Preparation method of nitrogen and sulfur co-doped carbon nanotube coated nickel nanoparticle oxygen evolution electrocatalyst
Through the preparation method of oxygen evolution electrocatalyst coated nickel nanoparticles by co-doped nitrogen and sulfur, the problems of low oxygen evolution reaction efficiency and complex, expensive and poor stability in hydrogen production in water decomposition are solved, and high efficiency, low cost and stable catalyst performance are achieved.
Patent Information
- Application Number
- CN202510266264.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-07
- Publication Date
- 2025-05-09
AI Technical Summary
The existing water decomposition hydrogen production process is limited by oxygen evolution reaction (OER), and high overpotentials are required, resulting in low efficiency and energy conversion rates, and the commercial OER catalyst preparation process is complex, expensive and low stability.
The preparation method of oxygen evolution electrocatalyst coated nickel nanoparticles with nitrogen and sulfur co-doped carbon nanotubes was used to prepare N,S-CNT@Ni composite materials through three steps: high-temperature pyrolysis, pickling and hydrothermal heat.
The catalyst preparation process is simplified, production costs are reduced, the stability and performance of the catalyst are improved, and oxygen evolution reaction can be carried out at a lower loading voltage, saving electricity.
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Figure CN119956416A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of hydrogen energy production, and in particular to a method for preparing an oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles. Background Art
[0002] The water splitting reaction provides a promising method for storing intermittent renewable energy in the form of hydrogen fuel. However, the production of hydrogen by water splitting is limited by its oxidation half-reaction, namely the oxygen evolution reaction (OER). Due to the participation of the complex and continuous four-electron and proton transfer process of OER, it is kinetically slow and requires a large overpotential for the water splitting reaction to proceed smoothly, which seriously reduces the efficiency and energy conversion rate of water splitting hydrogen production. The addition of an oxygen evolution catalyst can effectively reduce the overpotential of the oxygen evolution reaction, allowing the oxygen evolution reaction to proceed at a lower loading voltage, thereby achieving the effect of saving electricity.
[0003] Transition metal-based materials are a class of non-precious metal oxygen evolution catalyst materials with great potential to replace precious metal-based catalysts. However, although these OER catalysts have been significantly improved, they are still not comparable to noble metal-based catalysts. The conductivity of these catalysts cannot meet the requirements of OER catalysts. Usually, researchers use conductive carbon-based materials as substrates for particles with catalytic active sites, such as CNT, graphene, activated carbon, etc., to improve the overall conductivity. Anchoring or embedding active nanoparticles on / in heteroatom-doped carbon can be a promising method. Currently, the best oxygen evolution catalysts are mainly precious metal-based catalysts, such as RuO2, IrO2, etc. However, they have the disadvantages of high price, scarcity and poor durability, which hinder their widespread commercial application. Therefore, studying low-cost, abundant and efficient OER catalysts is of great practical significance to accelerate the development of the overall water splitting green energy conversion system. Current research shows that
[0004] Therefore, in order to address the problems of complex preparation process, high price and low stability of the above-mentioned commercial OER catalysts, a method for preparing an oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles can be designed. Summary of the invention
[0005] In order to overcome the problems of complex preparation process, high price and low stability of commercial OER catalysts.
[0006] The technical scheme of the present invention is: a method for preparing an oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles. The method uses nickel nitrate hexahydrate and dinitrile diamine as precursors, adopts a high-temperature pyrolysis method to synthesize Ni / N-CNT@Ni, corrodes the metal nickel not combined with the carbon nanotubes by acid washing, and then uses a hydrothermal method to use thiourea as an S source to finally prepare a N,S-CNT@Ni composite material.
[0007] As a preference, the specific steps are as follows:
[0008] Step 1: Mix nickel nitrate hexahydrate, dinitrile diamine and ethanol, and grind the mixture thoroughly in a mortar until the ethanol is completely evaporated;
[0009] Step 2: The ground mixture was vacuum dried, and then the mixed powder was placed in a tube furnace and heated at 5-10 °C min under an argon atmosphere. -1 The temperature is heated to a preset temperature at a heating rate and kept at this temperature to obtain N-CNT@Ni black powder;
[0010] Step 3: Then, the N-CNT@Ni powder is immersed in a hydrogen chloride solution to corrode the large particles of Ni that are not combined with the carbon nanotubes, and then the powder is vacuum filtered and washed to neutrality, and then placed in a vacuum drying oven for drying to obtain the N-CNT@Ni product;
[0011] Step 4: put thiourea into deionized water and ultrasonicate it in an ultrasonic cleaner for 30 minutes, then add N-CNT@N powder and ultrasonicate it for 30 minutes;
[0012] Step 5: Pour the solution into a 100 mL polytetrafluoroethylene liner, heat at 180°C for 8-24 hours, centrifuge, and wash the solution with deionized water;
[0013] Step 6: Finally, freeze-drying is performed to obtain N,S-CNT@Ni composite material.
