Pt-Coated NbO2 Catalyst for Fuel Cell Durability

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Solution Overview

Problem

Fuel cells face challenges with anode contamination leading to corrosion of carbon supports, resulting in accelerated platinum coalescence and degraded oxygen transport, necessitating the development of more durable catalyst systems.

Innovation Solution

A method involving the deposition of a conformal Pt or platinum alloy thin layer on NbO2 substrate particles using reductive H2-plasma atomic layer deposition (ALD) to form Pt-coated NbO2 particles, which are then incorporated into fuel cell catalyst layers, providing corrosion resistance and improved CO tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbon black is used to support Pt catalyst, then good electrical conductivity and cost-effectiveness are achieved, but the carbon support is susceptible to oxidation at high potential leading to Pt coalescence and degraded performance

Engineering Contradiction:

Improvecatalyst durabilityVSAvoidcarbon oxidation at high potential

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a composite support structure consisting of NbO2 particles coated with a thin layer of Pt. This composite material combines the high electrical conductivity of Pt with the oxidation resistance of NbO2, creating a support that is immune to high-potential oxidation while maintaining necessary conductivity for fuel cell operation.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent uses a thin layer of Pt (rather than bulk Pt) to coat the NbO2 support. This minimizes the amount of expensive Pt required while still providing sufficient conductivity and catalytic activity, making the overall catalyst more cost-effective despite using a non-traditional support.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If NbO2 is used as catalyst support, then oxidation resistance is improved, but NbO2 can be oxidized to Nb2O5 which is non-conductive

Engineering Contradiction:

Improveoxidation resistanceVSAvoidelectrical conductivity

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent controls the oxidation state of NbO2 by adjusting deposition parameters during ALD processing. By carefully controlling temperature, pressure, and exposure time, the NbO2 surface is reduced to NbO or Nb which has high surface energy and binds strongly to Pt, preventing further oxidation to non-conductive Nb2O5 while maintaining electrical conductivity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a localized Pt coating on the NbO2 surface that serves dual functions: providing electrical conductivity pathways and preventing oxidation of the NbO2 support. The Pt layer acts as a protective barrier at the interface with the oxidizing environment while maintaining overall catalyst conductivity.

Inventive Principle:

Principle #3Local quality

3Power

If conventional Pt/C catalyst is used, then good catalytic activity is achieved, but CO coverage is high resulting in lower CO tolerance

Engineering Contradiction:

Improvecatalytic activityVSAvoidCO coverage

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent creates a composite Pt-NbO2 catalyst where the NbO2 support modifies the electronic properties of Pt. This composite structure reduces CO adsorption strength on Pt sites while maintaining hydrogen oxidation activity, resulting in lower CO coverage and improved CO tolerance compared to conventional Pt/C catalysts.

Inventive Principle:

Principle #40Composite materials

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

The Pt-coated NbO2 catalysts exhibit enhanced resistance to high potentials, retain Pt surface area better than existing materials, and demonstrate lower CO coverage and oxidation peaks, making them more CO tolerant and durable.

Implementation Method 1

The deposition step uses a reductive H2-plasma atomic layer deposition (ALD) process

Methodology Applied

Scientific EffectAtomic layer deposition (ALD): Chemical Vapour Deposition

Implementation Method 2

surface NbO2 is reduced to NbO or Nb which has high surface energy and binds strongly to Pt

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 3

Each electrode has finely divided catalyst particles (for example, platinum particles) supported on carbon particles to promote oxidation of hydrogen at the anode

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS10164265B2Corrosion-resistant catalyst

Publication Date: 2018.12.25 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A method for forming a corrosion-resistant catalyst for fuel cell catalyst layers is provided. The method includes a step of depositing a conformal Pt or platinum alloy thin layer on NbO2 substrate particles to form Pt-coated NbO2. The Pt-coated NbO2 particles are then incorporated into a fuel cell catalyst layer.