Preparation method and application of phosphorus-doped palladium-molybdenum alloy ultra-thin two-dimensional nanomaterial

Abstract

This invention discloses a method for preparing and applying phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials. The nanomaterials are prepared via a wet chemical method, exhibiting good dispersibility and a thin, curved two-dimensional structure with a lateral dimension of several hundred nanometers and a thickness of approximately 1.2 nanometers. Catalysts prepared by combining phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials with carbon are applied to the electrocatalytic oxidation of alcohols, demonstrating excellent activity and stability for various alcohols. The mass activities for the electrocatalytic oxidation of methanol, ethanol, ethylene glycol, and glycerol reach as high as 2.32 Å mg, respectively. ‑1 Pd 4.95A mg ‑1 Pd 4.06 mg ‑1 Pd 4.98A mg ‑1 Pd The phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterial catalyst disclosed in this invention can greatly reduce catalyst costs and improve electrocatalytic alcohol oxidation performance, showing promising application prospects in the field of alkaline direct alcohol fuel cells.

Description

Technical Field

[0001] This invention belongs to the field of functionalized nanomaterials technology, specifically relating to the preparation of a phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional structured nanomaterial and its application in the field of anode catalysts for direct alcohol fuel cells. Background Technology

[0002] Against the backdrop of continuously growing global energy demand and the increasingly severe environmental impact of fossil fuels, the need for clean, sustainable, and environmentally friendly alternative energy sources has become particularly urgent. Fuel cells are green energy conversion devices that directly convert chemical energy into electrical energy. Among them, alkaline direct alcohol fuel cells have attracted widespread attention from researchers both domestically and internationally due to their high energy density, modular structure, and high efficiency and environmental friendliness. Methanol, ethanol, ethylene glycol, and glycerol are commonly used anode fuels in direct alcohol fuel cells due to their wide availability, stable properties, and low toxicity. However, the slow kinetics, poor stability, and susceptibility to catalyst poisoning in the anode alcohol oxidation reaction severely hinder the development of direct alcohol fuel cells. Therefore, developing highly active and stable electrocatalytic alcohol oxidation catalysts is an urgent need for the commercial application of direct alcohol fuel cells.

[0003] Platinum and palladium-based materials are among the best-performing catalysts for alcohol oxidation, with palladium exhibiting higher abundance and superior anti-poisoning properties compared to platinum, making it a promising candidate for various applications. However, palladium still suffers from high cost and relatively low electrocatalytic activity. Reducing catalyst size to the nanoscale and controlling catalyst morphology and dimensionality to increase the number of active sites are common strategies for cost reduction. In particular, ultrathin two-dimensional nanomaterials with atomic-level thickness, due to their near 100% surface atomic density, can maximize palladium utilization and improve catalyst performance. Furthermore, alloying with non-precious metals is a major strategy for enhancing palladium catalytic performance. The introduction of non-precious metals not only reduces catalyst cost but also further optimizes the electronic structure of palladium sites, improving catalytic activity. Besides alloying with metals, non-metallic atom doping can also effectively control the lattice strain of the catalyst, adjusting the adsorption energy of alcohols and their intermediates on the catalyst surface, thereby significantly enhancing the activity and stability of electrocatalytic alcohol oxidation.

[0004] There are no reports yet on the technology for preparing two-dimensional nanomaterials by combining two strategies: alloying non-precious metal elements with palladium-based materials and doping with non-metallic atoms. Summary of the Invention

[0005] To address the problems of high cost, poor activity, and poor stability of current direct alcohol fuel cell anode catalysts, this invention provides a novel method for preparing phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials, and applies them to the catalytic oxidation reaction of alcohols in direct alcohol fuel cell anodes, thereby reducing catalyst cost, improving catalytic performance, and promoting the development of clean energy technologies.

