A cobalt particle modified heteroatom doped carbon microsphere and a preparation method thereof

Abstract

This invention discloses a method for preparing cobalt-modified heteroatom-doped carbon microspheres: Co particles are used to modify heteroatom-doped carbon microspheres. 2+ Ions were complexed onto the surface of Ganoderma lucidum spore powder to obtain cobalt-modified porous carbon microspheres. 200 mg of cobalt-modified porous carbon microspheres were taken, and nitrogen, boron, and / or phosphorus sources were added, ground, and mixed evenly. The mixture was maintained at 400–1000 °C for 1.5–2.5 h under a nitrogen atmosphere. For the oxygen evolution reaction (OER) catalyst electrode material, the preparation method was as follows: cobalt particles were modified with heteroatom-doped carbon microspheres as an OER catalyst, dispersed in an ethanol solution; Nafion solution was added and ultrasonically dispersed, and the solution was coated onto a glassy carbon electrode and dried. The beneficial effect is that by chemically replacing carbon atoms in the original carbon material with heteroatoms, the electronic structure and electrochemical properties of the original carbon material are changed, further improving the electrochemical performance of the OER. In the optimization test, the OER reached 10 mA cm⁻¹. ‑2 At a current density of 1.58V, the minimum required potential is 1.58V.

Description

Technical Field

[0001] This invention belongs to the field of electrode material technology, specifically relating to a cobalt particle-modified heteroatom-doped carbon microsphere and its preparation method. Background Technology

[0002] With the increasing depletion of fossil fuels and the resulting severe environmental pollution, our demand for green and sustainable energy is growing. Hydrogen, with its environmentally friendly, abundant, and high energy density characteristics, is a green and renewable energy source that can replace fossil fuels. Water electrolysis is one of the most efficient methods for producing hydrogen. However, the kinetics of water electrolysis are very slow, and the high overpotential of the anodic oxygen evolution half-reaction severely limits the efficiency of the cathodic hydrogen evolution reaction. Therefore, researching efficient, stable, and low-cost catalysts to reduce the overpotential of the oxygen evolution reaction is key to improving the efficiency of water electrolysis.

[0003] Porous carbon materials possess abundant mesoporous structures, ultra-high specific surface areas, excellent electrochemical properties, and are inexpensive and readily available, making them widely used in electrode materials, gas separation, catalyst supports, and many other fields. However, their electrochemical activity is relatively low. Elemental doping can improve their electrochemical activity, and combining them with highly conductive materials is an effective strategy for developing novel non-noble metal oxygen evolution catalysts. The transition metal cobalt, with its excellent metallic properties and conductivity, exhibits good electrocatalytic activity. Introducing Co-CX and other oxygen evolution reaction catalytic active sites into porous carbon materials can enhance their oxygen evolution activity. Therefore, cobalt-modified heteroatom-doped carbon materials possess excellent catalytic activity and can be widely used in electrocatalytic reactions. Summary of the Invention

[0004] The purpose of this invention is to improve the catalytic activity of the electrocatalytic oxygen evolution reaction by providing a cobalt particle-modified heteroatom-doped carbon microsphere and its preparation method.

[0005] Cobalt particles modified heteroatom-doped carbon microspheres are prepared by the following method: 1) Co 2+ Ions were complexed on the surface of Ganoderma lucidum spore powder to obtain cobalt-modified porous carbon microspheres; 2) Take 200 mg of cobalt-modified porous carbon microspheres, add nitrogen source, phosphorus source and / or boron source, the total molar amount not exceeding 10 mmol; grind and mix evenly; 3) At a nitrogen flow rate of 150-300 ml / min -1 High-temperature carbonization is carried out at 400-1000℃ for 1.5-2.5 hours, with a heating / cooling rate of 1-30℃ / min during the reaction. -1 Cobalt particles were used to modify heteroatom-doped carbon microspheres. The cobalt-modified porous carbon microspheres are prepared by the following method: 1) Dissolve 1.0-3.0 g of Ganoderma lucidum spore powder and 0.5-2.5 g of Co(NO3)2·6H2O in water, stir until evenly dispersed, and heat at 50-90℃ for 4-10 h; 2) Filter, remove supernatant, and dry at 60-100℃ for 8-16 hours; 3) Place in the constant temperature zone of a tube furnace and purge with N2 for 5 min; maintain a nitrogen flow rate of 150-300 ml / min. -1 High-temperature carbonization is carried out at 400-1000℃ for 1.5-2.5 h, with a heating / cooling rate of 1-30℃ / min during the reaction. -1 ; 4) Cooling yields cobalt-modified porous carbon microspheres, labeled Co@C; In step 2), the nitrogen source is urea, melamine, or dicyandiamide; the phosphorus source is phytic acid, triphenylphosphine, or phosphoric acid; and the boron source is boric acid, triphenylborane, or triethylborane. The molar amount of nitrogen, phosphorus, and / or boron source added is 1-10 mmol. In step 2), a nitrogen source is added at a molar amount of 4 mmol; or a boron source is added at a molar amount of 2 mmol; or a phosphorus source is added at a molar amount of 8 mmol. In step 2), any two of the nitrogen source, boron source, and phosphorus source are added, with a total molar amount of 10 mmol and a molar ratio of 19:1 to 1:19 between any two of the substances. In step 2), a boron source and a phosphorus source are added in a molar ratio of 18:2; or a nitrogen source and a phosphorus source are added in a molar ratio of 13:7; or a nitrogen source and a phosphorus source are added in a molar ratio of 12:8. In step 2), the total molar amount added is 10 mmol, the molar amount of boron source added is 2 mmol, and the molar ratio of nitrogen source to phosphorus source is 19:1 to 1:19. In step 2), the amount of boron source added is 2 mmol, the total amount of nitrogen and phosphorus sources is 8 mmol, and the molar ratio of nitrogen and phosphorus sources added is 18:2.

