anhydrous CoCl2 to form a spinning solution.

[0034] S4, in the reducing protective gas atmosphere of H2 / Ar mixed gas, at 2-10℃min -1 The temperature is raised to 700-1100℃ and kept at this temperature for 1-4h for bidirectional phosphating-carbonizing. The volume proportion of H2 in the mixed gas is 3-25%; the gas flow rate of the reducing protective gas atmosphere is 10-30mL min -1, obtaining carbon fibers embedded with metal phosphide nanoparticles.

[0035] This invention proposes a bidirectional phosphating process suitable for preparing carbon fiber felt electrodes loaded with metal phosphide nanoparticles via electrospinning. This process allows for controlled embedding depth of the metal phosphide nanoparticles into the carbon fibers. A suitable embedding depth ensures a secure bond between the nanoparticles and the carbon substrate while also exposing sufficient active sites for catalysis. This method produces a carbon fiber felt embedded with phosphide particles, which can be used as a cathode material for electrochemical water splitting to produce hydrogen.

[0036] The following are specific examples.

[0037] Example 1

[0038] (1) Preparation of spinning solution

[0039] 0.476g CoCl2·6H2O was dissolved in 20mL methanol, ultrasonicated at 100W for 10min, and then placed in a 130℃ forced air drying oven for 1h to obtain anhydrous CoCl2. 1g polyacrylonitrile (PAN), 0.5mL of 70wt.% phytic acid solution (PA), and anhydrous CoCl2 were mixed and dissolved in 12mL N,N-dimethylformamide (DMF) respectively. After continuous stirring for 12h, the spinning solution was obtained and recorded as Co2PA. 0.5 .

[0040] (2) Electrospun PAN fiber mat

[0041] The spinning solution was placed in a 10 mL syringe and a 21 G spinning needle was installed. The distance between the needle and the receiving roller was about 15 cm, the negative voltage was set to -2.5 kV, the positive voltage was set to +22.5 kV, and the propulsion speed was set to 0.05 mm min. -1 The drum was wrapped with an aluminum foil to collect the fibers, and the rotation speed was set to 1200 rpm. After spinning, the fiber mat was peeled off from the aluminum foil and dried in a forced air drying oven at 50°C for 4 hours.

[0042] (3) Pre-oxidation

[0043] Pre-oxidation adopts gradient temperature rising method, first at 1℃min -1 The temperature was raised to 200°C at a heating rate of 1000 ℃ and kept at 200°C and 215°C for 30 min respectively, then kept at 225°C, 235°C and 245°C for 40 min respectively, and finally raised to 255°C and kept for 60 min.

[0044] (4) Bidirectional phosphating-carbonization

[0045] like Figure 1As shown in FIG, the sample to be carbonized obtained in step (3) is placed downstream of the tube furnace, and 3 pieces of PAN fiber felts of the same size containing 0.1 mL PA (1 g PAN and 0.1 mL PA are mixed and spun) are placed about 5 cm upstream of the tube furnace as a pre-phosphorus source (gas-phase phosphorus source). H2 / Ar (H2 10%) mixed gas is used as the reducing protective gas, and the gas flow rate is set to 20 mL min -1 . At 5℃min -1 The heating rate was increased to 900 ° C and kept warm for 2 hours to obtain carbon fiber felt uniformly embedded with Co2P nanoparticles, which can be used as a cathode material for electrocatalytic water decomposition to produce hydrogen.

[0046] The amount of the pre-phosphorus source and the amount of the phosphorus source in the fiber are represented by superscripts and subscripts, respectively. The superscript after P represents the amount of the pre-phosphorus source, and the default value is 3 if there is no superscript. The subscript after P represents the amount of PA added to the fiber mat. The subscript number Co represents the ratio of the amount of P to Co. In this example, the obtained material is recorded as Co2P 0.5 @ACNF.

[0047] Example 2

[0048] The amount of PA added in step (1) was 1 mL, and the rest was the same as in Example 1. The obtained material was recorded as Co2P1@ACNF.

