Iridium Oxide Spinel Electrolysis Electrode for Low Overpotential
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Solution Overview
Problem
Existing alkaline water electrolysis anodes suffer from high oxygen overpotential and instability due to catalyst component loss, particularly when using renewable energy sources with sudden power fluctuations.
Innovation Solution
A method for producing an electrolysis electrode by coating a catalyst precursor composition containing a nickel component, a cobalt component, and an iridium component on the surface of an electrically conductive substrate, including a catalyst precursor composition comprising a catalyst precursor composition, which includes a nickel component, a cobalt component, and an iridium component on the surface of an electrically conductive substrate, followed by thermal treatment to form a catalyst layer with a nickel cobalt spinel oxide and iridium oxide, with specific mass ratios and thermal conditions to enhance stability and reduce oxygen overpotential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalyst layers are formed on nickel substrates for alkaline water electrolysis, then the electrode can operate in high-concentration aqueous alkali solution, but the oxygen overpotential remains high and catalyst component loss occurs during operation
Solution Approach 1:
The patent applies composite materials by forming a catalyst layer containing multiple metal components (Ni, Co, Ir) with specific oxide phases (NiCo2O4 spinel and IrO2) on the nickel substrate. This composite structure combines the advantages of different materials: NiCo2O4 provides structural stability and catalytic activity, while IrO2 enhances oxygen evolution reaction performance and prevents catalyst dissolution, thereby reducing both oxygen overpotential and catalyst component loss
Solution Approach 2:
The patent applies parameter changes by optimizing the atomic ratios of metal components (Ni:Co:Ir = 2:2:1 or 3:2:1) and controlling thermal treatment parameters (temperature, atmosphere, duration) to form specific oxide phases. By adjusting these parameters, the catalyst layer achieves optimal catalytic activity and stability, resolving the contradiction between low oxygen overpotential and high catalyst stability
2Adaptability or versatility
If renewable energy sources are used as power sources for water electrolysis, then environmental sustainability is improved, but sudden start/shutdown and load fluctuation cause severe deterioration of nickel-based anode performance
Solution Approach 1:
The patent applies beforehand cushioning by forming a stable IrO2 component in the catalyst layer that acts as a protective element against sudden power fluctuations. The IrO2 provides structural support and prevents catastrophic failure during rapid load changes, cushioning the impact of renewable energy variability on the nickel-based anode performance
3Quantity of substance
If nickel-based materials are used as alkaline water electrolysis anodes, then cost is reduced compared to noble metal anodes, but catalyst component loss occurs under severe operating conditions
Solution Approach 1:
The patent applies composite materials by combining affordable NiCo2O4 spinel oxide with a smaller amount of IrO2. This composite structure maintains low cost compared to pure noble metal anodes while the IrO2 component significantly reduces catalyst dissolution and component loss during operation in high-concentration alkali solution
Solution Approach 2:
The patent applies intermediary by using IrO2 as a mediator that protects the NiCo2O4 spinel oxide from dissolution in high-concentration aqueous alkali solution. The IrO2 forms a stable interface with the electrolyte, preventing direct attack on the nickel-based components and thereby reducing catalyst component loss while maintaining cost-effectiveness
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 electrolysis electrode exhibits low oxygen overpotential and improved catalyst stability, reducing iridium loss and maintaining high catalytic activity over time, especially under varying power conditions.
Implementation Method 1
a step of obtaining a primary baked product by thermal treating the electrically conductive substrate coated with the catalyst precursor composition at 320 to 600° C.; and a step of forming a catalyst layer containing a nickel cobalt spinel oxide and an iridium oxide directly or indirectly on the surface of the electrically conductive substrate by thermal treating the primary baked product at 350 to 600° C.
Data Source
AI summary
There provided a method for producing an electrolysis electrode having excellent catalytic activity such as low oxygen overpotential and including a catalyst having excellent stability such as reducing loss of a catalyst component such as iridium (Ir). The method for producing an electrolysis electrode includes a step of coating a catalyst precursor composition containing an iridium component and the like on a surface of an electrically conductive substrate, a step of obtaining a primary baked product by thermal treating the electrically conductive substrate coated with the catalyst precursor composition, and a step of forming a catalyst layer containing an iridium oxide on the surface of the electrically conductive substrate by thermal treating the primary baked product, wherein the iridium component is an iridium compound containing a carboxy group, and the content of nickel (Ni) is 10 to 35% by mass, the content of cobalt (Co) is 25 to 55% by mass, and the content of iridium (Ir) is 15 to 55% by mass in the catalyst precursor composition, provided that Ni+Co+Ir=100% by mass.