A molybdenum-based low-platinum electrocatalyst and its preparation method and application in proton exchange membrane fuel cells

Abstract

The present invention discloses a molybdenum-based low-platinum electrocatalyst and a preparation method thereof and an application in a proton exchange membrane fuel cell, and belongs to the technical field of fuel cells. The present invention overcomes the disadvantages of existing noble metal electrocatalysts such as high cost and easy deactivation. The present invention synthesizes a variety of molybdenum-based or molybdenum-containing nickel-based bimetallic compounds, such as molybdenum carbide, nickel molybdenum carbide, molybdenum nitride, nickel molybdenum nitride, molybdenum phosphide, and nickel molybdenum phosphide, by combining the confinement effect of nitrogen-containing heteroatoms in nitrogen-containing ligands with a thermal decomposition method, and further loads a low content of platinum (such as metallic platinum, platinum nickel, platinum cobalt, platinum iron) to obtain a molybdenum-based low-platinum electrocatalyst, which has an ultra-thin nanosheet structure, can perform rapid mass transfer and electron transfer, and not only has excellent HOR performance, but also can provide a larger power density and anti-CO poisoning effect as an anode material of a proton exchange membrane fuel cell, and has great potential to replace commercial Pt / C catalysts.

Description

Technical Field

[0001] The invention relates to a molybdenum-based low-platinum electrocatalyst and a preparation method thereof and application in a proton exchange membrane fuel cell, belonging to the technical field of fuel cells. Background Art

[0002] Proton Exchange Membrane Fuel Cell (PEMFC) is a new type of energy conversion device that is efficient and environmentally friendly. It is widely studied and applied in electric vehicles, portable electronic devices, and distributed energy systems. PEMFC is a device based on electrochemical principles that generates electricity by reacting hydrogen with oxygen. Its core component is the proton exchange membrane (PEM). Protons are transferred through the membrane, and electrons flow through the external circuit, ultimately generating electricity and water. Compared with traditional combustion power generation methods, PEMFC has the advantages of high efficiency, zero emissions, and fast startup response.

[0003] However, the commercial application of PEMFC still faces some challenges. One of them is that precious metal catalysts (such as platinum) have limiting factors such as high cost and low abundance. Secondly, precious metal catalysts (such as platinum) are easily poisoned by trace amounts of CO in gas impurities. Therefore, it is necessary to develop a catalyst with low platinum content and excellent resistance to CO poisoning to promote the commercial development of PEMFC. Summary of the invention

[0004] In order to reduce the platinum content of an electrocatalyst, the present invention provides a molybdenum-based low-platinum electrocatalyst and a preparation method thereof and application in a proton exchange membrane fuel cell.

[0005] The technical solution of the present invention:

[0006] One of the objects of the present invention is to provide a method for preparing a molybdenum-based low-platinum electrocatalyst, the method comprising the following steps:

[0007] (1) dissolving a carbon source in an organic solvent, then adding a molybdenum source, and stirring until the carbon source is completely dissolved to obtain a molybdenum salt solution;

[0008] (2) continue to add nitrogen-containing ligands and perform ultrasonic treatment until uniform mixing;

[0009] (3) subjecting the uniform mixed solution obtained in (2) to a water bath reaction to obtain a carbon / molybdenum nitride precursor;

[0010] (4) heat treating the carbon / molybdenum nitride precursor in a nitrogen atmosphere, an argon atmosphere containing a phosphorus source, or an ammonia atmosphere to obtain a molybdenum-containing compound;

[0011] (5) mixing a platinum source and a transition metal source and subjecting the mixture to a high temperature sintering treatment to obtain a platinum-containing alloy material;

[0012] (6) The platinum-containing alloy material is loaded onto the molybdenum-containing compound using a reduction method to obtain a molybdenum-based low-platinum electrocatalyst.

[0013] It is further defined that the carbon source in (1) is reduced graphene oxide.

[0014] It is further defined that the molybdenum source in (1) is ammonium molybdate, sodium molybdate, phosphomolybdic acid, zinc molybdate or magnesium molybdate.