[0014] Preferably, in step 1, the mass ratio of nickel nitrate hexahydrate to dinitrile diamine is 3 to 5:4.
[0015] Preferably, the vacuum drying temperature in step 2 is 40° C., the time is 12 h, the preset temperature is 600-900° C., and the insulation time is 30-60 min.
[0016] Preferably, in step three, the concentration of the hydrogen chloride solution is 1-3 mol / L, the soaking time is 12 h, and the vacuum drying temperature is 60° C. and the time is 12 h.
[0017] Preferably, in step 4, the usage ratio of thiourea, deionized water and N-CNT@N powder is 8-12 mg: 1 ml: 2 mg.
[0018] Preferably, in step five, the centrifugal speed is 6000 rpm, and the number of times the deionized water cleaning solution is used is 3 times.
[0019] Preferably, the freeze-drying time in step six is 12 hours.
[0020] The beneficial effects of the present invention are as follows: it involves only three steps of high-temperature pyrolysis, acid washing and hydrothermal treatment, is simple to operate, does not require any equipment, is easy to mass produce, has a simple preparation process, and uses cheap and readily available raw materials, thereby reducing the production cost of the catalyst. Experiments have confirmed that after 12 hours of time-current testing, the performance of the catalyst remains almost unchanged, and the stability is good. High-temperature pyrolysis can effectively promote the structural transformation of the catalyst material, thereby improving its activity and selectivity. After high-temperature treatment, impurities and inactive components in the material are removed, thereby improving the purity and performance of the catalyst. Acid washing removes impurities on the surface of the material through a specific acid solution, thereby further optimizing its catalytic performance. Hydrothermal treatment can promote the optimization of the internal pore structure of the catalyst, increase the number of active sites, and thereby enhance the catalytic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 The process flow chart of the preparation method of the oxygen evolution electrocatalyst of the nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles of the present invention is shown;
[0022] Figure 2 Shown is a field emission scanning electron micrograph of N,S-CNT@Ni;
[0023] Figure 3 Shown is the projection electron micrograph of N,S-CNT@Ni (50nm);
[0024] Figure 4 Shown is the projection electron micrograph of N,S-CNT@Ni (10nm);
[0025] Figure 5 Shown are the LSV test graphs of Example 1, Comparative Example 1 and Comparative Example 2;
[0026] Figure 6 The time-current test curves of Example 1 and Comparative Example 2 are shown. DETAILED DESCRIPTION
[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.
[0028] See also Figure 1-6The present invention provides a method for preparing an oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles. The method uses nickel nitrate hexahydrate and dinitrile diamine as precursors, and adopts a high-temperature pyrolysis method to synthesize Ni / N-CNT@Ni. The metal nickel not combined with the carbon nanotubes is corroded by acid washing, and then a hydrothermal method is used to use thiourea as an S source to finally prepare a N,S-CNT@Ni composite material.
[0029] As a preference, the specific steps are as follows:
[0030] Step 1: Mix nickel nitrate hexahydrate, dinitrile diamine and ethanol, and grind the mixture thoroughly in a mortar until the ethanol is completely evaporated;
[0031] Step 2: The ground mixture was vacuum dried, and then the mixed powder was placed in a tube furnace and heated at 5-10 °C min under an argon atmosphere. -1 The temperature is heated to a preset temperature at a heating rate and kept at this temperature to obtain N-CNT@Ni black powder;
[0032] Step 3: Then, the N-CNT@Ni powder is immersed in a hydrogen chloride solution to corrode the large particles of Ni that are not combined with the carbon nanotubes, and then the powder is vacuum filtered and washed to neutrality, and then placed in a vacuum drying oven for drying to obtain the N-CNT@Ni product;
[0033] Step 4: put thiourea into deionized water and ultrasonicate it in an ultrasonic cleaner for 30 minutes, then add N-CNT@N powder and ultrasonicate it for 30 minutes;
[0034] Step 5: Pour the solution into a 100 mL polytetrafluoroethylene liner, heat at 180°C for 8-24 hours, centrifuge, and wash the solution with deionized water;
[0035] Step 6: Finally, freeze-drying is performed to obtain N,S-CNT@Ni composite material.