[0006] This invention integrates alloying of metallic elements with palladium-based materials and non-metallic atom doping strategies, employing a wet chemical method to prepare a two-dimensional ultrathin PdMo alloy through alloying of palladium acetylacetonate and molybdenum hexacarbonyl. Using the prepared PdMo alloy as a template, P-PdMo two-dimensional nanomaterials are prepared through a tris(dimethylamino)phosphine phosphide phosphating strategy. The surface ligands of the nanomaterials are removed by acetic acid to prepare a carbon-supported P-PdMo catalyst. The carbon-supported P-PdMo nanomaterials, used as catalysts for the electrocatalytic oxidation of methanol, ethanol, ethylene glycol, and glycerol, exhibit superior activity and stability for these four alcohols compared to carbon-supported two-dimensional PdMo alloys and commercial Pd / C catalysts, demonstrating significant application potential in direct alcohol fuel cells.

[0007] On the one hand, the present invention provides a method for preparing phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials, comprising the following steps:

[0008] The palladium precursor palladium acetylacetonate, the molybdenum precursor molybdenum hexacarbonyl, and the reducing agent L-ascorbic acid were dissolved in a reaction flask containing oleylamine solution. The reaction flask was sealed, and the precursors were thoroughly mixed and dissolved by sonication. The reaction was carried out at 60–80 °C for 12 hours. Then, tris(dimethylamino)phosphine was injected into the reaction flask, and the temperature was raised to 80–100 °C to continue the reaction for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and the product was transferred to a centrifuge tube. Chloroform and ethanol were added to the centrifuge tube, and the mixture was sonicated and washed by centrifugation. The supernatant was discarded. The collected lower precipitate was dispersed by sonication with chloroform, and then ethanol was added and mixed thoroughly before centrifugation and washing. The above washing operation was repeated several times. Finally, the bottom product was collected to obtain a phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterial, abbreviated as P-PdMo material.

[0009] Furthermore, the ratio of the amounts of palladium acetylacetone, molybdenum hexacarbonyl, L-ascorbic acid, oleylamine, and tris(dimethylamino)phosphine is 20 mg: 10 mg: 60 mg: 10 mL: 0.1 mL; during centrifugation and washing, the volume ratio of chloroform and ethanol is 1:4.

[0010] On the other hand, the invention also provides the application of the phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials prepared in this invention for the electrocatalytic oxidation of alcohols in fuel cells. The specific steps are as follows:

[0011] (1) Add toluene to P-PdMo material, sonicate until homogeneous, add dried carbon black, continue sonicating until P-PdMo material is uniformly loaded on carbon black; after loading, centrifuge and wash, discard the supernatant; add chloroform and sonicate to disperse, then add ethanol, mix evenly, centrifuge and wash, discard the supernatant, repeat the washing operation of chloroform and ethanol on the precipitate several times, and finally collect the bottom precipitate.

[0012] (2) Add acetic acid to the bottom precipitate obtained in step (1) and sonicate to dissolve it to remove the small amount of residual surface ligands; then centrifuge, add chloroform and ethanol again to dissolve and centrifuge and wash, and repeat the washing of the precipitate with chloroform and ethanol several times. After drying, carbon-supported P-PdMo catalyst is obtained.

[0013] (3) The carbon-supported P-PdMo catalyst obtained in step (2) is dispersed in isopropanol and then ultrasonically mixed with deionized water and naphthol to prepare a carbon-supported P-PdMo catalyst dispersion.

[0014] (4) The carbon-supported P-PdMo catalyst dispersion was uniformly drop-coated onto the surface of a glassy carbon electrode. The resulting carbon-supported P-PdMo electrode was used as the working electrode, with an Hg / HgO electrode as the reference electrode and a platinum mesh as the counter electrode. The electrolytes were 1M KOH + 1M methanol solution, 1M KOH + 1M ethanol solution, 1M KOH + 1M ethylene glycol solution, and 1M KOH + 1M glycerol solution. The performance of electrocatalytic alcohol oxidation was tested using a three-electrode system on an electrochemical workstation CHI 660E.

[0015] In step (1), the ratio of P-PdMo material, toluene and carbon black is 2 mg: 3 mL: 2.5 mg; the type of carbon black is SuperP.

[0016] In step (2), the concentration of acetic acid is 1 mol / L.

[0017] In steps (1) to (2), the volume ratio of chloroform to ethanol during centrifugal washing is 1:4.

[0018] In step (3), the ratio of carbon-supported P-PdMo catalyst, isopropanol, deionized water and naphthol is 3 mg: 235 μL: 750 μL: 15 μL, wherein the mass percentage concentration of naphthol is 10%.

