Nickel-Iron Electrode Surface Treatment for Higher OER Activity
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Solution Overview
Problem
Existing methods for producing electrodes for water electrolysis, such as those using nickel alloys, result in low oxygen evolution reaction (OER) activity, necessitating further improvements.
Innovation Solution
A method involving thermal treatment of a nickel alloy substrate to form a surface layer rich in iron, followed by etching with specific acids to create a porous structure, without the need for catalyst coating, and optionally incorporating an intermediate and catalyst layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etching treatment methods are used on nickel alloy substrates, then the substrate surface is cleaned and catalyst layer adhesion is improved, but the oxygen evolution reaction activity remains insufficient
Solution Approach 1:
The patent applies preliminary action by performing thermal treatment before etching to pre-form an iron-rich surface layer on the nickel alloy substrate. This pre-preparation step creates a surface composition that will yield superior OER activity after subsequent etching, rather than directly etching the as-received substrate. The thermal treatment at 500-600°C for 1-5 hours redistributes iron to the surface, creating the necessary compositional foundation for high activity.
Solution Approach 2:
The patent employs parameter changes by modifying the thermal treatment parameters (temperature range of 500-600°C, time of 1-5 hours) to optimize iron surface enrichment. Additionally, the etching parameters are optimized (boiling temperature, 30-120 minutes duration, specific acid concentrations) to achieve the desired porous structure with maximum OER activity. These controlled parameter variations transform the substrate surface properties to overcome the activity limitation of conventional methods.
2Reliability
If catalyst coating is applied to improve OER activity, then reaction performance increases, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies self-service by enabling the nickel alloy substrate itself to provide the catalytic function through thermal treatment-induced iron enrichment and subsequent etching-created porous structure. The substrate's own iron content, when properly distributed and structured, becomes the active catalytic component, eliminating the need for external catalyst materials like iridium or ruthenium coatings. This self-catalytic approach reduces both manufacturing complexity and material costs while achieving comparable or superior OER activity.
Solution Approach 2:
The patent discards the conventional approach of adding external catalyst coatings and instead recovers/utilizes the iron already present in the nickel alloy substrate. By thermally treating the substrate, the iron is redistributed to the surface and concentrated in the porous structure formed after etching. This recovers the catalytic potential inherent in the substrate material itself, eliminating waste of expensive catalyst materials and simplifying the overall electrode structure.
3Ease of manufacture
If etching treatment is performed to remove organic materials and improve adhesion, then surface preparation is achieved, but oxygen evolution reaction activity is not sufficiently enhanced
Solution Approach 1:
The patent applies preliminary action by performing thermal treatment before etching to pre-form an iron-rich surface layer on the nickel alloy substrate. This pre-preparation step creates a surface composition that will yield superior OER activity after subsequent etching, rather than directly etching the as-received substrate. The thermal treatment at 500-600°C for 1-5 hours redistributes iron to the surface, creating the necessary compositional foundation for high activity.
Solution Approach 2:
The patent employs parameter changes by modifying the thermal treatment parameters (temperature range of 500-600°C, time of 1-5 hours) to optimize iron surface enrichment. Additionally, the etching parameters are optimized (boiling temperature, 30-120 minutes duration, specific acid concentrations) to achieve the desired porous structure with maximum OER activity. These controlled parameter variations transform the substrate surface properties to overcome the activity limitation of conventional methods.
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 method enhances OER activity, producing an electrode suitable for oxygen evolution anodes with improved performance.
Implementation Method 1
a thermal treatment step of subjecting the electrically conductive substrate composed of the nickel alloy to a thermal treatment
Implementation Method 2
the thermal treatment step of subjecting the electrically conductive substrate composed of the nickel alloy to a thermal treatment, thereby forming a surface layer containing Fe as a main component
Implementation Method 3
an etching step of etching the thermally treated electrically conductive substrate with an etchant
Data Source
Figure 1A~2A
Figure 2B~3B
Figure 4A~5
AI summary
The present invention provides a simple method for producing an electrode having improved oxygen evolution reaction (OER) activity without a need for catalyst coating and an electrode produced by this production method. The method is a method for producing an electrode including a step of subjecting an electrically conductive substrate comprising a nickel alloy comprising 30 to 70% by mass of Ni and 30 to 70% by mass of Fe, provided that Ni + Fi = 100% by mass, to a thermal treatment, and a step of etching the thermally treated electrically conductive substrate with an etchant comprising at least any acid of an organic acid and a weak inorganic acid. The electrode is an electrode that is produced by this production method and that is useful as an oxygen evolution anode or the like.