Hydrothermal Synthesis of Active M-N-C Catalysts

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Solution Overview

Problem

The high cost of platinum-based catalysts in fuel cell technology and the limitations of existing non-platinum group metal-free (PGM-free) catalysts, particularly the use of corrosive chemicals in sacrificial support methods, necessitate the development of cost-effective, performance-competitive catalysts without these drawbacks.

Innovation Solution

A novel thermo-chemical synthesis method using chemically defined precursors for Metal-Nitrogen-Carbon (M-N-C) catalysts, involving hydrothermal synthesis and pyrolysis, which results in high yields of graphitic carbon and the formation of catalytic centers, avoiding the use of corrosive chemicals and producing catalysts with improved conductivity and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If platinum-based catalysts are used in fuel cells, then catalytic performance is improved, but manufacturing cost increases significantly

Engineering Contradiction:

Improvecatalytic performanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive platinum-based catalysts with non-platinum group metal-free (PGM-free) catalysts composed of carbon, nitrogen, and transition metals. These alternative catalysts achieve sufficient catalytic performance for oxygen reduction reactions while dramatically reducing manufacturing costs, embodying the principle of substituting expensive materials with cheaper alternatives that meet performance requirements

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent develops composite M-N-C catalysts consisting of metal atoms coordinated with nitrogen in a carbon matrix. These composite materials combine the benefits of transition metals (catalytic activity) with nitrogen-doped carbon (structural stability and conductivity), achieving cost-effective catalytic performance that competes with platinum-based catalysts

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If sacrificial support method is used to produce PGM-free catalysts, then catalyst structure is improved, but use of corrosive chemicals increases

Engineering Contradiction:

Improvecatalyst structureVSAvoidcorrosive chemicals

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent removes the harmful element (corrosive chemicals like hydrofluoric acid or strong bases) from the synthesis process by replacing the sacrificial support method with direct hydrothermal synthesis. This extraction of harmful substances maintains the ability to produce structured catalysts while eliminating the associated hazards and environmental concerns

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the synthesis parameters from conventional high-temperature pyrolysis with sacrificial supports to hydrothermal conditions (aqueous environment, moderate temperature and pressure). This parameter change enables catalyst formation with controlled structure and composition without requiring corrosive chemicals, thus resolving the contradiction between manufacturing precision and harmful factors

Inventive Principle:

Principle #35Parameter changes

3Productivity

If conventional pyrolysis methods are used, then catalyst formation is achieved, but graphitic carbon yield decreases

Engineering Contradiction:

Improvecatalyst formation efficiencyVSAvoidgraphitic carbon yield

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent changes the thermal processing parameters from conventional high-temperature pyrolysis to controlled hydrothermal treatment followed by moderate pyrolysis. This parameter optimization promotes graphitization of carbon structures, significantly increasing graphitic carbon yield while maintaining catalyst formation efficiency and avoiding excessive energy consumption

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 method achieves high yields of graphitic carbon and the formation of gamma iron, leading to enhanced catalytic performance and stability, overcoming the limitations of amorphous carbon and corrosive chemical use in existing methods, while reducing costs and improving electron conductivity.

Implementation Method 1

the methods utilize thermo-chemical synthesis of chemically defined precursors to produce a de novo catalytic material

Methodology Applied

Scientific EffectHydrothermal synthesis:

Implementation Method 2

involving hydrothermal synthesis and pyrolysis, which results in high yields of graphitic carbon and the formation of catalytic centers

Methodology Applied

Scientific EffectPyrolysis: Pyrolysis

Implementation Method 3

the methods utilize thermo-chemical synthesis of chemically defined precursors to produce a de novo catalytic material

Methodology Applied

Scientific EffectThermo-chemical synthesis:

Data Source

PatentUS11103863B1Active catalysts synthesized by hydrothermal methods

Publication Date: 2021.08.31 UNM RAINFOREST INNOVATIONS

AI summary

Methods for synthesis of active M-N—C catalysts utilizing thermo-chemical synthesis of chemically defined precursors and materials made thereby.