[0015] It is further defined that the nickel source is nickel chloride, nickel sulfate or nickel nitrate.

[0016] It is further defined that the mole ratio of the molybdenum source to the nickel source is 1:(1-2.5).

[0017] It is further defined that the mass ratio of the carbon source to the organic solvent in (1) is 1:(1-20).

[0018] It is further defined that the mass ratio of the molybdenum source to the carbon source in (1) is 1:(50-100).

[0019] Further defined, the nitrogen-containing ligand in (2) is o-phenanthroline (C 10 H8N2), ammonia (NH3.H2O), pyridine (C5H5N), diazabiphenyl (phen), tetraazacyclohexane (cyclam) or pentaazacyclohexanedione (dipyridyl).

[0020] It is further defined that the mass ratio of the nitrogen-containing ligand to the molybdenum source in (2) is 1:(2-10).

[0021] It is further defined that the water bath reaction treatment conditions in (3) are: temperature 120°C to 150°C, time 10h to 20h.

[0022] It is further defined that the heat treatment conditions in (4) are: heating to 800-1000°C at a rate of 10°C / min and keeping the temperature for 1.5-3.5h.

[0023] It is further defined that the phosphorus source in (4) is NaH2PO2 or NH4H2PO2.

[0024] It is further defined that in (5), the platinum source is chloroplatinic acid, ammonium platinate or sodium chloroplatinate (IV).

[0025] It is further defined that the transition metal source in (5) is a mixture of one or more of nickel chloride, nickel nitrate, ferric acetylacetonate, ferric chloride, cobalt nitrate and cobalt chloride.

[0026] It is further defined that the reduction method in (6) is ethylene glycol reduction method, sodium borohydride reduction method, hydrogen reduction method or photoreduction method.

[0027] The second object of the present invention is to provide a molybdenum-based low-platinum electrocatalyst obtained by the above-mentioned preparation method, which is used for preparing the anode working electrode of a proton exchange membrane fuel cell.

[0028] A third object of the present invention is to provide a proton exchange membrane fuel cell, which comprises the above-mentioned anode working electrode.

[0029] Beneficial effects:

[0030] The present invention synthesizes a variety of molybdenum-based or molybdenum-containing nickel-based bimetallic compounds such as molybdenum carbide, nickel molybdenum carbide, molybdenum nitride, nickel molybdenum nitride, molybdenum phosphide, and nickel molybdenum phosphide through the confinement effect of nitrogen-containing heteroatoms in nitrogen-containing ligands combined with a thermal decomposition method, and further loads a low content of platinum (such as metallic platinum, platinum nickel, platinum cobalt, and platinum iron) to obtain a molybdenum-based low-platinum electrocatalyst. The catalyst has an ultra-thin nanosheet structure that can perform rapid mass transfer and electron transfer. It not only has excellent HOR performance, but also can provide a larger power density and anti-CO poisoning effect as an anode material for proton exchange membrane fuel cells, and has great potential to replace commercial Pt / C catalysts. Experimental studies have shown that the power density of a proton exchange membrane battery assembled using the electrocatalyst provided by the present invention can reach 2.01W·cm -2 , while the power density of commercial Pt / C assembled fuel cells is only 1.71 W·cm -2 Moreover, the Pt(PtNi)-Mo(MoNi)C(N, P) / GN catalyst can maintain 1.26 W·cm in hydrogen containing 10 ppm CO. -2 The power density of commercial Pt / C under the same conditions is 0.54 W·cm -2 , the power density drops seriously. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a scanning electron microscope photograph of the molybdenum-based low-platinum electrocatalyst prepared in Example 1;

[0032] Figure 2 Electrochemical performance curves of the molybdenum-based low-platinum electrocatalysts prepared in Example 1, Example 2 and Example 3 in 0.1M HClO4 solution and saturated hydrogen conditions;

[0033] Figure 3 Electrochemical performance curves of the electrocatalysts prepared in Example 7, Example 8 and Example 9 in 0.1M HClO4 solution and saturated hydrogen conditions;