[0036] Preferably, in step 1, the mass ratio of nickel nitrate hexahydrate to dinitrile diamine is 3 to 5:4.
[0037] Preferably, the vacuum drying temperature in step 2 is 40° C., the time is 12 h, the preset temperature is 600-900° C., and the insulation time is 30-60 min.
[0038] Preferably, in step three, the concentration of the hydrogen chloride solution is 1-3 mol / L, the soaking time is 12 h, and the vacuum drying temperature is 60° C. and the time is 12 h.
[0039] Preferably, in step 4, the usage ratio of thiourea, deionized water and N-CNT@N powder is 8-12 mg: 1 ml: 2 mg.
[0040] Preferably, in step five, the centrifugal speed is 6000 rpm, and the number of times the deionized water cleaning solution is used is 3 times.
[0041] Preferably, the freeze-drying time in step six is 12 hours.
[0042] As used herein, the term "dinitrile diamine" is abbreviated as "DCDA".
[0043] As used herein, the term "nickel nitrate hexahydrate" is abbreviated as "Ni(NO 3 ) 2 6H 2 O”.
[0044] As used herein, the term "hydrogen chloride" has the chemical formula "HCl".
[0045] Example 1
[0046] Will Ni(NO 3 ) 2 6H 2 O 200 mg, DCDA 200 mg and a small amount of ethanol were mixed and the mixture was thoroughly ground in a mortar until the ethanol was completely evaporated. The ground mixture was dried in vacuum at 40 °C for 12 h, and then the mixed powder was placed in a tube furnace and heated at 5 °C min under an argon atmosphere. -1 The mixture was heated to 900°C at a heating rate of 1000 °C and kept warm for 30 min to obtain N-CNT@Ni black powder. The N-CNT@Ni powder was then immersed in 1M HCl for 12 h to corrode the large particles of Ni that were not combined with the carbon nanotubes. The mixture was then vacuum filtered and cleaned to neutrality and dried in a vacuum drying oven at 60°C for 12 h to obtain N-CNT@Ni product. 500 mg of thiourea was placed in 50 ml of deionized water and ultrasonicated in an ultrasonic cleaner for 30 min. Then 100 mg of N-CNT@N powder was added and ultrasonicated for 30 min. The solution was poured into a 100 mL polytetrafluoroethylene liner and hydroheated at 180°C for 12 h. The solution was then centrifuged at 6000 rpm and washed 3 times with deionized water. The solution was then freeze-dried for 12 h to obtain N,S-CNT@Ni composite material.
[0047] Comparative Example 1: Preparation of N-CNT@Ni
[0048] Will Ni(NO 3 ) 2 6H 2O 200 mg, DCDA 200 mg and ethanol 2 mL were mixed and the mixture was thoroughly ground with a pestle and mortar until the ethanol was completely evaporated. The ground mixture was dried under vacuum at 40 °C for 12 h, and then the mixed powder was placed in a tube furnace and heated at 5 °C min under an argon atmosphere. -1 The mixture was heated to 900°C at a heating rate and kept warm for 30 minutes to obtain N-CNT@Ni black powder, which was then immersed in 1M HCl for 12 hours to corrode large particles of Ni that were not combined with carbon nanotubes, and then vacuum filtered and cleaned until neutral, and dried in a vacuum drying oven at 60°C for 12 hours to obtain the final product of N-CNT@Ni.
[0049] Comparative Example 2: Commercial RuO 2
[0050] Experimental example
[0051] (1) Scanning electron microscopy was used to observe and analyze the surface morphology and microstructure of the material. SEM scans the sample surface and uses the signal generated by the interaction between the electron beam and the sample to obtain an image. Transmission electron microscopy (TEM) was used to observe and analyze the microstructure of N,S-CNT@Ni. The field emission scanning electron micrograph of N,S-CNT@Ni is shown in Figure 2. Figure 2 , projection electron micrographs such as Figure 3 and Figure 4 .
