Foamed nickel and NiCo2S4 composite low-platinum catalyst and preparation method thereof
By supporting a composite catalyst of NiCo2S4 and low platinum on nickel foam, the problem of insufficient activity of the anode catalyst of traditional methanol fuel cell is solved, and higher catalytic activity and stability are achieved.
Patent Information
- Application Number
- CN202510062504.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-15
- Publication Date
- 2025-04-25
AI Technical Summary
The catalytic activity of the anode catalyst in traditional methanol fuel cells is low, resulting in insufficient efficiency and stability of the fuel cell.
A low-platinum catalyst was used to combine foam nickel with NiCo2S4 with low platinum catalyst, and Pt@NiCo2S4/Ni foam catalyst was prepared by hydrothermal reaction and reduction reaction, and supported on foam nickel to improve catalytic activity.
It improves the catalytic activity and stability of the catalyst, enhances the activation ability of methanol electrooxidation, and effectively resists CO poisoning.
Smart Images
Figure CN119890337A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of fuel cells, and in particular relates to a foamed nickel and NiCo2S4 composite low-platinum catalyst and a preparation method and application thereof. Background Art
[0002] With the increasing importance of green and clean energy, direct methanol fuel cells (DMFC) have attracted more and more attention as a promising research hotspot. DMFC mainly consists of two half reactions: anodic oxidation and cathode reduction. Methanol anodic oxidation reaction (MOR) is the process of oxidizing CH3OH to CO2, which is characterized by a six-electron transfer reaction. The kinetic rate of this electrode reaction is slow, and the performance of the catalyst is the key factor affecting the reaction. Sulfur is abundant in source, low in cost, non-toxic after use, and environmentally friendly, which has important research significance and broad application prospects.
[0003] At present, platinum-based noble metal catalysts are the most effective and stable catalysts in the catalytic oxidation of methanol. Noble metal catalysts have high catalytic activity for MOR in DMFC, but their high cost, limited reserves, and easy CO poisoning hinder their large-scale commercial production and application. Compared with noble metal catalysts, non-noble metal catalysts have great cost advantages. Improving the catalytic performance of such materials can achieve the purpose of replacing noble metal catalysts. Therefore, it is crucial to develop low-cost, abundant, highly active, and stable non-noble metal anode electrocatalysts. Summary of the invention
[0004] To address the deficiencies in the prior art, the present invention provides a foamed nickel and NiCo2S4 composite low-platinum catalyst and a preparation method and application thereof, so as to solve the problem of low catalytic activity of anode catalysts in traditional methanol fuel cells.
[0005] The technical solution provided by the present invention is as follows:
[0006] A method for preparing a composite low-platinum catalyst of nickel foam and NiCo2S4 comprises the following steps:
[0007] 1) taking a certain amount of nickel foam, nickel salt, cobalt salt, urea and water, stirring the mixture magnetically and performing a hydrothermal reaction, collecting the precipitate by centrifugation after the reaction is completed, and drying it in a drying oven to prepare a NiCo2S4 precursor;
[0008] 2) mixing the NiCo2S4 precursor with a sodium sulfide aqueous solution and subjecting the mixture to a hydrothermal reaction to prepare a composite of NiCo2S4 and nickel foam, referred to as NiCo2S4 / Ni foam;
[0009] 3) The composite of NiCo2S4 and nickel foam is mixed with potassium chloroplatinite and a reducing agent to carry out a reduction reaction to prepare a composite low-platinum catalyst of nickel foam and NiCo2S4, which is recorded as Pt@NiCo2S4 / Ni foam.
[0010] In the above technical solution:
[0011] In step 1), nickel salt, cobalt salt and urea react to obtain a NiCo2S4 precursor;
[0012] In step 2), a NiCo2S4 precursor is mixed with a sodium sulfide aqueous solution and then subjected to a hydrothermal reaction, so as to obtain a mixture of NiCo2S4 and nickel foam;
[0013] In step 3), the composite of NiCo2S4 and nickel foam is mixed with potassium chloroplatinite and a reducing agent, and potassium chloroplatinite is reduced by the reducing agent to generate Pt, which is loaded on NiCo2S4 / Ni foam.