[0034] Figure 4The electrochemical performance curves of the electrocatalysts prepared in Example 1 and Comparative Example 2 in 0.1M HClO4 solution and saturated hydrogen conditions;

[0035] Figure 5 Electrochemical performance curves of the electrocatalysts prepared in Example 6, Example 7 and Comparative Example 1 in 0.1M HClO4 solution and saturated hydrogen conditions;

[0036] Figure 6 Electrochemical performance curves of the electrocatalysts prepared in Example 7 and Example 1 tested in 0.1M HClO4 solution containing 1000ppm CO in H2;

[0037] Figure 7 Fuel performance curve of a fuel cell assembled with the electrocatalyst prepared in Example 1 tested under H2-O2 and 10 ppm CO / H2-O2 gas;

[0038] Figure 8 Fuel performance curve of a fuel cell assembled with the electrocatalyst prepared in Example 7 tested under H2-O2 and 10 ppm CO / H2-O2 gases. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0040] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0041] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0042] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0043] Embodiment 1:

[0044] The preparation method of the molybdenum-based low-platinum electrocatalyst provided in this embodiment is carried out according to the following steps:

[0045] Step 1: Disperse 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol, then add 0.247 g of ammonium molybdate, and stir until completely dissolved to obtain a graphene ammonium molybdate salt solution mixture;

[0046] Step 2: Add 0.08 g of o-phenanthroline to the graphene ammonium molybdate solution mixture prepared above, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0047] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a molybdenum carbon (nitride) precursor;

[0048] Step 4: heat-treating the molybdenum carbide (nitride) precursor obtained in step 3 in a nitrogen atmosphere at 900° C. (one-third of the mass of the heat-treated catalyst) for 2.5 h at a heating rate of 10° C. / min to obtain molybdenum carbide;

[0049] Step 5: Mix chloroplatinic acid and nickel chloride in a mass ratio of 3 mg:5 mg, and calcine for 2 hours in an argon atmosphere at 1000° C. to prepare a platinum-containing alloy material;

[0050] Step 6: Use ethylene glycol reduction method to load the platinum-containing alloy material prepared in step 5 on the molybdenum carbide obtained in step 4 to obtain a molybdenum-based low-platinum electrocatalyst, and the Pt loading is 3%. The specific operation process is: 50 mg of molybdenum carbide (nitrogen, phosphorus) and 1 mg of the platinum-containing alloy material prepared in step 5 are dispersed in 100 mL of ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named PtNi-MoC / GN.

[0051] The surface microstructure of the electrocatalyst PtNi-MoC / GN prepared in this example was tested. Figure 1 As shown by Figure 1 As shown, the catalyst has a uniform flake structure with a larger surface area and higher proton transfer efficiency.

[0052] Embodiment 2:

[0053] The preparation method of the molybdenum-based low-platinum electrocatalyst provided in this embodiment is carried out according to the following steps:

[0054] Step 1: Disperse 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol, then add 0.247 g of ammonium molybdate, and stir until completely dissolved to obtain a graphene ammonium molybdate salt solution mixture;

[0055] Step 2: Add 0.08 g of o-phenanthroline to the graphene ammonium molybdate solution mixture prepared above, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0056] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a molybdenum carbon (nitride) precursor;

[0057] Step 4: heat-treating the molybdenum carbide (nitride) precursor obtained in step 3 in an ammonia atmosphere at 900° C. (one-third of the mass of the heat-treated catalyst) for 2.5 h at a heating rate of 10° C. / min to obtain molybdenum carbide;

[0058] Step 5: Mix chloroplatinic acid and nickel chloride in a mass ratio of 3 mg:5 mg, and calcine for 2 hours in an argon atmosphere at 1000° C. to prepare a platinum-containing alloy material;

[0059] Step 6: Use ethylene glycol reduction method to load the platinum-containing alloy material prepared in step 5 on the molybdenum nitride obtained in step 4 to obtain a molybdenum-based low-platinum electrocatalyst, and the Pt loading amount is 3%. The specific operation process is: 50 mg of molybdenum nitride and 1 mg of the platinum-containing alloy material prepared in step 5 are dispersed in 100 mL of ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named PtNi-MoN / GN.

