Preparation method of boron / sulfur co-doped high-entropy alloy catalyst
By using the method of combining constant current pulse technology and cyclic voltammetry in the electrocatalyst, boron/sulfur co-doped high-entropy alloy catalysts were prepared, which solved the problem of insufficient catalytic activity and selectivity of the existing electrocatalysts, and achieved an efficient urea process for synthesis of CO2 and N2.
Patent Information
- Application Number
- CN202510527097.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-24
- Publication Date
- 2025-06-13
AI Technical Summary
The existing electrocatalysts have insufficient catalytic activity and selectivity in the synthesis of urea with CO2 and N2, resulting in low yield and low Faraday efficiency, limiting their practical application.
The constant current pulse technology and cyclic voltammetry technology are used to prepare boron/sulfur co-doped high-entropy alloy catalysts, and the performance of the catalyst is improved through electroplating and electrochemical activation processes.
High Faraday efficiency and urea yield were achieved, which was specifically manifested as when the applied bias voltage was -0.10V, the urea yield could reach 251.67μg cm-2h-1, and the Faraday efficiency could reach 91.61%.
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Figure CN120138683A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of electrocatalysts and relates to a preparation method of a boron / sulfur co-doped high-entropy alloy catalyst. Background Art
[0002] Urea is an important chemical fertilizer and industrial raw material. The traditional production process includes two steps: producing synthetic ammonia by the Haber-Bosch method and producing urea by the Bosch-Meiser method. Both of these two steps have high energy consumption and large CO 2 emissions. In recent years, electrocatalytic N 2 and CO 2 direct synthesis of urea has received extensive attention due to its green, low-carbon, and sustainable characteristics.
[0003] Jiao Dongxu et al. designed a MoP-(101) surface catalyst with a urea production rate of 12.4 μg h -1 mg -1 and a Faraday efficiency of 36.5%. Zhang Guangjin et al. designed a nano-InOOH catalyst containing Lewis acid-base pairs with a urea production rate of 6.85 mmol h -1 g -1 and a Faraday efficiency of 20.97%. Wang Shuangyin et al. designed a Zn-Mn dual-atom catalyst with axial chlorine coordination with a urea production rate of 4.0 mmol h -1 g -1 and a Faraday efficiency of 28.7%. Lai Jianping et al. designed a liquid alloy Ga 79 Cu 11 Mo 10 @C catalyst with a urea production rate of 28.25 mmol h -1 g -1 and a Faraday efficiency of 60.60%.
[0004] The above catalysts all have the defects of low urea production rate and low Faraday efficiency, which limit their practical applications. Therefore, there is an urgent need to develop highly efficient electrocatalysts.
[0005] High-entropy alloys are one of the most promising functional materials in the field of electrocatalysis. The complexity and tunability of the components enable high-entropy alloys to obtain optimal catalytic performance. Doping with non-metallic elements can further improve the catalytic activity, product selectivity, and stability of high-entropy alloys.
[0006] The present invention provides a preparation method of a boron / sulfur co-doped high-entropy alloy catalyst to improve the catalytic activity and urea selectivity for the synthesis of urea from electrocatalytic CO 2 and N 2 . Summary of the Invention
[0007] The present invention adopts constant current pulse technology in combination with cyclic voltammetry technology to prepare a boron / sulfur co-doped high entropy alloy catalyst. The method has the advantages of simple process, low cost, short cycle, etc.
[0008] The objective of the present invention is achieved through the following technical solutions:
[0009] (1) dissolving five, six or seven of manganese salt, iron salt, cobalt salt, nickel salt, zinc salt, copper salt and molybdate in water, adding boric acid and thiourea, stirring and mixing thoroughly, and adjusting the pH value of the solution to obtain a stable electroplating solution;
[0010] (2) Using nickel foam as cathode and platinum sheet or carbon sheet as anode, constant current pulse technology is used to electroplate boron / sulfur co-doped high entropy alloy;
[0011] (3) The prepared boron / sulfur co-doped high entropy alloy is electrochemically activated using cyclic voltammetry technology to obtain a boron / sulfur co-doped high entropy alloy catalyst.