[0014] Specifically, in step 1):
[0015] The nickel salt is selected from any one of nickel nitrate, nickel chloride or nickel sulfate;
[0016] The cobalt salt is selected from cobalt nitrate, cobalt chloride or cobalt sulfate;
[0017] The molar ratio of nickel foam to nickel salt, cobalt salt, urea and water is (1-5):(1-5):(2-10):(3-15):(4175-20875).
[0018] Specifically, in step 1):
[0019] Magnetic stirring for 20-40 minutes;
[0020] The conditions of the hydrothermal reaction are: temperature 120-160°C, time 8-12h;
[0021] The drying temperature is: 55-70℃, and the time is 15-25h.
[0022] Specifically, in step 2), the molar ratio of NiCo2S4 precursor to sodium sulfide is (2-5):(3-7.5).
[0023] Specifically, in step 2), the conditions of the hydrothermal reaction are: temperature of 160° C. and time of 6-10 h.
[0024] Specifically, in step 3), the ratio of the composite of NiCo2S4 and nickel foam to potassium chloroplatinite and the reducing agent is (1-5):(5-10):(1-5).
[0025] Specifically, the chloroplatinite is potassium chloroplatinite or sodium chloroplatinite.
[0026] Specifically, the reducing agent is ascorbic acid or glucose.
[0027] Specifically, in step 3), the conditions for the reduction reaction are: temperature of 85° C. and time of 1 hour.
[0028] The present invention also provides a foamed nickel and NiCo2S4 composite low-platinum catalyst prepared by the above preparation method, wherein the Pt content is less than 5wt%.
[0029] Specifically, the nickel foam and NiCo2S4 composite low-platinum catalyst is in the shape of a hollow sea urchin.
[0030] Preferably, the molar ratio of the nickel salt to the cobalt salt in step 1) is 1:1; the molar ratio of the NiCo2S4 precursor to the sodium sulfide in step 2) is 2:3; and the molar ratio of the NiCo2S4 / Ni foam, the chloroplatinous salt and the reducing agent in step 3) is 1:2:1.
[0031] Preferably, the molar ratio of the nickel salt to the cobalt salt in step 1) is 1:2; the molar ratio of the NiCo2S4 precursor to the sodium sulfide in step 2) is 2:3; and the molar ratio of the NiCo2S4 / Ni foam, the chloroplatinous salt and the reducing agent in step 3) is 1:2:1.
[0032] The present invention also provides the use of a composite low-platinum catalyst of nickel foam and NiCo2S4 as an anode catalyst for a methanol fuel cell.
[0033] The beneficial effects of the present invention are:
[0034] 1) The present invention adopts nickel foam and uses nickel nitrate hexahydrate as a nickel source and cobalt nitrate hexahydrate as a cobalt source, and loads precious metal Pt and non-precious metal Ni, Co alloy particles on nickel foam by a chemical reduction method to prepare Pt@NiCo2S4 / Ni foam, which is used as an anode catalyst for a methanol fuel cell. The synergistic effect of nickel and cobalt metals can not only improve the stability of the catalyst, but also effectively improve the catalytic activity and resistance to CO poisoning of the catalyst.
[0035] 2) The addition of dual-doped metals Ni and Co enables the catalyst to activate water decomposition at a lower potential to provide adsorbed hydroxyls (OHads), which not only promotes the adsorption and dissociation of water that directly affects the catalytic reaction, but also improves the catalytic effect of Pt through electronic effects and coordination effects.
[0036] 3) The hollow structure composed of regularly arranged nanorods provides a large surface area, and the external structure of the sea urchin builds bridges between the microspheres, accelerating charge transfer and thus promoting the catalytic reaction. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 This is a scanning electron microscope image of Example 1 of the present invention.
[0038] Figure 2 This is a transmission electron microscope image of Example 1 of the present invention.
[0039] Figure 3 This is the X-ray diffraction pattern of Example 1 of the present invention.
[0040] Figure 4 The cyclic voltammetry curves of the catalyst Pt@NiCo2S4 / Ni foam and commercial Pt / C in each embodiment of the present invention in 0.5M KOH+1MCH3OH solution are shown.