[0060] Embodiment 3:

[0061] The preparation method of the molybdenum-based low-platinum electrocatalyst provided in this embodiment is carried out according to the following steps:

[0062] Step 1: Disperse 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol, then add 0.247 g of ammonium molybdate, and stir until completely dissolved to obtain a graphene ammonium molybdate salt solution mixture;

[0063] Step 2: Add 0.08 g of o-phenanthroline to the graphene ammonium molybdate solution mixture prepared above, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0064] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a molybdenum carbon (nitride) precursor;

[0065] Step 4: heat-treat the molybdenum carbon (nitride) precursor obtained in step 3 in an argon atmosphere containing NaH2PO2 at 900°C for 2.5h (one third of the mass of the heat-treated catalyst) at a heating rate of 10°C / min to obtain molybdenum carbon phosphide;

[0066] Step 5: Mix chloroplatinic acid and nickel chloride in a mass ratio of 3 mg:5 mg, and calcine for 2 hours in an argon atmosphere at 1000° C. to prepare a platinum-containing alloy material;

[0067] Step 6: Use ethylene glycol reduction method to load the platinum-containing alloy material prepared in step 5 on the molybdenum phosphide obtained in step 4 to obtain a molybdenum-based low-platinum electrocatalyst, and the Pt loading amount is 3%. The specific operation process is: 50 mg of molybdenum phosphide and 1 mg of the platinum-containing alloy material prepared in step 5 are dispersed in 100 mL of ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named PtNi-MoP / GN.

[0068] Embodiment 4:

[0069] The preparation method of the molybdenum-based low-platinum electrocatalyst provided in this embodiment is carried out according to the following steps:

[0070] Step 1: Disperse 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol, then add 0.247 g of ammonium molybdate, and stir until completely dissolved to obtain a graphene ammonium molybdate salt solution mixture;

[0071] Step 2: Add 0.08 g of o-phenanthroline to the graphene ammonium molybdate solution mixture prepared above, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0072] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a molybdenum carbon (nitride) precursor;

[0073] Step 4: heat-treat the molybdenum carbon (nitride) precursor obtained in step 3 in an argon atmosphere containing NaH2PO2 at 900°C for 2.5h (one third of the mass of the heat-treated catalyst) at a heating rate of 10°C / min to obtain molybdenum phosphide;

[0074] Step 5: Use ethylene glycol reduction method to load platinum on the molybdenum phosphide obtained in step 4 to obtain a molybdenum-based low-platinum electrocatalyst, and the Pt loading amount is 3%. The specific operation process is: 50 mg of molybdenum phosphide and 1 mg of the platinum-containing alloy material prepared in step 5 are dispersed in 100 mL of ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named Pt-MoP / GN.

[0075] Embodiment 5:

[0076] The preparation method of the molybdenum-based low-platinum electrocatalyst provided in this embodiment is carried out according to the following steps:

[0077] Step 1: Disperse 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol, then add 0.247 g of ammonium molybdate, and stir until completely dissolved to obtain a graphene ammonium molybdate salt solution mixture;

[0078] Step 2: Add 0.08 g of o-phenanthroline to the graphene ammonium molybdate solution mixture prepared above, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0079] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a molybdenum carbon (nitride) precursor;

[0080] Step 4: heat-treating the molybdenum carbide (nitride) precursor obtained in step 3 in a nitrogen atmosphere at 900° C. (one-third of the mass of the heat-treated catalyst) for 2.5 h at a heating rate of 10° C. / min to obtain molybdenum carbide;

[0081] Step 5: Use ethylene glycol reduction method to load platinum on the molybdenum carbide obtained in step 4 to obtain a molybdenum-based low-platinum electrocatalyst, and the Pt loading amount is 3%. The specific operation process is: 50 mg of molybdenum carbide and 1 mg of the platinum-containing alloy material prepared in step 5 are dispersed in 100 mL of ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named Pt-MoC / GN.