[0012] In step (1), the manganese salt includes one or more of manganese nitrate, manganese chloride, and manganese sulfate; the iron salt includes one or more of ferric nitrate, ferric chloride, ferric sulfate, and ferrous sulfate; the cobalt salt includes one or more of cobalt nitrate, cobalt chloride, and cobalt sulfate; the nickel salt includes one or more of nickel nitrate, nickel chloride, and nickel sulfate; the zinc salt is one or more of zinc chloride and zinc nitrate; the copper salt includes one or more of copper nitrate, copper chloride, or copper sulfate; and the molybdate includes one or more of sodium molybdate and potassium molybdate.
[0013] In step (1), the molar ratio of manganese salt to cobalt salt is preferably 1-10:1; the molar ratio of iron salt to cobalt salt is 1-5:1; the molar ratio of nickel salt to cobalt salt is 1-5:1; the molar ratio of zinc salt to copper salt is 100-150:1; the molar ratio of cobalt salt to molybdenum salt is 5-10:1; the molar ratio of molybdenum salt to zinc salt is 0.1-1:1; the molar ratio of copper salt to boric acid is 0.2-2:1; and the molar ratio of boric acid to thiourea is 0.1-1:1.
[0014] In step (1), the pH value of the electroplating solution is adjusted to 3-7 with aqueous ammonia.
[0015] In step (2), during the electroplating process, the current density of the constant current pulse is 0.1 to 4 Acm -2 , the current duty cycle is 40% to 90%, the plating solution temperature is 40 to 80°C, the stirring speed is 200 to 500 rpm, and the electroplating time is 5 min to 50 min.
[0016] In step (3), the electrochemical activation process adopts cyclic voltammetry technology, the scanning potential range is 0.10 to -1.25 V relative to the reversible hydrogen electrode, and the scanning rate is 100 to 150 mV s -1 , and the number of cycles is 100 to 150 times.
[0017] The boron / sulfur co-doped high-entropy alloy catalyst prepared by the present invention is applied to the electrocatalytic synthesis of urea from CO 2 and N 2 , and has high Faraday efficiency and yield. Description of the Drawings
[0018] Figure 1 are the urea yield and Faraday efficiency of the boron / sulfur co-doped high-entropy alloy catalyst at an applied bias voltage of -0.05 to -0.20 V. Detailed Embodiments
[0019] To clearly explain the technical solution, innovative points and advantages of the present invention, the present invention will be further described in detail below with reference to specific implementation cases. It should be particularly noted that the following embodiments are only typical representatives of the present invention and are used to help understand the technical features and implementation methods of the present invention. Their specific parameters should not be construed as limitations on the present invention. Any reasonable modification or equivalent replacement based on the technical concept of the present invention, as long as it does not depart from the essence and protection scope of the present invention, shall be regarded as being included within the scope of the claims of the present invention.
[0020] The raw materials used in the following detailed embodiments are all purchased from the market.
[0021] Example 1
[0022] Dissolve 2.94 g of Na 3 C 6 H 5 O 7 ·2H 2 O, 1.10 g of Mn(NO 3 ) 2 , 1.82 g of Co(NO 3 ) 2 ·6H 2 O, 1.97 g of NiCl 2 ·6H 2 O, 1.02 g of ZnCl 2 , 0.017 g of CuCl 2 ·2H 2 O, 0.47 g of Na 2 MoO 4 ·2H 2 O, 0.03 g of H 3 BO 3 , 0.05 g of CH4 N 2 S was dissolved in 25 ml of water. After being fully stirred and dissolved, the pH value of the electrolyte was adjusted to 6 with concentrated ammonia water. Using the constant current pulse technique, nickel foam was used as the cathode and a platinum plate electrode was used as the anode. The pulsed current density was set to 2 A cm -2 ², and electroplating was carried out for 20 min at a current duty cycle of 40%, the bath temperature was 50 °C, and the stirring speed was 300 rpm.
[0023] The prepared boron / sulfur co-doped high-entropy alloy was electrochemically activated by cyclic voltammetry technology to obtain a boron / sulfur co-doped high-entropy alloy catalyst. The activation process was carried out in an H-type electrolytic cell. Using a three-electrode system, the boron / sulfur co-doped high-entropy alloy was used as the working electrode, the platinum plate electrode was used as the counter electrode, and the saturated Ag / AgCl electrode was used as the reference electrode. In 0.5 M KHCO 3 the electrolyte was purged with a CO 2 / N 2 mixed gas for 30 min. Then a CO 2 / N 2 mixed gas was introduced, and the flow rates were each 10 mL min -1 ⁻¹; the scanning potential window of cyclic voltammetry was 0.55 to -0.65 V relative to the reversible hydrogen electrode, the scanning rate was 100 mV s -1 ⁻¹, and the number of cycles was 100 times to obtain a boron / sulfur co-doped high-entropy alloy catalyst.