[0006] The oxygen evolution catalyst electrode material is prepared by the following method: cobalt particles modified with heteroatom-doped carbon microspheres are used as oxygen evolution reaction catalysts and dispersed in an ethanol solution; Nafion solution is added, ultrasonically dispersed, the solution is coated on a glassy carbon electrode and dried to obtain the oxygen evolution catalyst electrode material. The ethanol solution is a mixture of ethanol and water in a volume ratio of 1:1, in which the ethanol and water are miscible.

[0007] This invention provides cobalt particle-modified heteroatom-doped carbon microspheres, which are prepared by the following method: 1) Co 2+1) Ions are complexed on the surface of Ganoderma lucidum spore powder to obtain cobalt-modified porous carbon microspheres; 2) Take 200 mg of cobalt-modified porous carbon microspheres, add nitrogen source, phosphorus source and / or boron source, the total molar amount does not exceed 10 mmol; grind and mix evenly; 3) Under nitrogen atmosphere, maintain at 400-1000℃ for 1.5~2.5h to obtain cobalt particle-modified heteroatom-doped carbon microspheres; Oxygen evolution catalyst electrode material, which is prepared by the following method: the cobalt particle-modified heteroatom-doped carbon microspheres are used as oxygen evolution reaction catalysts and dispersed in ethanol solution; Nafion solution is added, ultrasonically dispersed, the solution is coated on glassy carbon electrode and dried to obtain oxygen evolution catalyst electrode material; The beneficial effect is: using Ganoderma lucidum spore powder with chitin and dextran as the spore wall, taking advantage of its ability to adsorb metal ions, it can complex with metal ions to form complexes, and with Co 2+ Ions are complexed, followed by a high-temperature annealing process, Co 2+ Ions are reduced to metallic Co and distributed on the surface of carbon microspheres. Ganoderma lucidum spore powder has a layered network structure with pores of similar size on its surface, providing sufficient active sites for Co nucleation and increasing their nucleation rate. Further enhancing electrochemical activity can be achieved by chemically substituting carbon atoms in the original carbon material with heteroatoms (N, P, and B), thereby altering the electronic structure and electrochemical properties of the original carbon material. Furthermore, doping two or more heteroatoms with different electronegativity (e.g., N and P, P and B, N and B) into the carbon framework produces unique electron donor properties, which may lead to synergistic effects between the two or more heteroatoms, generating more structural defects during doping, thus further improving the electrochemical performance of the oxygen evolution reaction. Attached Figure Description

[0008] Figure 1 XRD pattern of Co-modified porous carbon microspheres prepared in this invention; Figure 2 Scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the Co-modified porous carbon microspheres prepared in this invention; Figure 3 LSV diagrams of the oxygen evolution reaction catalysts prepared in Examples 2, 3, and 4 of this invention; Figure 4 LSV diagrams of the oxygen evolution reaction catalysts prepared in Examples 5, 6, 7, and 8 of this invention. Detailed Implementation

[0009] Example 1: Preparation of Cobalt-Modified Porous Carbon Microspheres Using Ganoderma lucidum spore powder as the biomass carbon source and cobalt nitrate hexahydrate as the cobalt source, a hydrothermal process was employed to convert Co... 2+ Ions are complexed on the surface of Ganoderma lucidum spore powder; the specific preparation steps are as follows: 1) Dissolve 1.0g of Ganoderma lucidum spore powder and 1.445g of Co(NO3)2·6H2O in 50 ml of deionized water; 2) After stirring the solution until it is evenly dispersed, heat it at 80℃ for 6 h; filter, remove the supernatant, and dry it in a drying oven at 60℃ for 12 h; 3) Place the dried sample in the constant temperature zone of the tube furnace and purge with N2 for 5 min to purge air from the tube and prevent it from affecting the sample during the heating process; then purge with N2 at a flow rate of 200 ml / min. -1 Under these conditions, at 5℃ min -1 The heating rate was increased to 900℃ and maintained for 2 hours; 4) Cooling yields Co-modified porous carbon microspheres, labeled Co@C.