[0082] Embodiment 6:

[0083] The preparation method of the molybdenum-based low-platinum electrocatalyst provided in this embodiment is carried out according to the following steps:

[0084] Step 1: Disperse 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol, then add 0.247 g of ammonium molybdate, and stir until completely dissolved to obtain a graphene ammonium molybdate salt solution mixture;

[0085] Step 2: Add 0.08 g of o-phenanthroline to the graphene ammonium molybdate solution mixture prepared above, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0086] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a molybdenum carbon (nitride) precursor;

[0087] Step 4: heat-treating the molybdenum carbon (nitride) precursor obtained in step 3 in an ammonia atmosphere at 900° C. (one third of the mass of the heat-treated catalyst) for 2.5 h at a heating rate of 10° C. / min to obtain molybdenum nitride;

[0088] Step 5: Use ethylene glycol reduction method to load platinum on the molybdenum nitride obtained in step 4 to obtain a molybdenum-based low-platinum electrocatalyst, and the Pt loading amount is 3%. The specific operation process is: 50 mg of molybdenum nitride and 1 mg of the platinum-containing alloy material prepared in step 5 are dispersed in 100 mL of ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named Pt-MoN / GN.

[0089] Embodiment 7:

[0090] The preparation method of the molybdenum-based low-platinum electrocatalyst provided in this embodiment is carried out according to the following steps:

[0091] Step 1: Disperse 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol, then add 0.247 g of ammonium molybdate and 0.355 g of nickel chloride, and stir until completely dissolved to obtain a graphene nickel chloride ammonium molybdate salt solution mixture;

[0092] Step 2: Add 0.08 g of o-phenanthroline to the prepared graphene nickel chloride ammonium molybdate solution mixture, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0093] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a molybdenum nickel carbon (nitride) precursor;

[0094] Step 4: heat-treat the molybdenum carbon (nitride) precursor obtained in step 3 in an ammonia atmosphere at 900° C. (one-third of the mass of the heat-treated catalyst) for 2.5 h at a heating rate of 10° C. / min to obtain molybdenum nickel nitride;

[0095] Step 5: Use ethylene glycol reduction method to load platinum on the molybdenum nickel nitride obtained in step 4 to obtain a molybdenum-based low-platinum electrocatalyst, and the Pt loading amount is 3%. The specific operation process is: 50 mg of molybdenum nickel nitride and 1 mg of the platinum-containing alloy material prepared in step 5 are dispersed in 100 mL of ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named Pt-MoNiN / GN.

[0096] Embodiment 8:

[0097] The preparation method of the molybdenum-based low-platinum electrocatalyst provided in this embodiment is carried out according to the following steps:

[0098] Step 1: Disperse 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol, then add 0.247 g of ammonium molybdate and 0.355 g of nickel chloride, and stir until completely dissolved to obtain a graphene ammonium molybdate salt solution mixture;

[0099] Step 2: Add 0.08 g of o-phenanthroline to the prepared graphene nickel chloride ammonium molybdate solution mixture, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0100] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a molybdenum nickel carbon (nitride) precursor;

[0101] Step 4: heat-treat the molybdenum carbide (nitride) precursor obtained in step 3 in a nitrogen atmosphere at 900° C. (one-third of the mass of the heat-treated catalyst) for 2.5 h at a heating rate of 10° C. / min to obtain molybdenum nickel carbide;

[0102] Step 5: Use ethylene glycol reduction method to load platinum on molybdenum nickel carbide obtained in step 4 to obtain a molybdenum-based low-platinum electrocatalyst, with a Pt loading of 3%. The specific operation process is: 50 mg molybdenum nickel carbide and 1 mg platinum-containing alloy material prepared in step 5 are dispersed in 100 mL ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named Pt-MoNiC / GN.

