Ruthenium Lanthanum Electrode Coating for Hydrogen Generation
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Solution Overview
Problem
Ion-exchange membrane electrolysis for hydrogen generation in brine requires reducing energy consumption and maintaining low hydrogen overvoltage, while preventing contamination of the membrane and ensuring stable operation at high current densities.
Innovation Solution
A hydrogen electrode with a coating layer formed by heat-treating a material containing ruthenium nitrate and lanthanum carboxylate in an oxygen-containing atmosphere, avoiding chlorine compounds to maintain catalytic activity and prevent membrane contamination, with a Ru/La atom ratio between 30/70 and 90/10 for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a electrode catalyst coating of nickel, cobalt, platinum group metal or oxide is formed on a metal base member, then hydrogen generation catalytic activity is improved, but the ion-exchange membrane becomes contaminated with heavy metal elution
Solution Approach 1:
The patent introduces an intermediary layer (oxide coating layer) between the metal base member and the ion-exchange membrane. This intermediary layer serves as a barrier that prevents heavy metal elution from the electrode catalyst coating from contaminating the ion-exchange membrane, while still allowing hydrogen generation catalytic activity to function effectively.
Solution Approach 2:
The patent employs a composite structure consisting of a metal base member, an oxide coating layer, and an electrode catalyst coating. This composite material approach combines the catalytic activity of the electrode catalyst with the protective properties of the oxide layer, achieving both hydrogen generation efficiency and membrane protection from heavy metal contamination.
2Productivity
If high current density is used for electrolysis, then hydrogen generation productivity is improved, but hydrogen overvoltage increases and energy consumption rises
Solution Approach 1:
The patent optimizes the composition and structure parameters of the electrode catalyst coating, specifically controlling the particle size, surface area, and metal distribution to maintain low hydrogen overvoltage even at high current densities. The oxide coating layer thickness and composition are also optimized to prevent polarization effects.
3Productivity
If chlorine-containing metal compounds are used in electrode catalyst coating formation, then catalytic activity is improved, but the ion-exchange membrane is damaged upon contact
Solution Approach 1:
The patent extracts and removes chlorine from the metal compound formulation used in electrode catalyst coating formation. By eliminating chlorine-containing compounds and using alternative metal salts without chlorine, the patent maintains catalytic activity while preventing chlorine-induced damage to the ion-exchange membrane.
Solution Approach 2:
The patent converts the potential harm of using effective metal catalysts into a benefit by carefully selecting metal compounds that provide catalytic activity without harmful chlorine content. The oxide coating layer is also utilized to further protect the membrane from any potential harmful interactions.
4Ease of manufacture
If electrode catalyst coating is exposed to atmosphere, then manufacturing is simplified, but the coating layer degrades due to oxygen exposure
Solution Approach 1:
The patent converts the harmful effect of oxygen exposure into a benefit by using an oxide coating layer as a protective barrier. This oxide layer, formed by heat treatment in an oxygen-containing atmosphere, actually protects the underlying metal catalyst from oxidation and degradation, improving the overall stability of the electrode catalyst coating.
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 maintains low hydrogen overvoltage and prevents membrane contamination, ensuring stable operation at both low and high current densities, with enhanced catalytic activity and durability against atmospheric exposure.
Implementation Method 1
the electrode catalyst coating layer... is highly catalysis-active relative to hydrogen generation reactions
Implementation Method 2
heat-treating an applied material not containing any chlorine atom prepared by dissolving lanthanum carboxylate in a nitric acid solution of ruthenium nitrate at temperature within a range from 400° C to 600° C in an oxygen containing atmosphere
Data Source
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AI summary
An electrode for hydrogen generation can maintain a low hydrogen overvoltage for a long period of time even when electrolysis is conducted there not only with a low current density but also with a high current density. The electrode for hydrogen generation has a coating layer formed on a conductive base member by applying a material not containing any chlorine atom prepared by dissolving lanthanum carboxylate in a nitric acid solution of ruthenium nitrate and thermally decomposing the material in an oxygen-containing atmosphere.