Heteroatom-doped graphene material with holes on the surface and its preparation, application and device

A heteroatom and graphene technology, applied in the field of electrochemistry, can solve the problems of easy aggregation of graphene sheets, high battery cost, and harsh operating conditions, so as to reduce van der Waals interaction, improve electrocatalytic performance, and reduce reaction temperature. Effect

Active Publication Date: 2017-10-20
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The cathodic oxygen reduction catalyst is mainly a Pt-based catalyst, but this catalyst mainly has the following problems: 1) The cost of the battery is high, and the catalyst used in the fuel cell is mainly a Pt-based catalyst, and the storage capacity of Pt is limited and expensive; 2 ) The catalyst has low anti-poisoning ability and stability; 3) The low-temperature performance of the battery is low, and the fuel cell is difficult to start at low temperature, and the efficiency is low
The disadvantages of using these two methods are: 1) the operating conditions are relatively harsh, the reaction temperature is high (usually >800 ° C), and the reaction time is long; 2) the degree of reduction is not high, and the C / O atomic ratio is only 10, which affects the The conductivity of heteroatom-doped graphene; 3) the degree of doping is not high, the amount of heteroatom doping is less than 10%, and it is not easy to control; 4) the preparation cost is high; 5) the prepared graphene sheets are easy to aggregate, due to High specific surface area, graphene is easy to aggregate due to strong van der Waals forces between planes
Oxygen reduction mainly occurs at the edge of the graphene sheet, and the practical utilization of the catalyst is low, which greatly hinders its application in batteries.

Method used

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  • Heteroatom-doped graphene material with holes on the surface and its preparation, application and device
  • Heteroatom-doped graphene material with holes on the surface and its preparation, application and device
  • Heteroatom-doped graphene material with holes on the surface and its preparation, application and device

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Embodiment 1

[0042] A preparation method of heteroatom-doped surface hole graphene material, specifically comprising the following steps:

[0043] (1) Synthesis of graphene oxide

[0044] Adopt improved Hummers method to prepare graphene oxide, its technological process is as follows:

[0045] (1-1) Assemble the reaction flask in an ice-water bath, add a solid mixture of 1g of expanded graphite powder and 2.5g of sodium nitrate to the reaction flask under stirring (the stirring speed is 500r / min), and then add 150mL of mass percentage 95% concentrated sulfuric acid, reacted in an ice-water bath for 30 minutes; then, added 15 g of potassium permanganate 60 times (1 min each time), controlled the reaction temperature at 0 ° C, and continued to react for 12 h; then added 150 mL of deionized water to dilute After stirring and reacting for 30 minutes (the rotating speed of stirring is 500r / min), the temperature was raised to 98° C. at a heating rate of 10° C. / min, and the heat preservation rea...

Embodiment 2

[0054] A nitrogen-doped surface with hole graphene material, the specific preparation method is: (comparative example related to the present invention, high temperature direct pyrolysis reduction method preparation)

[0055] (1) synthesis of graphene oxide: same as embodiment 1;

[0056] (2) synthesis of graphene oxide with holes on the surface: same as Example 1;

[0057] (3) 20 mg of graphene oxide with holes on the surface is placed in the center of the plasma high-temperature tubular reactor, and then a protective gas N is introduced at one end. 2 and gaseous heteroatom doping source NH 3 (N 2 with NH 3 The volume ratio of the plasma high temperature tubular reactor is 0.5:1), and the plasma high temperature tubular reactor is heated to 850°C at a heating rate of 5°C / min. 3 , after cooling to room temperature, the nitrogen-doped graphene material with holes on the surface prepared by the high-temperature direct pyrolysis reduction method is obtained.

[0058] The nitr...

Embodiment 3

[0060] A heteroatom doped surface graphene material with holes, the specific preparation method is:

[0061] (1) synthesis of graphene oxide: same as embodiment 1;

[0062] (2) synthesis of graphene oxide with holes on the surface: same as embodiment 1;

[0063] (3) Place 20 mg of graphene oxide with holes on the surface prepared above in the center of the plasma high-temperature tubular reactor, use a mechanical pump to vacuumize to remove impurities and water vapor, and reduce the pressure to 0.1Pa, and then use a molecular pump to pump Vacuum to 1×10 -4 Pa, then pass protective gas N at one end 2 and gaseous heteroatom doping source diborane to a pressure of 10Pa (the volume ratio of nitrogen to diborane is 0.5:1), heat the plasma high-temperature tubular reactor to 500°C at a heating rate of 10°C / min, and then open RF power supply, under the condition of RF power of 600W, perform plasma discharge for 60min, then turn off the RF and heating power supply, stop feeding dib...

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Abstract

The invention belongs to the field of electrochemistry, and discloses a heteroatom-doped graphene material with a hole in the surface and preparation and application thereof, as well as a device. The method comprises the following steps: adding concentrated HNO3 into a graphene oxide aqueous solution, sealing, performing ultrasonic reaction, stewing, pouring into deionized water, and performing centrifugation, filtering and drying to obtain graphene oxide with the hole in the surface; then putting the graphene oxide with the hole in the surface into a plasma high-temperature tubular reactor, vacucumizing, feeding protective gas and a heteroatom-doped source compound, heating, turning on a radio frequency power supply, performing plasma discharging for 10-60 minutes, turning off radio frequency and a heating power supply to stop feeding the heteroatom-doped source compound, and cooling to obtain the heteroatom-doped graphene material with the hole in the surface. The prepared material is higher in oxygen reduction catalysis activity and better in poisoning resistance effect and can be applied to the field of anode materials of a proton exchange membrane fuel battery, a direct alcohol type fuel battery and a metal-air battery.

Description

technical field [0001] The invention belongs to the field of electrochemistry, and relates to a graphene material, in particular to a heteroatom-doped graphene material with holes on the surface, its preparation method, application and special device. Background technique [0002] With the sustained and rapid economic development and the substantial increase in energy consumption in society, energy shortages and environmental pollution caused by the use of fossil energy have become bottlenecks restricting the healthy development of my country's economy. The development of new alternative energy sources is one of the effective ways to solve the increasingly serious energy problems. As energy conversion and storage devices, fuel cells and metal / air batteries have the advantages of high energy density and low cost. They have very broad application prospects in the fields of electric vehicles, portable mobile power supplies, and household power generation. One of the new energy...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J27/24B01J27/22B01J19/08H01M4/90
CPCY02E60/50
Inventor 蒋仲杰
Owner SOUTH CHINA UNIV OF TECH
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