Electrolysis Electrode Catalyst Composition for Low Overvoltage

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Solution Overview

Problem

Conventional electrodes for sodium chloride electrolysis, such as DSA anodes, experience high initial overvoltage and have durability issues, leading to power consumption losses and inadequate long-term performance due to high chlorine generating overvoltage.

Innovation Solution

An electrode with a catalyst layer comprising ruthenium, iridium, titanium, and a first transition metal element like vanadium, with specific content ratios and forming a solid solution, is developed to reduce initial overvoltage and enhance durability, allowing for low voltage and low power consumption during electrolysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional DSA anodes are used, then chlorine generation is achieved, but initial overvoltage becomes high and power consumption increases

Engineering Contradiction:
Improvepower consumptionVSAvoidinitial overvoltage
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the catalyst layer by incorporating specific transition metal elements (Mn, Fe, Co, Ni, Cu, or Zn) in controlled amounts (0.1-10 wt%) alongside Ru and Ir oxides. This compositional parameter change enables the electrode to achieve low initial overvoltage while maintaining stable chlorine generation, directly resolving the contradiction between power consumption and initial overvoltage

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite catalyst layer material combining Ru oxide, Ir oxide, and transition metal oxides in specific proportions. This composite structure synergistically combines the high chlorine generation activity of Ru with the stability of Ir and the overvoltage-reducing effect of transition metals, achieving both low power consumption and reliable performance from the initial stage

Inventive Principle:
Principle #40Composite materials

2Productivity

If electrolysis is continued over a long period, then production continues, but voltage increases due to impurities and other causes

Engineering Contradiction:
Improvecontinuous productionVSAvoidvoltage increase
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The catalyst layer composition with transition metal elements maintains stable catalytic activity over extended operation periods. The transition metals prevent deactivation and maintain consistent chlorine generation efficiency, enabling continuous production without the voltage increases that typically occur during long-term electrolysis, thus reducing energy loss while maintaining productivity

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If catalyst layer contains only Ru and Ir oxides, then chlorine generation occurs, but overvoltage does not sufficiently lower and durability is inadequate

Engineering Contradiction:
ImprovedurabilityVSAvoidovervoltage
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention modifies the catalyst layer composition by adding transition metal elements in specific quantities (0.1-10 wt%) to the Ru-Ir oxide system. This parameter change optimizes both the electronic structure and surface properties of the catalyst, simultaneously achieving lower overvoltage and enhanced durability through improved resistance to impurity accumulation and structural degradation

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

The electrode achieves reduced overvoltage at the initial stage of electrolysis, enabling long-term operation at low voltage and low power consumption, improving the durability and efficiency of the electrolysis process.

Implementation Method 1

a catalyst layer formed on a surface of the conductive substrate, wherein the catalyst layer comprises ruthenium element, iridium element, titanium element, and at least one first transition metal element

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

Sodium chloride electrolysis by ion exchange membrane process is a method for electrolyzing brine using electrode for electrolysis to thereby produce caustic soda, chlorine, and hydrogen

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Data Source

PatentEP3546619B1Electrode for electrolysis
Publication Date: 2021.01.06 ASAHI KASEI KOGYO KABUSHIKI KAISHA
  • EP3546619B1 patent drawingFigure 1
  • EP3546619B1 patent drawingFigure 2
  • EP3546619B1 patent drawing

AI summary

An electrode for electrolysis according to the present invention is an electrode for electrolysis including a conductive substrate; and a catalyst layer formed on a surface of the conductive substrate, wherein the catalyst layer comprises ruthenium element, iridium element, titanium element, and at least one first transition metal element selected from the group consisting of Sc, V, Cr, Fe, Co, Ni, Cu, and Zn, a content ratio of the first transition metal element contained in the catalyst layer based on 1 mol of the titanium element is 0.25 mol % or more and less than 3.4 mol %, and a D value being an indicator of an electric double layer capacitance of the electrode for electrolysis is 120 C/m2 or more and 420 C/m2 or less.