[0019] The beneficial effects of this invention are as follows:

[0020] The P-PdMo material preparation method described in this invention is simple, and the prepared material has an ultrathin two-dimensional structure and good dispersibility. The prepared carbon-supported P-PdMo catalyst exhibits excellent electrocatalytic oxidation activity and stability for various alcohols, with mass activities reaching as high as 2.32 Å mg for the electrocatalytic oxidation of methanol, ethanol, ethylene glycol, and glycerol. -1 Pd 4.95Amg -1 Pd 4.06 mg -1 Pd 4.98Amg -1 Pd It has important application prospects in new energy technologies such as direct alcohol fuel cells. Attached Figure Description

[0021] Figure 1 The images show transmission electron microscopy (a), scanning transmission electron microscopy (b), atomic force microscopy (c), and elemental distribution (d) of the P-PdMo material obtained in Example 1.

[0022] Figure 2 Transmission electron microscope (A) and high-resolution electron microscope (B) images of the PdMo alloy two-dimensional nanomaterials obtained in Comparative Example 1.

[0023] Figure 3 The cyclic voltammogram (a) and the time-current curve (b) of the chronovoltammogram were compared between the carbon-supported P-PdMo catalyst, the carbon-supported PdMo catalyst, and the commercial Pd / C catalyst in the electrocatalytic methanol oxidation reaction in a 1M KOH + 1M methanol mixture.

[0024] Figure 4 The cyclic voltammogram (a) and the time-current curve (b) of the chronovoltammogram were compared between the carbon-supported P-PdMo catalyst, the carbon-supported PdMo catalyst, and the commercial Pd / C catalyst in the electrocatalytic oxidation of ethanol in a mixture of 1M KOH and 1M ethanol in Application Example 2.

[0025] Figure 5 The cyclic voltammogram (a) and the time-current curve (b) of the chronovoltammogram were compared between the carbon-supported P-PdMo catalyst, the carbon-supported PdMo catalyst, and the commercial Pd / C catalyst in the electrocatalytic oxidation of ethylene glycol in a 1M KOH + 1M ethylene glycol mixture.

[0026] Figure 6 The cyclic voltammogram (a) and the time-current curve (b) of the chronovoltammogram were compared between the carbon-supported P-PdMo catalyst, the carbon-supported PdMo catalyst, and the commercial Pd / C catalyst in the electrocatalytic oxidation of glycerol in a 1M KOH + 1M glycerol mixture. Detailed Implementation

[0027] The invention will now be described in conjunction with specific embodiments and application examples. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, after reading the specific content of this invention, those skilled in the art can gain a clearer understanding of it and make innovations to better apply it to the preparation of phosphorus-doped palladium-based alloy ultrathin two-dimensional nanomaterial catalysts and its application in direct alcohol fuel cells.

[0028] Example

[0029] A method for preparing phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials includes the following steps:

[0030] (1) 20 mg of palladium acetylacetone, 10 mg of molybdenum hexacarbonyl, 60 mg of L-ascorbic acid, and 10 mL of oleylamine were added to a glass bottle. The bottle was sealed and sonicated at room temperature for 1 hour until the reactants were completely dissolved. Then, the mixture was placed at 60 °C and stirred at 600 rpm for 12 hours. Then, 0.1 mL of tris(dimethylamino)phosphine was added to the reaction solution, the temperature was raised to 80 °C, and the reaction was maintained at this temperature for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was transferred to a centrifuge tube. Chloroform and ethanol were added, and the mixture was centrifuged and washed at 8000 rpm. The supernatant was discarded, and the precipitate was repeatedly centrifuged and washed with chloroform and ethanol more than three times to obtain P-PdMo material with a two-dimensional nanostructure.

[0031] Figure 1 The images show transmission electron microscopy (TEM) (a) and scanning transmission electron microscopy (STEM) images (b) of the P-PdMo ultrathin two-dimensional nanomaterials prepared in Example 1. Both images demonstrate that the prepared nanomaterials exhibit good dispersibility and a thin, curved two-dimensional structure with a lateral dimension of approximately several hundred nanometers. Atomic force microscopy (AFM) shows that the thickness of the two-dimensional nanomaterials is approximately 1.2 nanometers, verifying its ultrathin structural characteristics. Elemental distribution diagram (d) shows that the prepared nanomaterials contain Pd, Mo, and P elements, and that each element is uniformly distributed on the nanomaterial, indicating the successful preparation of phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials.

