Rhodium-Free Hypochlorous Acid Electrode With Composite Oxides
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Solution Overview
Problem
Existing hypochlorous acid generating electrodes containing rhodium oxide are expensive due to the scarcity and high cost of rhodium, and there is a need for a durable and efficient alternative that can generate hypochlorous acid from low chloride ion concentration water.
Innovation Solution
A hypochlorous acid generating electrode composed of a titanium substrate with a composite layer containing iridium, tantalum, and ruthenium or platinum, without rhodium oxide, which maintains performance and durability comparable to rhodium-containing electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rhodium oxide is used in the electrode composition, then the electrode can efficiently generate hypochlorous acid, but the production cost increases significantly due to the scarcity and high cost of rhodium
Solution Approach 1:
The invention changes the compositional parameters of the electrode catalyst layer by replacing rhodium oxide with a combination of iridium oxide, tantalum oxide, and ruthenium oxide in specific molar ratios (iridium oxide 20-80 mol%, tantalum oxide 20-80 mol%, ruthenium oxide 1-50 mol%). This parameter optimization maintains hypochlorous acid generation efficiency while eliminating dependence on expensive rhodium, thereby resolving the contradiction between productivity and manufacturing cost
Solution Approach 2:
The invention substitutes expensive rhodium oxide with more abundant and cost-effective metal oxides (iridium oxide, tantalum oxide, ruthenium oxide). Although these alternative materials have different durability characteristics, their combination in the specified composition range achieves both cost reduction and sustained operational effectiveness, addressing the cost concern without sacrificing long-term performance
2Productivity
If rhodium-containing electrodes are used, then good hypochlorous acid generation performance is achieved, but the durability and stability are insufficient
Solution Approach 1:
The invention creates a composite catalyst layer combining iridium oxide, tantalum oxide, and ruthenium oxide in specific proportions. This composite material approach leverages the complementary properties of each component: iridium oxide provides catalytic activity, tantalum oxide enhances structural stability, and ruthenium oxide improves electrical conductivity. The synergistic effect of this composite composition simultaneously achieves high hypochlorous acid generation efficiency and enhanced electrode durability, resolving the contradiction between productivity and reliability
Solution Approach 2:
The invention optimizes the local composition and distribution of metal oxides within the catalyst layer to achieve uniform performance across the electrode surface. By controlling the molar ratios and spatial distribution of iridium oxide, tantalum oxide, and ruthenium oxide, the electrode maintains consistent catalytic activity and structural integrity during prolonged operation, thereby improving reliability while preserving productivity
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 efficiently generates hypochlorous acid with concentrations of 0.2 ppm or more, maintains performance for over 500 hours, and operates effectively under high current densities, reducing production costs by replacing rhodium with less expensive metals.
Implementation Method 1
Electrolyzation of water that contains a chloride ion, e.g., tap water and well water, produces chlorine at an anode, and the chlorine with water produces hypochlorous acid water
Implementation Method 2
the electrode for generating hypochlorous acid by electrolyzing water that contains a chloride ion
Data Source
AI summary
Disclosed is a hypochlorous acid generating electrode that is substantially free from rhodium, which is comparable in performance to a rhodium-containing electrode and is more durable than the rhodium-containing electrode. The electrode to be used for generating hypochlorous acid by electrolyzing water that contains a chloride ion has excellent hypochlorous acid water generation ability and durability, in which the electrode has an electrode substrate comprising titanium or titanium alloy, and a composite layer that is electrically connected with the electrode substrate and that contains iridium or a compound thereof, tantalum or a compound thereof, and ruthenium or a compound thereof and/or platinum, and does not contain rhodium oxide.