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Preparation method of three-dimensional graphene co-doped with iron and nitrogen

A co-doping and graphene technology, applied in graphene, chemical instruments and methods, structural parts, etc., can solve the problems of metals being easily removed by acid, low catalytic performance, and insufficient durability

Inactive Publication Date: 2019-07-23
SHANDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The present invention differs from metal-nitrogen-carbon clusters prepared by pyrolysis of simple nitrogen-containing organic compounds and transition metal complexes or nitrogen-containing polymers, such as urea resin, melamine resin, etc., and transition metal mixtures in that metal-nitrogen-carbon clusters The atomic cluster is not a graphene structure and has no large π effect, so the catalytic performance is not high, and its metal is easily removed by acid, so the durability is not good enough, especially because the metal-nitrogen-carbon cluster is not a porous structure and its mass transfer effect not good

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014][Example 1] Preparation of mPBI: Add polyphosphoric acid (PPA) (100 g) into a three-necked flask equipped with electric stirring and nitrogen protection, and stir at 160° C. for 1 h under nitrogen protection to remove excess water and air. DABz (4g, 18.7mmol) and isophthalic acid (3.1g, 18.7mmol) were mixed evenly, and slowly added into a three-necked flask. The nitrogen flow rate was controlled to prevent DABz from being oxidized, and at the same time, the reaction temperature was raised to 200° C., and the reaction was continued for 5-8 hours with insulation and stirring. With the increase of reaction time, the polymerization system gradually became viscous. Stop the reaction when the viscosity is appropriate, slowly transfer the reaction mixture to a large amount of deionized water, spin, wash, dry, pulverize, and wash with deionized water several times to remove polyphosphoric acid and unreacted reactants to obtain mPBI. The molecular weight of mPBI was determined w...

Embodiment 2

[0015] [Example 2] Synthesis of mPBI by solid-phase method: DABz (4g, 18.7 mmol) and isophthalic acid (3.1g, 18.7 mmol) were mixed in a mortar, thoroughly ground and mixed, and transferred to a stirrer with nitrogen protection. in the three-neck flask. Nitrogen was passed for 15 minutes to exhaust the air in the flask. N 2 Protected and stirred, heated in an oil bath at 225°C for 3h. Take it out after cooling, grind finely, N 2 Under protection, heat in an electric furnace, raise the temperature to 270-275°C, and keep it for 3 hours. After cooling to room temperature, the product was taken out and finely ground to obtain mPBI, and the molecular weight of mPBI was measured with an Ubbelohde viscometer.

[0016] The preparation method of ABPBI is similar to that of mPBI, except that 3,4-diaminobenzoic acid (DABA) is used instead of DABz and isophthalic acid. ABPBI can be obtained using only one raw material. Other reaction conditions and operation steps are with embodiment...

Embodiment 3

[0017] [Example 3] MgO with a particle diameter of 30 nm is used as a template, the mass ratio of ferric acetate and PBI for iron salt is 1:2, and mPBI is used for PBI, and the mass ratio of mPBI and MgO template is 1:1 as an example: In a 250mL beaker, add 1g of mPBI (viscosity-average molecular weight: 30,000 to 50,000) and 20mL DMAc, heat and stir to dissolve, add 0.5 g of iron acetate in 20mL DMAc solution under stirring, and keep warm at 80°C to 100°C , stirring and reacting for 5-8 hours, slowly adding 1 g of nanometer MgO particles with a particle size of 30 nm, and stirring for 4-6 hours to make them uniformly dispersed. The obtained viscous liquid was heated and concentrated to nearly dryness under stirring, and dried in a vacuum oven at 100°C. The solid was ground in a mortar, transferred to a porcelain boat, and kept in an electric furnace at 900°C under the protection of argon. Pyrolyze for 2-3 hours, wait for the furnace temperature to drop to room temperature, ta...

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Abstract

Invented a method for preparing iron and nitrogen co-doped three-dimensional graphene. Soluble fully aromatic polybenzimidazole (PBI) is used as the carbon source and nitrogen source. The iron salt reacts with the PBI solution to obtain a complex formed by PBI and iron ions. The nanoparticle template is added to the mixture, mixed evenly, and concentrated for use. The complexes are coated and arranged regularly on the surface of the template, and the template is pyrolyzed and removed to obtain iron and nitrogen co-doped three-dimensional graphene. The viscosity-average molecular weight of PBI is 20,000-40,000; the mass ratio of PBI to iron salt is 1:2-2:1; the template agent is nano-particles such as nano-magnesium oxide, iron oxide, and iron hydroxide; the particle size of the template agent is 5-50nm ; The mass ratio of PBI to template is 3:1~1:3; the pyrolysis temperature is 700℃~1100℃. The products can be used in redox reaction catalysts, fuel cells, metal-air battery oxygen reduction catalysts, electrolytic water oxygen evolution catalysts, supercapacitors and other fields.

Description

technical field [0001] It belongs to the field of nanomaterial preparation and is used in redox reaction catalysts in chemical production, fuel cells in the field of clean energy, metal-air battery cathode catalysts, electrolytic water catalysts, lithium-ion battery materials, supercapacitor electrode materials and electrochemical sensors. Background technique [0002] Graphene is made of carbon atoms taken sp 2 Hybridization consists of carbon atoms forming hexagons, a two-dimensional structural carbon material with a perfect structure, due to its special properties, it has a very broad application prospect. Since graphene has characteristics such as good electrical conductivity and large specific surface area, it has become one of the research hotspots in the field of electrochemistry as an oxygen reduction catalyst (Kumar M P, et al. J. Electrochem. Soc. (Journal of the American Electrochemical Society) ), 2016, 163: F848). Studies have shown that compared with carbon a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B32/184H01M4/88H01M4/90
CPCC01B2204/04C01B2204/22C01B2204/32C01P2002/70C01P2002/85C01P2004/03C01P2004/04C01P2004/30C01P2006/14C01P2006/16H01M4/8825H01M4/9008Y02E60/50
Inventor 李忠芳王素文岳攀峰
Owner SHANDONG UNIV OF TECH