[0049] Example 3

[0050] The amount of PA added in step (1) was 1.5 mL, and the rest was the same as in Example 1. The obtained material was recorded as Co2P 1.5 @ACNF.

[0051] Example 4

[0052] The amount of PA added in step (1) was 2 mL, and the rest was the same as in Example 1. The obtained material was recorded as Co2P2@ACNF.

[0053] When the pre-P content remains unchanged, Figure 2 The Co2P nanoparticle positions shown in Figures (c)-(f) (corresponding to Examples 1-4) demonstrate the effectiveness of this bidirectional P-type strategy for controlling the in situ growth depth of metal phosphides on carbon fibers. Proper embedding of active nanoparticles not only ensures robust catalytic activity during intense gassing reactions but also exposes more active sites, contributing to the simultaneous achievement of excellent activity and stability.

[0054] Figure 3 Co2P obtained in Example 1 0.5 TEM image of @ACNF material. Figure 3(a) shows the embedding of Co2P nanoparticles on carbon fibers. From the figure we can also see the non-static oxide layer on the surface of the particles, confirming the viewpoint of XPS analysis. Figure 3 (b) shows the lattice fringes of the (202) crystal plane of Co2P nanoparticles. It is worth noting that the fringes in the photo are neat and the crystal plane is single, suggesting that the in situ grown Co2P particles may have a single crystal structure. Figure 3 (c) is the HRTEM image of carbon fiber. We can see obvious elastic layers distributed in the amorphous carbon, indicating the high conductivity of carbon fiber. Figure 3 (d) and (e) show the SAED spectra of Co2P particles. The lattice-like diffraction pattern indicates the single crystal structure of the particles, and the unique bright spots in the high-index region indicate the presence of certain lattice distortions. In addition, the superlattice-like pattern in the figure also indicates the unique long-range ordered crystal plane arrangement in the Co2P crystal. Figure 3 (f) and (g) show the results of elemental line scan and surface scan, respectively. It can be seen that O is abundant in the nanoparticles and N is uniformly doped in the carbon fibers.

[0055] Example 5

[0056] In step (4), 6 pieces of phosphorus source were placed in the front, and the rest was the same as in Example 1. The obtained material was recorded as Co2P 0.5 6 @ACNF.

[0057] Example 6

[0058] Step (4) Place 6 pieces of phosphorus source in front, and the rest is the same as in Example 2. The obtained material is recorded as Co2P1 6 @ACNF.

[0059] Example 7

[0060] Step (4) Place 6 pieces of phosphorus source in front, and the rest is the same as in Example 3. The obtained material is recorded as Co2P 1.5 6 @ACNF.

[0061] Example 8

[0062] Step (4) Place 6 pieces of phosphorus source in front, and the rest is the same as in Example 4. The obtained material is recorded as Co2P2 6 @ACNF.

[0063] Example 9

[0064] Step (4) Place two phosphorus sources in the front, and the rest is the same as in Example 3. The obtained material is recorded as Co2P 1.5 2 @ACNF.

[0065] Example 10

[0066] Step (4) Place 4 pieces of phosphorus source in front, and the rest is the same as in Example 3. The obtained material is recorded as Co2P 1.5 4 @ACNF.

[0067] Example 9

[0068] Step (4) Place 8 pieces of phosphorus source in front, and the rest is the same as in Example 3. The obtained material is recorded as Co2P 1.5 8 @ACNF.

[0069] Example 10

[0070] In step (3), no stretching is performed, only pre-oxidation is performed, and the rest is the same as in Example 1. The obtained material is recorded as Co2P 0.5 @CNF.

[0071] Example 11

[0072] In step (3), no stretching was performed, only pre-oxidation was performed, and the rest was the same as in Example 3. The obtained material was recorded as Co2P 1.5 @CNF.

[0073] from Figure 2 As can be seen in (a), this embodiment does not perform stretching, and the fiber orientation is low, but the embedding depth of the metal phosphide in the carbon fiber is similar to that of Example 3.