[0052] (2) Conduct polarization curve measurement experiments
[0053] The experimental results of Example 1, Comparative Example 1 and Comparative Example 2 are as follows: Figure 5 : At 100mA cm -2 Example 1 has an overpotential of 560 mV at the current density, which is better than Comparative Example 1 (lower, not shown during the test) and also better than Comparative Example 2 (noble metal RUO 2 , 600mV);
[0054] (3) By controlling the current density and continuously applying power for a period of time, the N,S-CNT@Ni and RUO 2 The changes in key parameters such as potential and current density are used to evaluate its stability.
[0055] from Figure 6 It can be seen that after 12 hours of time-current test, the performance of N,S-CNT@Ni has hardly changed, and its stability is better than that of commercial noble metal RUO 2 Better, commercial noble metal RUO 2 Decreased by 20%.
[0056] The above steps only involve three steps: high-temperature pyrolysis, acid washing and hydrothermal treatment. The preparation process is simple and the raw materials used are all cheap and readily available chemicals, which reduces the production cost of the catalyst. Experiments have confirmed that after 12 hours of time-current testing, the performance of the catalyst has hardly changed and has good stability, thereby solving the problems of complex preparation process, high price and low stability of commercial OER catalysts.
[0057] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the spirit of the present invention.
Claims
1. A method for preparing an oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles, characterized in that: This method uses nickel nitrate hexahydrate and dinitrile diamine as precursors, and adopts high-temperature pyrolysis to synthesize Ni / N-CNT@Ni. The metal nickel that is not combined with carbon nanotubes is corroded away by acid washing, and then a hydrothermal method is used to use thiourea as the S source to finally prepare the N,S-CNT@Ni composite material.
2. The method for preparing the oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles according to claim 1, characterized in that: The specific steps are as follows: Step 1: Mix nickel nitrate hexahydrate, dinitrile diamine and ethanol, and grind the mixture thoroughly in a mortar until the ethanol is completely evaporated; Step 2: The ground mixture was vacuum dried, and then the mixed powder was placed in a tube furnace and heated at 5-10 °C min under an argon atmosphere. -1 The temperature is heated to a preset temperature at a heating rate and kept at this temperature to obtain N-CNT@Ni black powder; Step 3: Then, the N-CNT@Ni powder is immersed in a hydrogen chloride solution to corrode the large particles of Ni that are not combined with the carbon nanotubes, and then the powder is vacuum filtered and washed to neutrality, and then placed in a vacuum drying oven for drying to obtain the N-CNT@Ni product; Step 4: put thiourea into deionized water and ultrasonicate it in an ultrasonic cleaner for 30 minutes, then add N-CNT@N powder and ultrasonicate it for 30 minutes; Step 5: Pour the solution into a 100 mL polytetrafluoroethylene liner, heat at 180°C for 8-24 hours, centrifuge, and wash the solution with deionized water; Step 6: Finally, freeze-drying is performed to obtain N,S-CNT@Ni composite material.
3. The method for preparing the oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles according to claim 2, characterized in that: In step 1, the mass ratio of nickel nitrate hexahydrate to dinitrile diamine is 3 to 5:
4.
4. The method for preparing the oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles according to claim 2, characterized in that: In step 2, the vacuum drying temperature is 40° C. and the time is 12 h. The preset temperature is 600-900° C. and the insulation time is 30-60 min.
5. The method for preparing the oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles according to claim 2, characterized in that: In step 3, the concentration of the hydrogen chloride solution is 1-3 mol / L, the soaking time is 12 h, and the vacuum drying temperature is 60° C. and the time is 12 h.
6. The method for preparing the oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles according to claim 2, characterized in that: In step 4, the dosage ratio of thiourea, deionized water and N-CNT@N powder is 8-12 mg: 1 ml: 2 mg.
7. The method for preparing the oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles according to claim 2, characterized in that: In step 5, the centrifugal speed is 6000 rpm, and the number of times the deionized water cleaning solution is 3 times.
8. The method for preparing the oxygen evolution electrocatalyst of nitrogen and sulfur co-doped carbon nanotubes coated with nickel nanoparticles according to claim 2, characterized in that: The freeze-drying time in step six is 12 h.