[0103] Embodiment 9:

[0104] The preparation method of the molybdenum-based low-platinum electrocatalyst provided in this embodiment is carried out according to the following steps:

[0105] Step 1: Disperse 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol, then add 0.247 g of ammonium molybdate and 0.355 g of nickel chloride, and stir until completely dissolved to obtain a graphene nickel chloride ammonium molybdate salt solution mixture;

[0106] Step 2: Add 0.08 g of o-phenanthroline to the graphene ammonium molybdate solution mixture prepared above, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0107] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a molybdenum nickel carbon (nitride) precursor;

[0108] Step 4: heat-treat the molybdenum nickel carbon (nitride) precursor obtained in step 3 in an argon atmosphere containing NaH2PO2 at 900°C for 2.5h (one third of the mass of the heat-treated catalyst) at a heating rate of 10°C / min to obtain molybdenum nickel phosphide;

[0109] Step 5: Use ethylene glycol reduction method to load platinum on the molybdenum nickel phosphide obtained in step 4 to obtain a molybdenum-based low-platinum electrocatalyst, and the Pt loading amount is 3%. The specific operation process is: 50 mg of molybdenum nickel phosphide and 1 mg of the platinum-containing alloy material prepared in step 5 are dispersed in 100 mL of ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named Pt-MoNiP / GN.

[0110] Comparative Example 1:

[0111] The preparation method of the electrocatalyst provided in this embodiment is carried out according to the following steps:

[0112] Step 1: Disperse 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol, then add 0.355 g of nickel chloride and stir until completely dissolved to obtain a graphene-nickel chloride mixture;

[0113] Step 2: Add 0.08 g of o-phenanthroline to the graphene-nickel chloride mixture prepared above, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0114] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a nickel carbon (nitride) precursor;

[0115] Step 4: heat-treating the nickel carbon (nitride) precursor obtained in step 3 in an ammonia atmosphere at 900° C. (one third of the mass of the heat-treated catalyst) for 2.5 h at a heating rate of 10° C. / min to obtain nickel nitride;

[0116] Step 5: Use ethylene glycol reduction method to load platinum on the nickel nitride obtained in step 4 to obtain a molybdenum-based low-platinum electrocatalyst, with a Pt loading of 3%. The specific operation process is: 50 mg of nickel nitride and 1 mg of the platinum-containing alloy material prepared in step 5 are dispersed in 100 mL of ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named Pt-NiN / GN.

[0117] Comparative Example 2:

[0118] The preparation method of the electrocatalyst provided in this embodiment is carried out according to the following steps:

[0119] Step 1: dispersing 20 g of reduced graphene oxide in 100 ml of anhydrous ethanol to obtain a graphene solution mixture;

[0120] Step 2: Add 0.08 g of o-phenanthroline to the graphene solution mixture prepared above, and oscillate ultrasonically for 40 min until the solution is uniformly mixed;

[0121] Step 3: Place the solution obtained in step 2 into a stainless steel high-temperature reactor and react at 130° C. for 15 h to obtain a gray solid mixture;

[0122] Step 4: heat-treat the black solid mixture obtained in step 3 (one third of the mass of the heat-treated catalyst) in a nitrogen atmosphere at 900°C for 2.5h at a heating rate of 10°C / min to obtain C,N / GN;

[0123] Step 5: Mix chloroplatinic acid and nickel chloride in a mass ratio of 3 mg:5 mg, and calcine for 2 hours in an argon atmosphere at 1000° C. to prepare a platinum-containing alloy material;

[0124] Step 6: Use ethylene glycol reduction method to load the platinum-containing alloy material prepared in step 5 on C, N / GN obtained in step 4 to obtain a low-platinum electrocatalyst, with a Pt loading of 3%. The specific operation process is: 50 mg C, N / GN and 1 mg of the platinum-containing alloy material prepared in step 5 are dispersed in 100 mL of ethylene glycol solution, stirred at 100 ° C to make it evenly dispersed, cooled after 5 hours, centrifuged at 5000 rpm, and the obtained solid is dried. The obtained electrocatalyst is named PtNi / GN.