[0074] Comparative Example 1

[0075] No P source was introduced. No phytic acid was added in steps (1) and (3), and the rest was the same as in Example 1. The obtained material was recorded as Co2P0 0 @ACNF.

[0076] from Figure 2 As can be seen in (b), when no P source is introduced, Co2P0 0 The carbon fibers of the @ACNF sample are covered with many defects. This is because at high temperatures, carbon is a reducing agent for CoCl2, where CoCl2 is reduced to its elemental form, while the carbon fibers are converted into CO2 and escape.

[0077] Comparative Example 2

[0078] In step (1), phytic acid was not added. In step (4), 6 pieces of phosphorus source were placed in front. The rest was the same as in Example 1. The obtained material was recorded as Co2P0 6 @ACNF.

[0079] Comparative Example 3

[0080] Only polyacrylonitrile (PAN) was used to prepare the spinning solution for electrospinning to obtain non-oriented carbon fiber mat without catalyst loading, which was recorded as CNF.

[0081] The following are performance tests.

[0082] 1. Bubble contact angle measurement (CA)

[0083] The contact angle is the angle θ between the tangent line of the gas-liquid interface and the solid-liquid boundary line at the intersection of the gas, liquid and solid phases. e , a measure of surface wettability. The contact angle is commonly measured using profile image analysis. This method involves placing a liquid droplet on a solid sample surface, capturing an image of the droplet's profile using a microscope lens and camera, and then calculating the droplet's contact angle from the image using digital image processing and algorithms. This work employed the OCA 15EC contact angle meter manufactured by De Feil, Germany, to measure both the static and dynamic contact angles of bubbles to assess their ability to slide off the electrode.

[0084] To verify the effectiveness of the present invention in controlling bubbles, we tested the static and dynamic contact angles (CA) of bubbles of different samples. Figure 4 , Co2P 0.5 @ACNF (Example 1) exhibits superhydrophilic properties, with a bubble static CA of 153.1° and a sliding CA close to 0°. 1.5 The static CA of @ACNF (Example 3) is 145.9° and the sliding CA is 2.1°; Co2P 0.5 The static CA of @CNF (Example 10) is 142.9° and the sliding CA is 4.1°; the static CA of the non-oriented carbon fiber felt without catalyst loading (Comparative Example 3) is 134.2° and the sliding CA is 15°. From the above results, we can see that the CA of the bubble on the electrode is affected by the catalyst loading and fiber orientation. 0.5 @The bubbles on ACNF (Example 1) are very easy to slide, so it can effectively improve the separation efficiency of bubbles from the electrode.

[0085] 2. Electrochemical performance test

[0086] The electrochemical performance tests of water splitting were carried out at room temperature using an electrochemical workstation (CHI 660E, Shanghai Chenhua Instrument Co., Ltd.) and a standard three-electrode system. In this system, the self-supporting catalytic electrode was used as the working electrode, the carbon rod was used as the counter electrode, and Hg / HgO was used as the reference electrode. To facilitate comparison, all electrochemical performance tests were performed without any special gas pretreatment of the alkaline electrolyte, and all working electrode potentials were converted to reversible hydrogen electrode (RHE) potentials in 1 M KOH according to the Nernst equation: E vs.RHE =Evs.Hg / HgO +0.095+0.0591×pH

[14] It should be noted that all electrocatalytic performances were normalized according to the geometric area of ​​the electrode material. Due to the upper current limit of the workstation, the size of each electrode was controlled to 0.5 × 0.5 cm. 2 . In 1 M KOH at 2 mV s -1 The LSV polarization curves of HER were obtained at a scan rate of 1000 nm and a potential range of 0 to -2.4 V. In order to exclude the effect of solution resistance on the intrinsic catalytic activity of the catalyst, all potentials collected from the LSV polarization curves were compensated for 95% of the internal resistance (iR) according to the following equation unless otherwise specified: E corrected =E Raw -95% iR. Meanwhile, in 10 0 to 10 5 Electrochemical impedance spectroscopy (EIS) studies were performed over a frequency range of 100 nm and 100 nm. The H2 production rate was recorded by measuring the volume of gas produced every 2 min using a standard gas collection method.