[0032] The aforementioned phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials were used to prepare carbon-supported P-PdMo catalysts, which were then used as anode catalysts in alkaline direct alcohol fuel cells for electrocatalytic alcohol oxidation reactions.

[0033] (2) Add 3 mL of toluene to the P-PdMo material prepared above, and then sonicate until uniform. Add 2.5 mg of carbon black to the solution and continue sonicating for 1 hour. Then transfer the mixture to a centrifuge tube, centrifuge and wash at 8000 rpm, discard the supernatant, add 1 mL of chloroform to the bottom precipitate and sonicate to dissolve, then add 4 mL of ethanol and centrifuge and wash. Repeat the washing operation more than three times and collect the precipitate.

[0034] Add 1 mol / L acetic acid solution to the precipitate and transfer to a glass bottle, sonicating for 2 hours. Transfer the solution to a centrifuge tube, centrifuge at 8000 rpm, discard the supernatant, add 1 mL of chloroform to the precipitate and sonicate to dissolve, then add 4 mL of ethanol and centrifuge. Repeat the washing process at least three times. Finally, dry the bottom product in a fume hood to obtain the carbon-supported P-PdMo catalyst.

[0035] (3) Take 3 mg of carbon-supported P-PdMo catalyst and mix it with 235 μL of isopropanol, 750 μL of deionized water and 15 μL of 10% Nafion solution. After ultrasonic treatment for 3 hours, a uniformly dispersed carbon-supported P-PdMo catalyst dispersion is obtained.

[0036] 3 μL of catalyst dispersion was pipetted onto the surface of a glassy carbon electrode (3 mm in diameter) and allowed to dry naturally at room temperature to prepare a carbon-supported P-PdMo electrode.

[0037] Comparative Example 1

[0038] (1) A method for preparing palladium-molybdenum alloy ultrathin two-dimensional nanomaterial catalysts, comprising the following steps:

[0039] 20 mg of palladium acetylacetone, 10 mg of molybdenum hexacarbonyl, 60 mg of L-ascorbic acid, and 10 mL of oleylamine were added to a glass bottle. The bottle was sealed and sonicated at room temperature for 1 hour until the reactants were completely dissolved. Then, the mixture was placed at 60°C and stirred at 600 rpm for 12 hours. After the reaction was complete, the mixture was cooled to room temperature, transferred to a centrifuge tube, and chloroform and ethanol were added. The mixture was centrifuged and washed at 8000 rpm, and the supernatant was discarded. The precipitate was then washed repeatedly with chloroform and ethanol at least three times to obtain PdMo alloy two-dimensional nanomaterials.

[0040] Figure 2 The transmission electron microscope (TEM) image (a) and high-resolution TEM image (b) of the PdMo alloy ultrathin two-dimensional nanomaterial prepared in Comparative Example 1 show that the prepared PdMo alloy nanomaterial has an ultrathin two-dimensional structure, size and good dispersibility similar to P-PdMo, indicating that the palladium-molybdenum alloy ultrathin two-dimensional nanomaterial was successfully prepared.

[0041] (2) Add 3 mL of toluene to the PdMo nanomaterials prepared above, and then sonicate until uniform. Add 2.5 mg of carbon black to the solution and continue sonicating for 1 hour. Then transfer the mixture to a centrifuge tube, centrifuge and wash at 8000 rpm, discard the supernatant, add 1 mL of chloroform to the bottom precipitate and sonicate to dissolve, then add 4 mL of ethanol and centrifuge and wash. Repeat the washing operation more than three times and collect the precipitate.

[0042] Add 1 mol / L acetic acid solution to the precipitate and transfer to a glass bottle, sonicating for 2 hours. Transfer the solution to a centrifuge tube, centrifuge at 8000 rpm, discard the supernatant, add 1 mL of chloroform to the precipitate and sonicate to dissolve, then add 4 mL of ethanol and centrifuge. Repeat the washing operation at least three times. Finally, place the bottom product in a fume hood to dry, obtaining the carbon-supported PdMo catalyst.

