Doped Graphene Oxygen Reduction Catalyst

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Solution Overview

Problem

Increasing the heating temperature and time for preparing carbon-based crystals to enhance catalytic activity often results in decreased performance due to the formation of inactive metal compounds and metal crystals, which inhibit catalytic activity.

Innovation Solution

A carbon-based material is developed by doping graphene with metal and non-metal atoms such as nitrogen, boron, or phosphorus, where the diffraction pattern shows a low intensity ratio of inactive metal compound and metal crystal peaks to the (002) peak, indicating minimal inactive content, and is prepared by reducing graphene oxide with a metal and non-metal containing compound under controlled heating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heating temperature and heating time are increased to enhance catalytic activity, then the number of reaction active centers increases, but inactive metal compounds and metal crystals form which decrease catalytic performance

Engineering Contradiction:
Improvecatalytic activityVSAvoidinactive metal compound and metal crystal formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent optimizes heating temperature (700-900°C) and heating time (2-3 hours) parameters to achieve sufficient catalytic activity while preventing the formation of inactive metal compounds and metal crystals. This parameter optimization resolves the contradiction by finding the optimal processing conditions that maximize active centers without generating harmful byproducts

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs continuous heating under inert atmosphere throughout the carbonization process, maintaining stable reaction conditions that promote continuous formation of active carbon-based catalysts while preventing oxidation and decomposition that would lead to inactive metal compound formation

Inventive Principle:
Principle #20Continuity of useful action

2Quantity of substance

If heating time is increased to dope more iron and nitrogen in graphene sheets, then number of reaction active centers increases, but catalytic performance decreases

Engineering Contradiction:
Improveamount of iron and nitrogen dopingVSAvoidcatalytic performance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent optimizes heating time (2-3 hours) and temperature (700-900°C) to achieve sufficient doping of iron and nitrogen in graphene sheets while preventing the formation of inactive metal compounds. This parameter optimization ensures adequate active center formation without exceeding the threshold that would generate harmful byproducts

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach results in a carbon-based material with high catalytic activity for oxygen reduction reactions, maintaining high electrical conductivity and minimizing inactive metal compound and metal crystal content, thereby improving catalytic performance.

Implementation Method 1

chemically-reducing the graphene oxide of the mixture to graphene using a reducing agent

Methodology Applied
Scientific EffectChemical reduction: Reduction

Implementation Method 2

heating the resultant mixture at a heating temperature of 800°C for a heating time of two hours under argon atmosphere

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 3

a diffraction pattern obtained by X-ray diffraction measurement of the carbon-based material by use of CuKα radiation

Methodology Applied
Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentEP2792639B1Carbon-based material, electrode catalyst, oxygen reduction electrode catalyst, gas diffusion electrode, aqueous solution electrolysis device, and method of preparing carbon-based material
Publication Date: 2019.03.20 PANASONIC HOLDINGS CORP
  • EP2792639B1 patent drawingFigure 1~2
  • EP2792639B1 patent drawingFigure 3~4
  • EP2792639B1 patent drawingFigure 5~6

AI summary

The present invention provides a carbon-based material with high catalytic activity. The carbon-based material in accordance with the present invention includes graphene doped with metal atoms and at least one type of non-metal atoms selected from a group consisting of nitrogen atoms, boron atoms, sulfur atoms, and phosphorus atoms. A diffraction pattern obtained by X-ray diffraction measurement of the carbon-based material by use of CuK± radiation shows that a proportion of the highest of intensities of peaks derived from an inactive metal compound and a metal crystal to an intensity of a (002) peak is 0.1 or less.