[0087] Figure 5 (a)-(f) The pre-P content and the fiber P content were controlled to remain unchanged (Examples 5-9, Comparative Example 2) to explore the effect of particle embedding depth on HER performance. When the relative content of the pre-P source increased, the embedding depth of the metal phosphide particles decreased; when the relative content of the fiber phosphorus source increased, the embedding depth of the metal phosphide particles increased. The electrochemical test results show that when the content of pre-P or fiber P is low, the contact resistance and interface transfer resistance increase significantly, and the HER overpotential is the largest, indicating poor conductivity and lower active site exposure. The optimal catalytic performance we obtained is η 10 @77mV,η 1000 @300mV, the performance is significantly better than all similar materials reported ( Figure 6 ).

[0088] Figure 7 Co2P 0.5 @ACNF sample in j 500 Hydrogen production test under current density. Thanks to the full exploration of the catalytic performance by the nano effect, its production is similar to that of metal foam-based materials with more active sites. The hydrogen production curve is approximately a straight line, showing excellent hydrogen production stability. 500 After working for 10 minutes, the hydrogen production measured by the water displacement method was 16.6 mL.

[0089] Co2P was collected using the step voltage method. 0.5 @ACNF stability data. Figure 8 As shown, respectively in j 10 、j 100、j 200 and j 1000 It can be seen that at lower current density, the catalytic material is basically stable, but at high current density, it decays, which is attributed to the phase transformation and partial dissolution of Co2P.

[0090] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers, characterized in that: The following steps are involved: S1, preparing an initial polyacrylonitrile (PAN) fiber felt containing a metal source CoCl2 and a phosphorus source phytic acid by electrospinning; S2, placing the initial PAN fiber felt in a blast drying oven for pre-oxidation to obtain a pre-oxidized fiber felt; S3. Placing a pre-oxidized fiber mat in a tube furnace, placing a pre-oxidized fiber mat to which phytic acid is added upstream of the pre-oxidized fiber mat as a pre-phosphorus source, and controlling the embedding depth of the metal phosphide particles in the carbon fibers by simultaneously regulating the amount of the pre-phosphorus source and the phytic acid content incorporated into the initial PAN fiber mat; S4. In a reducing protective gas atmosphere, the temperature is raised to 700-1100° C. and kept at this temperature for 1-4 hours to perform bidirectional phosphating-carbonizing to obtain a carbon fiber felt embedded with metal phosphide nanoparticles.

2. The method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers according to claim 1, characterized in that: In step S1, the raw materials of the carbon fiber containing metal phosphide include polyacrylonitrile, phytic acid solution and anhydrous CoCl2.

3. The method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers according to claim 1, characterized in that: In step S1, the electrospinning method is to add metal source CoCl2 and phosphorus source phytic acid as raw materials into DMF solvent to prepare a spinning solution, and then apply a high voltage electric field to perform electrospinning.

4. The method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers according to claim 1, characterized in that: In step S2, the pre-oxidation is performed by heating the temperature to 250-260° C. and keeping the temperature for 1-4 hours using a gradient heating method.

5. The method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers according to claim 1, characterized in that: In step S4, the gas flow rate of the reducing protective gas atmosphere is 10-30 mL min -1 .

6. The method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers according to claim 1, characterized in that: In step S4, the reducing protective gas atmosphere is a H2 / Ar mixed gas, and the volume proportion of H2 in the mixed gas is 3-25%.

7. The method for controlling the embedding depth of in-situ grown metal phosphide nanoparticles on carbon fibers according to claim 1, characterized in that: In step S4, the heating rate is 2-10°C min -1 .

8. A carbon fiber felt embedded with metal phosphide nanoparticles, characterized in that: Prepared according to the control method according to any one of claims 1-7.

9. Use of the carbon fiber felt embedded with metal phosphide nanoparticles according to claim 8 in electrode materials.

10. Use of the electrode material of carbon fiber embedded with metal phosphide nanoparticles according to claim 9 in electrochemical water decomposition to produce hydrogen.

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