[0043] (3) Take 3 mg of carbon-supported PdMo catalyst and mix it with 235 μL of isopropanol, 750 μL of deionized water and 15 μL of 10% Nafion solution. After ultrasonic treatment for 3 hours, a uniformly dispersed carbon-supported PdMo catalyst dispersion is obtained.

[0044] 3 μL of catalyst dispersion was pipetted onto the surface of a glassy carbon electrode and allowed to dry naturally at room temperature to prepare a carbon-supported PdMo electrode.

[0045] Comparative Example 2

[0046] A method for preparing a commercial palladium-on-carbon catalyst includes the following steps:

[0047] 3 mg of commercial palladium-on-carbon catalyst was mixed with 235 μL of isopropanol, 750 μL of deionized water, and 15 μL of 10% Nafion solution. After ultrasonic treatment for 3 hours, a uniformly dispersed commercial palladium-on-carbon catalyst dispersion was obtained.

[0048] 3 μL of catalyst dispersion was pipetted onto the surface of a glassy carbon electrode and allowed to dry naturally at room temperature to prepare an electrode with a commercial palladium-on-carbon catalyst.

[0049] Application Example 1

[0050] The steps for testing the performance of electrocatalytic methanol oxidation reaction are as follows:

[0051] The carbon-supported P-PdMo electrode from Example 1, the carbon-supported PdMo electrode from Comparative Example 1, and the palladium-on-carbon catalyst electrode from Comparative Example 2 were used as working electrodes, with an Hg / HgO electrode as the reference electrode, a platinum mesh as the counter electrode, and a 1M KOH + 1M methanol solution as the electrolyte. Cyclic voltammetry and chronopotentiometric methods were performed on an electrochemical workstation. The scan rate for cyclic voltammetry was 50 mV / s. -1 The potential measured by the chronopotential method is -0.2V relative to the Hg / HgO reference electrode.

[0052] Figure 3 Figure a shows a comparison of the cyclic voltammetry curves for methanol oxidation using different catalysts in this application example. The carbon-supported P-PdMo electrode exhibits the best mass activity at 2.32 Amg. -1 Pd The mass activity of the carbon-supported PdMo electrode in Comparative Example 1 was 1.41 Amg. -1 Pd The mass activity of the commercial palladium-carbon electrode in Comparative Example 2 was 0.53 A mg. -1 Pd This indicates that the phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterial catalyst can significantly improve the activity of electrocatalytic methanol oxidation reaction compared with commercial palladium-carbon and undoped PdMo alloy catalysts.

[0053] Figure 3 Figure b shows a comparison of the chronopotential coefficient curves of methanol oxidation using different catalysts in this application example. During the 12-hour test period, the carbon-supported P-PdMo electrode exhibited higher mass activity compared to the carbon-supported PdMo alloy electrode in Comparative Example 1 and the commercial palladium-carbon electrode in Comparative Example 2. This indicates that the phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional structure catalyst can significantly improve the stability of the electrocatalytic methanol oxidation reaction.

[0054] Application Example 2

[0055] The steps for testing the performance of electrocatalytic ethanol oxidation reaction are as follows:

[0056] The carbon-supported P-PdMo electrode from the examples, the carbon-supported PdMo electrode from Comparative Example 1, and the palladium-on-carbon catalyst electrode from Comparative Example 2 were used as working electrodes, with an Hg / HgO electrode as the reference electrode and a platinum mesh as the counter electrode. A 1M KOH + 1M ethanol solution was used as the electrolyte. Cyclic voltammetry and chronopotentiometric methods were performed on an electrochemical workstation. The scan rate for the cyclic voltammetry was 50 mV / s. -1 The potential measured by the chronopotential method is -0.2V relative to the Hg / HgO reference electrode.

[0057] Figure 4Figure a shows a comparison of cyclic voltammetry curves for ethanol oxidation using different catalysts in this application example. The carbon-supported P-PdMo electrode exhibits the best mass activity at 4.95 A mg. -1 Pd The mass activity of the carbon-supported PdMo electrode in Comparative Example 1 was 2.94 Amg. -1 Pd The mass activity of the commercial palladium-carbon electrode in Comparative Example 2 was 1.53 A mg. -1 Pd This indicates that the phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterial catalyst can significantly improve the activity of electrocatalytic ethanol oxidation reaction compared with commercial palladium-carbon and undoped PdMo alloy catalysts.