[0041] Figure 5 The chronoamperometric curves are cyclic voltammetry curves of the catalyst Pt@NiCo2S4 / Ni foam and commercial Pt / C in 0.5M KOH+1MCH3OH solution in Example 1 of the present invention. DETAILED DESCRIPTION
[0042] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.
[0043] Unless otherwise specified, the test methods used in the examples are conventional methods; the materials and reagents used are commercially available unless otherwise specified. If no specific techniques or conditions are specified, the techniques or conditions described in the literature in the field or the product instructions are used.
[0044] Description of the reagents used: nickel nitrate hexahydrate is %95% pure; nickel nitrate hexahydrate is %95% pure; urea is %99% pure; nickel foam is purchased from Taobao; potassium chloroplatinite is %99.99% pure; ascorbic acid comes from Sinopharm; commercial Pt / C comes from Aladdin.
[0045] Example 1
[0046] This embodiment relates to a method for preparing a composite low-platinum catalyst of nickel foam and NiCo2S4, comprising the following steps:
[0047] 1) Mix nickel nitrate hexahydrate, cobalt nitrate hexahydrate and urea, then add water and stir at room temperature; put the pre-treated mixed solution into a hydrothermal inner tank, and gently place the nickel foam on the surface of the solution, and then react in a hydrothermal box; wherein the amount ratio of nickel nitrate hexahydrate, cobalt nitrate hexahydrate, urea and water is 4mmol:8mmol:12mmol:30mL; the amount of nickel foam is 4mmol; the solution after the above hydrothermal treatment is centrifuged and dried, washed with ethanol and deionized water for multiple times, and dried to finally obtain a NiCo2S4 precursor.
[0048] 2) Weigh the above NiCo2S4 precursor into a beaker, add sodium sulfide nonahydrate and water, stir at room temperature, and then subject the solution to a hydrothermal reaction; wherein the amount ratio of NiCo2S4 precursor, sodium sulfide nonahydrate and water is 4mmol:6mmol:50mL; centrifuge and dry the solution obtained after the above hydrothermal reaction, wash it with ethanol and deionized water for multiple times, and dry it to finally obtain NiCo2S4 / Ni foam.
[0049] 3) Weigh the above NiCo2S4 / Ni foam into a beaker, add potassium chloroplatinite, ascorbic acid and water and stir; then put the obtained solution into a round-bottom beaker for oil bath, let it stand at room temperature and then centrifuge to dry, so as to obtain Pt@NiCo2S4 / Nifoam. The usage ratio of NiCo2S4 / Ni foam, potassium chloroplatinite, ascorbic acid and water is 5mmol:10mmol:5mmol:50mL.
[0050] Among them, in step 1), the temperature of the water heating box is set to 120°C, the heating time is 8 hours, the washing is first washed with deionized water, and then centrifugal washing is performed with ethanol, the alternating washing is repeated three times, and then dried in a drying oven at 70°C for 15 hours to obtain a NiCo2S4 precursor. In step 2), the temperature of the water heating box is set to 160°C, and the heating time is 8 hours. In step 3), the temperature of the oil bath is 85°C, and the time is 1 hour.
[0051] Example 2
[0052] Refer to Example 1, the difference is that the temperature of the water heating box in step 1) is different and is set to 140°C.
[0053] Example 3
[0054] Refer to Example 1, the difference is that the temperature of the water heating box in step 1) is different and is set to 160°C.
[0055] Experimental example
[0056] The catalyst Pt@NiCo2S4 / Ni foam prepared in each example was used to test the methanol electro-oxidation performance, and the anode catalyst with the best catalytic rate was screened.
[0057] The morphology, structure and electrochemical performance of the catalyst Pt@NiCo2S4 / Ni foam obtained in Example 1 were tested. Figure 1 , 2 As shown. Figure 1 It can be seen that the interior of NiCo2S4 microspheres is composed of countless nanorods that are neatly arranged. Figure 1 , 2 It can be seen that NiCo2S4 presents a regular microspherical morphology, which is a hollow sea urchin-like hollow sphere structure.
[0058] like Figure 3 Shown is the X-ray diffraction diagram of Example 1 of the present invention.
