Preparation of 3D graphene co-doped with cobalt and nitrogen

A co-doping and templating agent technology, which is applied in chemical instruments and methods, physical/chemical process catalysts, chemical/physical processes, etc., can solve the problem that metals are easily removed by acid, the mass transfer effect is not good, and the durability is not good enough And other issues

Inactive Publication Date: 2017-04-26
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 size of 30nm is used as a template, the mass ratio of cobalt acetate and PBI for cobalt 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 cobalt acetate in 20mL DMAc solution under stirring, and keep warm at 80°C to 100°C. Stir and react for 5-8 hours, slowly add 1 g of nanometer MgO particles with a particle size of 30 nm, and stir 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 120°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, take it out, and g...

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Abstract

The invention relates to a preparation of 3D graphene co-doped with cobalt and nitrogen. The 3D graphene co-doped with cobalt and nitrogen is prepared by regularly arranging complexes formed by soluble all-aromatic PBI (polybenzimidazole) and cobalt salt on template nanoparticle surfaces through pyrolysis, template removal and other process routes. PBI is selected from all-aromatic polymers such as ABPBI, mPBI and the like, and the viscosity average molecular weight ranges from 20,00 to 40,000; the mass ratio of PBI to cobalt salt is 1:2-2:1; the template is nanoparticles such as nano magnesium oxide, iron oxide, ferric hydroxide and the like and has the particle size of 5-50 nm; the mass ratio of PBI to the template is 3:1-1:3; the pyrolysis temperature is 700-1,100 DEG C. The product can be applied to the fields of redox reaction catalysts, fuel cells, metal-air battery redox catalysts, water electrolysis oxygen precipitation catalysts, supercapacitors and the like.

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 a two-dimensional carbon material with a hexagonal structure composed of carbon atoms. It has attracted people's attention because of its special physical and chemical properties and broad application prospects. As an oxygen reduction catalyst, it has become one of the research hotspots in the field of electrochemistry (Raccichini R, et al. Nature materials, 2015, 14: 271). Studies have shown that in nitrogen-doped graphene molecules, due to the high electronegativity of nitrogen atoms, the introduction of nitrogen atoms makes the carbon atoms adjacent to it positively charged, and the nitrogen ato...

Claims

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Application Information

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IPC IPC(8): B01J27/24
CPCB01J27/24
Inventor 李忠芳王素文岳攀峰
Owner SHANDONG UNIV OF TECH
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