[0058] Figure 4 Figure b shows a comparison of the chronopotential coefficient curves of different catalysts in this application example for ethanol oxidation. During the 12-hour test period, the carbon-supported P-PdMo electrode showed higher mass activity compared to the carbon-supported PdMo alloy electrode in Comparative Example 1 and the commercial palladium-carbon electrode in Comparative Example 2. This indicates that the phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional structure catalyst can significantly improve the stability of the electrocatalytic ethanol oxidation reaction.

[0059] Application Example 3

[0060] The steps for testing the performance of electrocatalytic ethylene glycol oxidation reaction are as follows:

[0061] The carbon-supported P-PdMo electrode from the examples, the carbon-supported PdMo electrode from Comparative Example 1, and the palladium-on-carbon catalyst electrode from Comparative Example 2 were used as working electrodes, with an Hg / HgO electrode as the reference electrode and a platinum mesh as the counter electrode. A 1M KOH + 1M ethylene glycol solution was used as the electrolyte. Cyclic voltammetry and chronopotentiometric methods were performed on an electrochemical workstation. The scan rate for the cyclic voltammetry was 50 mV / s. -1 The potential measured by the chronopotential method is -0.2V relative to the Hg / HgO reference electrode.

[0062] Figure 5 Figure a shows a comparison of cyclic voltammetry curves for ethylene glycol oxidation using different catalysts in this application example. The carbon-supported P-PdMo electrode exhibits the best mass activity at 4.06 A mg. -1 Pd The mass activity of the carbon-supported PdMo electrode in Comparative Example 1 was 2.66 Amg. -1 Pd The mass activity of the commercial palladium-carbon electrode in Comparative Example 2 was 1.25 A mg. -1 PdThis indicates that the phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterial catalyst can significantly improve the activity of electrocatalytic ethylene glycol oxidation reaction compared with commercial palladium-carbon and undoped PdMo alloy catalysts.

[0063] Figure 5 Figure b shows a comparison of the chronopotential curves of ethylene glycol oxidation using different catalysts in this application example. During the 12-hour test period, the carbon-supported P-PdMo electrode exhibited higher mass activity compared to the carbon-supported PdMo alloy electrode in Comparative Example 1 and the commercial palladium-carbon electrode in Comparative Example 2. This indicates that the phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional structure catalyst can significantly improve the stability of the electrocatalytic ethylene glycol oxidation reaction.

[0064] Application Example 4

[0065] The steps for testing the performance of the electrocatalytic glycerol oxidation reaction are as follows:

[0066] The carbon-supported P-PdMo electrode from the examples, the carbon-supported PdMo electrode from Comparative Example 1, and the palladium-on-carbon catalyst electrode from Comparative Example 2 were used as working electrodes, with an Hg / HgO electrode as the reference electrode and a platinum mesh as the counter electrode. A 1M KOH + 1M glycerol solution was used as the electrolyte. Cyclic voltammetry and chronopotentiometric methods were performed on an electrochemical workstation. The scan rate for the cyclic voltammetry was 50 mV / s. -1 The potential measured by the chronopotential method is -0.2V relative to the Hg / HgO reference electrode.

[0067] Figure 6 Figure a shows a comparison of the cyclic voltammetry curves for the oxidation of glycerol with different catalysts in this application example. The carbon-supported P-PdMo electrode exhibits the best mass activity at 4.98 A mg. -1 Pd The mass activity of the carbon-supported PdMo electrode in Comparative Example 1 was 3.39 A mg. -1 Pd The mass activity of the commercial palladium-carbon electrode in Comparative Example 2 was 2.07 A mg. -1 Pd This indicates that the phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterial catalyst can significantly improve the activity of electrocatalytic glycerol oxidation reaction compared with commercial palladium-carbon and undoped PdMo alloy catalysts.

[0068] Figure 6Figure b shows a comparison of the chronopotential curves of glycerol oxidation using different catalysts in this application example. During the 12-hour test period, the carbon-supported P-PdMo electrode exhibited higher mass activity compared to the carbon-supported PdMo alloy electrode in Comparative Example 1 and the commercial palladium-carbon electrode in Comparative Example 2. This indicates that the phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional structure catalyst can significantly improve the stability of the electrocatalytic glycerol oxidation reaction.

