Alkaline Ammonia Electrolysis Cell Pulse Voltage for Catalyst Poisoning
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Solution Overview
Problem
The high overvoltage and surface poisoning of platinum catalysts in Ammonia Electrolysis Cells (AECs) due to reaction intermediates, leading to significant activity loss and corrosion issues with conventional materials.
Innovation Solution
Implementing an Anode & Cathode Pulse Sequence Method with specific voltage and rest periods to remove poisoning species (*NHx and OH−) and using corrosion-resistant materials like Ni and epoxy for the separator and end plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If platinum catalyst is used for ammonia oxidation reaction, then catalytic activity is improved, but electrode surface poisoning occurs due to strong adhesion of reaction intermediates
Solution Approach 1:
The patent applies periodic voltage cycling between anodic and cathodic potentials to the platinum electrode. During the anodic phase, poisoning species are oxidized and removed from the surface. During the cathodic phase, the surface is reduced and prepared for the next reaction cycle. This periodic electrical treatment prevents cumulative surface poisoning while maintaining catalytic activity.
Solution Approach 2:
The patent changes the electrical potential parameter applied to the electrode by cycling between positive (anodic) and negative (cathodic) voltages. This dynamic parameter change allows the electrode surface to alternately undergo oxidation (removing poisons) and reduction (preparing for reaction), thereby preventing surface poisoning while maintaining activity.
2Ease of manufacture
If conventional materials (aluminum, carbon, rubber) are used in AEC, then ease of manufacture is improved, but corrosion resistance deteriorates due to high corrosiveness of ammonia
Solution Approach 1:
The patent employs composite material construction where conventional materials (aluminum end plates, carbon separator, rubber gaskets) are combined with corrosion-resistant coatings or protective layers. This composite approach allows the system to benefit from the ease of manufacturing conventional materials while gaining the corrosion resistance needed for ammonia electrolysis environments.
Solution Approach 2:
The patent introduces intermediary protective layers or coatings between the conventional structural materials and the corrosive ammonia electrolyte. These intermediary layers act as barriers that prevent direct contact between the corrosive ammonia and susceptible materials like aluminum and rubber, thereby maintaining both manufacturability and corrosion resistance.
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
Significantly reduces reaction current density and improves durability by preventing electrode surface poisoning, enabling efficient hydrogen production from ammonia.
Implementation Method 1
The voltage driving part may apply a driving voltage for a first period and a rest voltage for a second time period between the first and second collector plates to remove *NHx and OH−
Implementation Method 2
The Ammonia Electrolysis Cell (AEC), utilizing an electrochemical technique for hydrogen extraction, involves the Ammonia Oxidation Reaction (AOR, NH3 into N2) at the oxidation electrode and the Hydrogen Evolution Reaction (HER, Water into H2) at the reduction electrode
Data Source
AI summary
An ammonia electrolysis cell according to one embodiment of the present invention includes an end plate, a collector plate, a separator plate, a porous transport layer support gasket, a porous transport layer electrode, and a membrane, wherein the collector plate is connected to a power source, the power source may be characterized in that it cross-applies a working voltage and a rest voltage of 0.2 V or less. Thus, the present invention can effectively remove* NHx and OH− that poison the oxidation electrode, thereby significantly increasing the efficiency of hydrogen production, and can provide a bulk storage and transportation device for utilizing hydrogen as an energy medium.