[0059] like Figure 4 As shown, the catalyst Pt@NiCo2S4 / Ni foam obtained in step 4) of Example 1 was subjected to cyclic voltammetry test in 0.5MKOH+1M CH3OH solution, and the electrochemical active area of the catalyst Pt@NiCo2S4 / Ni foam was as high as 1186mA / mg. Compared with Pt / C (301mA / mg), it is greatly improved. The number of electrochemical active sites and surface utilization of the catalyst prepared by this method are significantly improved.
[0060] Figure 5 The cyclic voltammetry curve test of the catalyst Pt@NiCo2S4 / Ni foam obtained in Example 1 is carried out; Figure 5 It can be seen that the catalyst still maintains a certain activity after 1500s. These results show that the catalyst has good stability.
[0061] In summary, the present invention obtains the catalyst Pt@NiCo2S4 / Ni foam by nickel-cobalt dual doping. As an anode catalyst for a methanol fuel cell, the dual-doped nickel-cobalt atoms can not only increase the methanol electro-oxidation rate through coordination, but also effectively improve the catalytic activity of the catalyst.
[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing a composite low-platinum catalyst of nickel foam and NiCo2S4, characterized in that: The following steps are involved: 1) taking a certain amount of nickel foam, nickel salt, cobalt salt, urea and water, stirring the mixture magnetically and performing a hydrothermal reaction, collecting the precipitate by centrifugation after the reaction is completed, and drying it in a drying oven to prepare a NiCo2S4 precursor; 2) mixing the NiCo2S4 precursor with a sodium sulfide aqueous solution and performing a hydrothermal reaction to prepare a composite of NiCo2S4 and nickel foam; 3) The composite of NiCo2S4 and nickel foam is mixed with potassium chloroplatinite and a reducing agent to carry out a reduction reaction to prepare a composite low-platinum catalyst of nickel foam and NiCo2S4.
2. The method for preparing the composite low-platinum catalyst of nickel foam and NiCo2S4 according to claim 1, characterized in that: In step 1): The nickel salt is selected from any one of nickel nitrate, nickel chloride or nickel sulfate; The cobalt salt is selected from cobalt nitrate, cobalt chloride or cobalt sulfate; The molar ratio of nickel foam to nickel salt, cobalt salt, urea and water is (1-5):(1-5):(2-10):(3-15):(4175-20875).
3. The method for preparing the composite low-platinum catalyst of nickel foam and NiCo2S4 according to claim 1, characterized in that: In step 1): The conditions of the hydrothermal reaction are: temperature 120-160°C, time 8-12h; The drying temperature is: 55-70℃, and the time is 15-25h.
4. The method for preparing the composite low-platinum catalyst of nickel foam and NiCo2S4 according to claim 1, characterized in that: In step 2), the molar ratio of NiCo2S4 precursor to sodium sulfide is (2-5):(3-7.5).
5. The method for preparing the composite low-platinum catalyst of nickel foam and NiCo2S4 according to claim 1, characterized in that: In step 2), the conditions of the hydrothermal reaction are: temperature of 160-200° C. and time of 6-10 h.
6. The method for preparing the composite low-platinum catalyst of nickel foam and NiCo2S4 according to claim 1, characterized in that: In step 3): The dosage ratio of the composite of NiCo2S4 and nickel foam to potassium chloroplatinite and the reducing agent is (1-5):(5-10):(1-5); The chloroplatinite is potassium chloroplatinite or sodium chloroplatinite; The reducing agent is ascorbic acid or glucose.
7. The method for preparing the composite low-platinum catalyst of nickel foam and NiCo2S4 according to claim 1, characterized in that: In step 3), the reduction reaction conditions are: temperature of 85-105° C. and time of 1-2 hours.
8. A foamed nickel and NiCo2S4 composite low-platinum catalyst prepared according to the preparation method according to any one of claims 1 to 7, characterized in that: The Pt content is less than 5 wt%.
9. The nickel foam and NiCo2S4 composite low-platinum catalyst according to claim 8, characterized in that: It is hollow and shaped like a sea urchin.
10. An application of the nickel foam and NiCo2S4 composite low-platinum catalyst according to claim 8 or 9, characterized in that: As anode catalyst for methanol fuel cells.