[0069] The above description is merely an embodiment and application example of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials, characterized in that, Includes the following steps: The palladium precursor palladium acetylacetonate, the molybdenum precursor molybdenum hexacarbonyl, and the reducing agent L-ascorbic acid were dissolved in a reaction flask containing oleylamine solution. The reaction flask was sealed, and the precursors were thoroughly mixed and dissolved by sonication. The reaction was carried out at 60–80 °C. Then, tris(dimethylamino)phosphine was injected into the reaction flask, and the temperature was raised to 80–100 °C to continue the reaction. After the reaction was completed, the mixture was cooled to room temperature, and the product was transferred to a centrifuge tube. Chloroform and ethanol were added to the centrifuge tube, and the mixture was sonicated and washed by centrifugation. The supernatant was discarded. The collected lower precipitate was dispersed by sonication with chloroform, and then ethanol was added and mixed thoroughly before centrifugation and washing. The above washing operation was repeated several times. Finally, the bottom product was collected to obtain a phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterial, abbreviated as P-PdMo material.

2. The method for preparing phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials as described in claim 1, characterized in that, The ratio of acetylacetone palladium, hexacarbonyl molybdenum, L-ascorbic acid, oleylamine and tris(dimethylamino)phosphine is 20 mg: 10 mg: 60 mg: 10 mL: 0.1 mL.

3. The method for preparing phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials as described in claim 1, characterized in that, The reaction time is 12 hours at 60-80℃; the reaction time is continued for 6 hours at 80-100℃.

4. The method for preparing phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials as described in claim 1, characterized in that, During centrifugal washing, the volume ratio of chloroform to ethanol is 1:

4.

5. The use of the phosphorus-doped palladium-molybdenum alloy ultrathin two-dimensional nanomaterials prepared by the preparation method according to any one of claims 1 to 4 for electrocatalytic alcohol oxidation reaction in fuel cells.

6. The use as described in claim 5, characterized in that, The specific steps are as follows: (1) Add toluene to P-PdMo material, sonicate until homogeneous, add dried carbon black, continue sonicating until P-PdMo material is uniformly loaded on carbon black; after loading, centrifuge and wash, discard the supernatant; add chloroform and sonicate to disperse, then add ethanol, mix evenly, centrifuge and wash, discard the supernatant, repeat the washing operation of chloroform and ethanol on the precipitate several times, and finally collect the bottom precipitate. (2) Add acetic acid to the bottom precipitate obtained in step (1) and sonicate to dissolve it to remove the small amount of residual surface ligands; then centrifuge, add chloroform and ethanol again to dissolve and centrifuge and wash, and repeat the washing of the precipitate with chloroform and ethanol several times. After drying, carbon-supported P-PdMo catalyst is obtained. (3) Dissolve the carbon-supported P-PdMo catalyst obtained in step (2) with isopropanol, and then mix it with deionized water and naphthol by ultrasonication to prepare a carbon-supported P-PdMo catalyst dispersion. (4) The carbon-supported P-PdMo catalyst dispersion was uniformly drop-coated onto the surface of a glassy carbon electrode. The resulting carbon-supported P-PdMo electrode was used as the working electrode, the Hg / HgO electrode was used as the reference electrode, and the platinum mesh was used as the counter electrode. The three-electrode system was used to carry out the electrocatalytic alcohol oxidation reaction.

7. The use as described in claim 6, characterized in that, In step (1), the ratio of P-PdMo material, toluene and carbon black is 2 mg: 3 mL: 2.5 mg; the type of carbon black is SuperP.

8. The use as described in claim 6, characterized in that, In step (2), the concentration of acetic acid is 1 mol / L.

9. The use as described in claim 6, characterized in that, In steps (1) to (2), the volume ratio of chloroform to ethanol during centrifugal washing is 1:

4.

10. The use as described in claim 6, characterized in that, In step (3), the ratio of carbon-supported P-PdMo catalyst, isopropanol, deionized water and naphthol is 3 mg: 235 μL: 750 μL: 15 μL, wherein the mass percentage concentration of naphthol is 10%.

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