[0125] Effect example:

[0126] (1) The electrochemical performance of the molybdenum-based low-platinum electrocatalysts prepared in Example 1, Example 2 and Example 3 was tested in a 0.1M HClO4 solution at 1600 rpm under saturated H2 conditions. The results are as follows: Figure 2 As shown by Figure 2 It can be seen that among the three PtNi alloy-supported molybdenum-based catalysts, at an overpotential of 0.1 V, the current density of PtNi-MoC / GN reached 2.89 mA cm -2 , far exceeding PtNi-MoN / GN (2.34mAcm -2 ) and PtNi-MoP / GN (2.19 mA cm -2 ).

[0127] (2) The electrochemical performance of the electrocatalysts prepared in Examples 7, 8 and 9 was tested in a 0.1 M HClO4 solution at 1600 rpm under saturated H2 conditions. The results are as follows: Figure 3 As shown by Figure 3 It can be seen that among the three Pt-loaded molybdenum-nickel-based catalysts, the current density of Pt-MoNiN / GN reached 2.91 mA cm at an overpotential of 0.1 V. -2 , far exceeding Pt-MoNiC / GN (2.64mAcm -2 ) and Pt-MoNiP / GN (2.28 mA cm-2 ).

[0128] (3) The electrochemical performance of the electrocatalysts prepared in Example 1 and Comparative Example 2 was tested in a 0.1 M HClO4 solution at 1600 rpm under saturated H2 conditions. The results are as follows: Figure 4 As shown. Figure 4 It can be seen that in the previous electrochemical test, it was found that PtNi-MoC / GN had the best electrochemical performance among the molybdenum-based catalysts supported by PtNi alloy. In order to continue to explore the reasons for its high performance, PtNi / GN was also electrochemically tested under the same conditions. The results showed that the current density of PtNi / GN (2.39 mA cm -2 ) is lower than PtNi-MoC / GN (2.89mAcm -2 ), which proves that the synergy between PtNi and MoC is the reason why PtNi-MoC / GN has excellent electrochemical performance.

[0129] (4) The electrochemical performance of the electrocatalysts prepared in Example 6, Example 7 and Comparative Example 1 was tested in a 0.1 M HClO4 solution at 1600 rpm under saturated H2 conditions. The results are as follows: Figure 5 As shown by Figure 5 It can be seen that Pt-MoNiN / GN has the best electrochemical performance among the Pt-loaded molybdenum-based catalysts. In order to further explore the reasons for its high performance, Pt-MoN / GN and Pt-NiN / GN were also electrochemically tested under the same conditions. The results showed that the current density of Pt-MoN / GN (1.98 mA cm -2 ) and the current density of Pt-NiN / GN (1.31 mA cm -2 ) are lower than those of Pt-MoNiN / GN, which proves that the synergy between Pt and MoNiN is the reason why Pt-MoNiN / GN has excellent electrochemical performance.

[0130] (5) The electrochemical performance of the fuel cell assembled with the electrocatalysts prepared in Example 1 and Example 7 was tested in a 0.1 M HClO4 solution containing 1000 ppm CO in H2. The results are as follows: Figure 6 As shown by Figure 6 It can be seen that PtNi-MoC / GN and Pt-MoNiN / GN have excellent electrochemical properties as shown above. We continued to conduct electrochemical tests on the two in H2 containing 1000ppm CO to explore their CO resistance. Finally, we found that the current density of Pt-MoNiN / GN only decayed by 5.9%, while the current density of PtNi-MoC / GN decayed by 17.6%, proving that Pt-MoNiN / GN has a CO resistance far superior to PtNi-MoC / GN.

