Iridium-Platinum Alloy Cathode for Hydrogen Generation

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Solution Overview

Problem

Current cathodes for hydrogen generation in electrolysis suffer from high hydrogen overvoltage and durability issues, particularly when exposed to reverse current and Fe ions in the electrolytic solution, leading to oxidative deterioration and catalyst drop-off.

Innovation Solution

A cathode with a catalyst layer composed of crystalline iridium oxide and iridium-platinum alloy, where the iridium oxide framework supports platinum, forming an alloy that inhibits weight reduction and enhances resistance against reverse current, with a specific X-ray diffraction peak and mole ratio of platinum to iridium, is used.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cathode materials (soft steel, stainless steel, nickel) are used, then the cathode structure is simple and cost-effective, but hydrogen overvoltage is high and durability against reverse current is poor

Engineering Contradiction:

Improvedurability against reverse currentVSAvoidcathode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention uses a composite catalyst layer comprising iridium oxide and iridium-platinum alloy on a conductive base material. This composite structure combines the oxidation resistance of iridium oxide with the catalytic activity of platinum, achieving both durability against reverse current and low hydrogen overvoltage without requiring complex multi-layer structures or additional protective systems.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention optimizes the mole ratio of platinum to iridium in the range of 20-50 atom% Pt to achieve the best balance between catalytic activity and oxidation resistance. This parameter optimization allows the cathode to maintain low hydrogen overvoltage while resisting oxidative deterioration from reverse current, eliminating the need for complex protective mechanisms.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If platinum is used as catalyst, then hydrogen overvoltage is low, but the catalyst layer drops off during electrolysis and requires protection current

Engineering Contradiction:

Improvehydrogen overvoltageVSAvoidcatalyst layer stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The invention creates a composite catalyst layer where iridium oxide serves as a stable framework that prevents platinum drop-off during electrolysis. The iridium-platinum alloy maintains low hydrogen overvoltage while the iridium oxide component provides structural stability and oxidation resistance, eliminating the need for protection current systems.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Iridium oxide acts as an intermediary material that supports the platinum catalyst, preventing its physical drop-off during electrolysis while maintaining its catalytic function. This intermediary framework allows platinum to function effectively without requiring additional protective measures.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If protection current is passed to prevent oxidative deterioration, then cathode durability is improved, but operational procedures become complicated and ancillary facilities cost increases

Engineering Contradiction:

Improvecathode durabilityVSAvoidoperational procedure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The cathode is designed to be self-protecting against oxidative deterioration through its intrinsic composition. The iridium oxide framework and iridium-platinum alloy naturally resist oxidation from reverse current without requiring external protection current systems, simplifying operational procedures and eliminating ancillary protection facilities.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention converts the potentially harmful reverse current that causes oxidative deterioration into a beneficial testing condition that validates the cathode's inherent oxidation resistance. The iridium oxide framework withstands the oxidative environment, demonstrating the cathode's self-protection capability without requiring additional protective measures.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 cathode achieves low hydrogen overvoltage, high durability, and resistance against reverse current and Fe ions, reducing operational costs and improving long-term performance.

Implementation Method 1

the catalyst layer includes crystalline iridium oxide, platinum and iridium-platinum alloy... achieves low hydrogen overvoltage

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

iridium oxide framework supports platinum, forming an alloy that inhibits weight reduction and enhances resistance against reverse current

Methodology Applied

Scientific EffectAlloy formation:

Data Source

PatentEP2292811B1Cathode for hydrogen generation and method for producing the same

Publication Date: 2017.02.15 ASAHI KASEI KOGYO KABUSHIKI KAISHA

AI summary

The present invention provides an excellent durable cathode for hydrogen generation, which has a low hydrogen overvoltage and reduced dropping-off of a catalyst layer against the reverse current generated when an electrolyzer is stopped, and a method for producing the same. The present invention provides a cathode for hydrogen generation having a conductive base material and a catalyst layer formed on the conductive base material, wherein the catalyst layer includes crystalline iridium oxide, platinum and iridium - platinum alloy.