Iridium Nanoparticle Electrodes for Water Splitting

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Solution Overview

Problem

The existing methods for electrochemical water splitting using iridium electrodes are limited by high energy input requirements and the difficulty and expense of producing high-quality nanoparticulate iridium on a production scale.

Innovation Solution

A novel method for synthesizing iridium nanoparticles by adding a surfactant to a reagent complex of zero-valent iridium and a hydride, using ball-milling and solvent systems, to create electrodes with iridium nanoparticles suitable for efficient electrolytic production of oxygen from water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If nanoparticulate iridium is used as electrode material, then electrochemical efficiency is improved, but manufacturing cost and difficulty increase

Engineering Contradiction:

Improveelectrochemical efficiencyVSAvoidmanufacturing difficulty

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

A surfactant is introduced as an intermediary substance during the ball-milling synthesis process. The surfactant facilitates the formation of uniform nanoparticulate iridium by mediating between the reagent complex and the milling media, enabling controlled nanoparticle formation without requiring complex specialized equipment or multi-step purification processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the synthesis parameters by using ball-milling with controlled milling time, speed, and atmosphere, combined with surfactant addition. This transforms the synthesis from a complex multi-step process into a simplified single-step mechanical synthesis that produces consistent nanoparticulate iridium with controlled size and distribution.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If high-quality nanoparticulate iridium is obtained, then electrode performance is improved, but production cost increases

Engineering Contradiction:

Improveelectrode performanceVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention uses inexpensive, readily available materials including commercial iridium powder, common surfactants, and standard ball-milling equipment. The synthesis produces sufficient nanoparticulate iridium for practical electrode applications without requiring expensive specialized reagents or prolonged processing that would increase costs.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention replaces complex chemical synthesis methods with mechanical ball-milling. This substitution eliminates the need for sophisticated chemical reactors, temperature control systems, and multi-step purification equipment, thereby reducing manufacturing complexity and cost while maintaining high nanoparticle quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If energy input is increased to improve water splitting efficiency, then oxygen production increases, but energy loss increases

Engineering Contradiction:

Improveoxygen productionVSAvoidenergy loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The nanoparticulate iridium electrodes produced by this method possess inherent catalytic activity that enables them to facilitate water splitting at lower applied potentials. The high surface area and reactive nature of the nanoparticles allow the electrode to serve its function more efficiently, reducing the external energy input required and minimizing energy losses.

Inventive Principle:

Principle #25Self-service

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 synthesized iridium nanoparticles enable electrodes to produce oxygen with superior electrochemical performance and consistency across multiple cycles, generating higher current density and oxygen quantity compared to electrodes using commercially obtained iridium.

Implementation Method 1

adding surfactant to a reagent complex according to Formula I

Methodology Applied

Scientific EffectSurfactant: Surfactant

Implementation Method 2

iridium metal and/or oxide have been used as an electrode active material for the electrolytic production of oxygen gas from water

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 3

electrochemical oxidation/reduction of water, or 'water splitting'—conversion of H2O to H2 and O2 by application of electrical potential across electrodes

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Data Source

PatentUS10125429B2Electrodes containing iridium nanoparticles for the electrolytic production of oxygen from water

Publication Date: 2018.11.13 TOYOTA JIDOSHA KK

AI summary

Electrodes employing as active material iridium nanoparticles synthesized by a novel route are provided. The nanoparticle synthesis is facile and reproducible, and provides iridium nanoparticles of very small dimension and high purity for a wide range of metals. The electrodes utilizing these nanoparticles have excellent efficiency catalyzing the electrolytic production of oxygen from water.