[0131] (6) The fuel cell assembled with the electrocatalyst prepared in Example 1 was tested for fuel performance at 80°C, 0.1 bar back pressure, H2-O2 and 10 ppm CO / H2-O2 gas. The results are as follows: Figure 7 As shown by Figure 7 It can be seen that the power density of PtNi-MoC / GN under H2-O2 gas reaches 1.99 W cm -2 , and its power density can still be maintained at 1.24W cm in a gas containing 10ppmCO / H2-O2 -2 , proving that PtNi-MoC / GN not only has excellent fuel cell performance but also has excellent CO resistance.

[0132] (8) The fuel cell assembled with the electrocatalyst prepared in Example 7 was tested for fuel performance at 80°C, 0.1 bar back pressure, H2-O2 and 10 ppm CO / H2-O2 gas. The results are as follows: Figure 8 As shown by Figure 8 It can be seen that the power density of Pt-MoNiN / GN under H2-O2 gas is 1.73 W cm -2 , weaker than PtNi-MoC / GN (1.99 W cm -2 ).

[0133] Although the present invention has been disclosed as above in the preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing a molybdenum-based low-platinum electrocatalyst, characterized in that: include: (1) dissolving a carbon source in an organic solvent, then adding a molybdenum source or a mixture of a molybdenum source and a nickel source, and stirring until the carbon source is completely dissolved to obtain a molybdenum salt solution or a solution of a molybdenum salt and a nickel source; The carbon source is reduced graphene oxide; the molybdenum source is ammonium molybdate, sodium molybdate, phosphomolybdic acid, zinc molybdate or magnesium molybdate; the nickel source is nickel chloride, nickel sulfate or nickel nitrate; (2) Continue to add nitrogen-containing ligands and perform ultrasonic treatment until uniform mixing; The nitrogen-containing ligand is o-phenanthroline; (3) placing the uniform mixed solution obtained in (2) into a stainless steel reactor for reaction to obtain a carbon / molybdenum nitride precursor or a carbon / molybdenum nitride nickel precursor; Reaction temperature 120℃~150℃, time 10h~20h; (4) heat treating the carbon / molybdenum nitride precursor or the carbon / molybdenum nickel nitride precursor in a nitrogen atmosphere, an argon atmosphere containing a phosphorus source, or an ammonia atmosphere to obtain a molybdenum-containing compound; Heat treatment conditions are: heating to 800~1000℃ at a rate of 10℃ / min, keeping temperature for 1.5~3.5h; (5) mixing a platinum source and a transition metal source and subjecting the mixture to a high temperature sintering treatment to obtain a platinum-containing alloy material; (6) The platinum-containing alloy material is loaded on the molybdenum-containing compound by a reduction method to obtain a molybdenum-based low-platinum electrocatalyst with a Pt loading of 3%.

2. The preparation method according to claim 1, characterized in that: (1) The mass ratio of the carbon source to the organic solvent is 1:(1-20), the mass ratio of the molybdenum source to the carbon source is 1:(50-100); the molar ratio of the molybdenum source to the nickel source is 1:(1-2.5).

3. The preparation method according to claim 1, characterized in that: (2) The mass ratio of nitrogen-containing ligand to molybdenum source is 1:(2~10).

4. The preparation method according to claim 1, characterized in that: (4) The phosphorus source is NaH2PO2 or NH4H2PO2.

5. The preparation method according to claim 1, characterized in that: (5) The platinum source is chloroplatinic acid, ammonium platinate or sodium chloroplatinate (IV); the transition metal source is a mixture of one or more of nickel chloride, nickel nitrate, ferric acetylacetonate, ferric chloride, cobalt nitrate and cobalt chloride.

6. The preparation method according to claim 1, characterized in that: (6) The reduction method is ethylene glycol reduction, sodium borohydride reduction, hydrogen reduction or photoreduction.

7. A molybdenum-based low-platinum electrocatalyst obtained by the preparation method according to any one of claims 1 to 6.

8. An anode working electrode of a proton exchange membrane fuel cell, characterized in that: The working electrode is made of the molybdenum-based low-platinum electrocatalyst described in claim 7.

9. A proton exchange membrane fuel cell, characterized in that: The proton exchange membrane fuel cell comprises the anode working electrode as claimed in claim 8.

Images