[0024] The reaction of electrocatalytic reduction of N 2 ₂ and CO 2 ₂ to urea was carried out in the above three-electrode system. Figure 1 The urea yield and Faraday efficiency were when the applied bias voltage was -0.05 to -0.20 V relative to the reversible hydrogen electrode. When the applied bias voltage was -0.10 V, the catalyst showed the optimal catalytic performance, and the urea yield could reach 251.67 μg cm -2 ⁻² h -1 ⁻¹, and the Faraday efficiency could reach 91.61%.
Claims
1. A method for preparing a boron / sulfur co-doped high entropy alloy catalyst, characterized in that: (1) dissolving five, six or seven of manganese salt, iron salt, cobalt salt, nickel salt, zinc salt, copper salt and molybdate in water, adding boric acid and thiourea, stirring and mixing thoroughly, and adjusting the pH value of the solution to obtain a stable electroplating solution; (2) Using nickel foam as cathode and platinum sheet or carbon sheet as anode, constant current pulse technology is used to electroplate boron / sulfur co-doped high entropy alloy; (3) The prepared boron / sulfur co-doped high entropy alloy is electrochemically activated using cyclic voltammetry technology to obtain a boron / sulfur co-doped high entropy alloy catalyst.
2. The method for preparing a boron / sulfur co-doped high entropy alloy catalyst according to claim 1, characterized in that: The manganese salt includes one or more of manganese nitrate, manganese chloride, and manganese sulfate; the iron salt includes one or more of ferric nitrate, ferric chloride, ferric sulfate, and ferrous sulfate; the cobalt salt includes one or more of cobalt nitrate, cobalt chloride, and cobalt sulfate; the nickel salt includes one or more of nickel nitrate, nickel chloride, and nickel sulfate; the zinc salt is one or more of zinc chloride and zinc nitrate; the copper salt includes one or more of copper nitrate, copper chloride, or copper sulfate; and the molybdate includes one or more of sodium molybdate and potassium molybdate.
3. The method for preparing a boron / sulfur co-doped high entropy alloy catalyst according to claim 1, characterized in that: The molar ratio of manganese salt to cobalt salt is 1-10:1; the molar ratio of iron salt to cobalt salt is 1-5:1; the molar ratio of nickel salt to cobalt salt is 1-5:1; the molar ratio of zinc salt to copper salt is 100-150:1; the molar ratio of cobalt salt to molybdenum salt is 5-10:1; the molar ratio of molybdenum salt to zinc salt is 0.1-1:1; the molar ratio of copper salt to boric acid is 0.2-2:1; and the molar ratio of boric acid to thiourea is 0.1-1:
1.
4. The method for preparing a boron / sulfur co-doped high entropy alloy catalyst according to claim 1, characterized in that: The pH value of the plating solution is adjusted to 3-7 with ammonia water.
5. The method for preparing a boron / sulfur co-doped high entropy alloy catalyst according to claim 1, characterized in that: During the electroplating process, the current density of the constant current pulse is 0.1~4A cm -2 .
6. The method for preparing a boron / sulfur co-doped high entropy alloy catalyst according to claim 1, characterized in that: During the electroplating process, the current duty cycle is 40% to 90%.
7. The method for preparing a boron / sulfur co-doped high entropy alloy catalyst according to claim 1, characterized in that: During the electroplating process, the plating solution temperature is 40-80°C and the stirring speed is 200-500rpm.
8. The method for preparing a boron / sulfur co-doped high entropy alloy catalyst according to claim 1, characterized in that: The electroplating time is 5 minutes to 50 minutes.
9. The method for preparing a boron / sulfur co-doped high entropy alloy catalyst according to claim 1, characterized in that: The electrochemical activation process used cyclic voltammetry technology with a scanning potential range of 0.10 to -1.25 V relative to the reversible hydrogen electrode and a scanning rate of 100 to 150 mV s -1 , the number of cycles is 100 to 150 times.
10. The method for preparing a boron / sulfur co-doped high entropy alloy catalyst according to claim 1, characterized in that: The catalyst is used for the electrocatalytic synthesis of urea from CO2 and N2 and has high Faradaic efficiency and yield.