[0010] Figure 1 The XRD pattern of the prepared Co-modified porous carbon microspheres is shown. It can be seen that, apart from the broad peak at 24° corresponding to the characteristic peak of crystalline carbon, the diffraction peaks at 44.2°, 51.5°, and 75.8° correspond to the (111), (200), and (220) crystal planes of Co, respectively. This indicates that cobalt particles were successfully loaded onto the surface of the porous carbon microspheres.

[0011] Figure 2 SEM and TEM images of the prepared Co-modified porous carbon microspheres are shown. It can be seen that the carbon microspheres exhibit a core-shell shape and an internal network structure, which greatly increases the specific surface area and provides more active sites. Furthermore, most cobalt particles are clustered near the pores, and smaller cobalt particles may also exist within the pores, which can improve conductivity to some extent and contribute to enhanced catalytic activity.

[0012] Example 2: Preparation of cobalt-modified nitrogen-doped porous carbon microspheres Co-modified nitrogen-doped porous carbon microspheres: 200 mg Co@C and 4 mmol urea were placed in a mortar and ground until homogeneous. The mixture was then placed in a tube furnace and heated at a nitrogen flow rate of 150-300 ml / min. -1 High-temperature carbonization was carried out at 900℃ for 2 hours, with a heating / cooling rate of 1-30℃ / min during the reaction. Co-modified nitrogen-doped porous carbon microspheres were obtained and labeled as Co@NC.

[0013] Example 3: Preparation of cobalt-modified phosphorus-doped porous carbon microspheres Co-modified phosphorus-doped porous carbon microspheres: 200 mg Co@C and 8 mmol phytic acid were placed in a mortar and ground until homogeneous. The mixture was then placed in a tube furnace and heated at a nitrogen flow rate of 150-300 ml / min. -1High-temperature carbonization was carried out at 900℃ for 2 hours, with a heating and cooling rate of 1-30℃ / min during the reaction. -1 Co-modified phosphorus-doped porous carbon microspheres were prepared and labeled as Co@PC.

[0014] Example 4: Preparation of cobalt-modified boron-doped porous carbon microspheres Co-modified boron-doped porous carbon microspheres: 200 mg Co@C and 2 mmol boric acid were placed in a mortar and ground until homogeneous. The mixture was then placed in a tube furnace and heated with nitrogen at a flow rate of 150-300 ml / min. -1 High-temperature carbonization was carried out at 900℃ for 2 hours, with a heating and cooling rate of 1-30℃ / min during the reaction. -1 Co-modified boron-doped porous carbon microspheres were prepared and labeled Co@BC.

[0015] Example 5: Preparation of Cobalt-Modified Nitrogen-Phosphorus Dual-Doped Porous Carbon Microspheres Co-modified nitrogen-phosphorus dual-doped porous carbon microspheres: 200 mg Co@C, an appropriate amount of melamine, and phytic acid were placed in a mortar and ground until uniformly mixed. The mixture was then placed in a tube furnace and heated at a nitrogen flow rate of 150-300 ml / min. -1 High-temperature carbonization was carried out at 900℃ for 2 hours, with a heating and cooling rate of 1-30℃ / min during the reaction. -1 The total molar amount of nitrogen and phosphorus sources was 10 mmol, and the molar ratio of nitrogen to phosphorus sources was 12:8. Co-modified nitrogen-phosphorus-doped porous carbon microspheres were prepared and labeled as Co@NPC.

[0016] Example 6: Preparation of Cobalt-Modified Boron-Phosphorus Dual-Doped Porous Carbon Microspheres Co-modified boron-phosphorus co-doped porous carbon microspheres: 200 mg Co@C, appropriate amounts of boric acid and phosphoric acid were placed in a mortar and ground until homogeneous. The mixture was then placed in a tube furnace and heated at a nitrogen flow rate of 150-300 ml / min. -1 High-temperature carbonization was carried out at 900℃ for 2 hours, with a heating and cooling rate of 1-30℃ / min during the reaction. -1 The total molar amount of boron and phosphorus sources was 10 mmol, and the molar ratio of boron to phosphorus sources was 18:2. Co-modified nitrogen-phosphorus-doped porous carbon microspheres were prepared and labeled as Co@BPC.

[0017] Example 7: Preparation of Cobalt-Modified Nitrogen-Boron Dual-Doped Porous Carbon Microspheres Co-modified nitrogen-boron dual-doped porous carbon microspheres: 200 mg Co@C, an appropriate amount of urea, and triphenylboron were placed in a mortar and ground until uniformly mixed. The mixture was then placed in a tube furnace and heated at a nitrogen flow rate of 150-300 ml / min. -1High-temperature carbonization was carried out at 900℃ for 2 hours, with a heating and cooling rate of 1-30℃ / min during the reaction. -1 The total molar amount of nitrogen and boron sources was 10 mmol, and the molar ratio of nitrogen to boron sources was 13:7. Co-modified nitrogen-phosphorus-doped porous carbon microspheres were prepared and labeled Co@NBC.

[0018] Example 8: Preparation of Cobalt-Modified Nitrogen-Phosphorus-Boron Triple-Doped Porous Carbon Microspheres Co-modified nitrogen-phosphorus-boron triple-doped porous carbon microspheres: 200 mg Co@C, 2 mmol boric acid, appropriate amounts of dicyandiamide and phytic acid were placed in a mortar and ground until uniformly mixed. The mixture was then placed in a tube furnace and heated at a nitrogen flow rate of 150-300 ml / min. -1 High-temperature carbonization was carried out at 900℃ for 2 hours, with a heating and cooling rate of 1-30℃ / min during the reaction. -1 The total molar amount of nitrogen and phosphorus sources was 8 mmol, and the molar ratio of nitrogen to phosphorus sources was 18:2. Co-modified nitrogen-phosphorus-boron triple-doped porous carbon microspheres were prepared and labeled as Co@NPBC.

[0019] Example 9: Preparation and Performance Testing of Oxygen Evolution Catalyst Electrode Materials Preparation of oxygen evolution catalyst electrode material: Co-modified heteroatom-doped carbon microspheres were used as oxygen evolution reaction catalysts and dispersed in a solution in which ethanol and water were miscible in a volume ratio of 1:1. Nafion solution was added, and the mixture was ultrasonically dispersed. The solution was then coated onto a glassy carbon electrode and dried to obtain the oxygen evolution catalyst electrode material.

[0020] Electrochemical performance testing: Using Ag / AgCl as the reference electrode, Pt electrode as the counter electrode, and 1 mol / L KOH solution as the electrolyte, the electrochemical performance of the oxygen evolution catalyst electrode material was tested in a Chenhua CHI 760 electrochemical workstation.

[0021] The electrocatalytic oxygen evolution reaction potential of the sample obtained according to the method of the embodiment was measured, and the results are as follows: Figure 3 and Figure 4 As shown. It operates at a current density of 10 mA / cm². -2 The required potentials are shown in the table below. The minimum potential can reach 1.58V.

[0022] .

Claims

1. Cobalt particles modified heteroatom-doped carbon microspheres are prepared by the following method: 1) Co 2+ Ions were complexed on the surface of Ganoderma lucidum spore powder to obtain cobalt-modified porous carbon microspheres; 2) Take 200 mg of cobalt-modified porous carbon microspheres, add nitrogen source, phosphorus source and boron source, the total molar amount not exceeding 10 mmol; grind and mix evenly; 3) At a nitrogen flow rate of 150-300 ml / min -1 High-temperature carbonization is carried out at 400-1000℃ for 1.5-2.5 h, with a heating and cooling rate of 1-30℃ / min during the reaction. -1 Cobalt particles were used to modify heteroatom-doped carbon microspheres. In step 2), the amount of boron source added is 2 mmol, the total amount of nitrogen and phosphorus sources is 8 mmol, and the molar ratio of nitrogen and phosphorus sources added is 18:

2. The cobalt-modified porous carbon microspheres are prepared by the following method: 1) Dissolve 1.0-3.0 g of Ganoderma lucidum spore powder and 0.5-2.5 g of Co(NO3)2·6H2O in 50-150 ml of deionized water, stir until evenly dispersed, and heat at 50-90℃ for 4-10 h; 2) Filter, remove supernatant, and dry at 60-100℃ for 8-16 hours; 3) Place in the constant temperature zone of a tube furnace and purge with N2 for 5 min; maintain a nitrogen flow rate of 150-300 ml / min. -1 High-temperature carbonization is carried out at 400-1000℃ for 1.5-2.5 h, with a heating and cooling rate of 1-30℃ / min during the reaction. -1 ; 4) Cooling yields cobalt-modified porous carbon microspheres.

2. An oxygen evolution catalyst electrode material, which is prepared by the following method: using cobalt particles modified with heteroatom-doped carbon microspheres as described in claim 1 as an oxygen evolution reaction catalyst, dispersing them in an ethanol solution; adding Nafion solution, ultrasonically dispersing, coating the solution onto a glassy carbon electrode and drying, to obtain the oxygen evolution catalyst electrode material.

3. The oxygen evolution catalyst electrode material according to claim 2, characterized in that: The ethanol solution is a mixture of ethanol and water in a volume ratio of 1:1, in which they are miscible.

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