Nickel Electrode Activity Restoration via Platinum Catholyte Metering
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Solution Overview
Problem
Noble-metal-coated nickel electrodes used in sodium chloride electrolysis experience decreased performance over time, leading to increased cell voltage, which requires complex and costly maintenance procedures, including electrode removal and recoating, and the addition of iron compounds can disrupt the electrolysis process.
Innovation Solution
Metering a water-soluble platinum compound, such as hexachloroplatinic acid or sodium hexachloroplatinate, into the catholyte during ongoing electrolysis at reduced current density and specific temperature conditions to maintain electrode activity without interrupting the process and prevent platinum loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nickel electrodes are coated with noble metals or noble metal oxides to improve hydrogen evolution performance, then electrode activity is improved, but the coating degrades over time requiring complex recoating procedures
Solution Approach 1:
The patent implements self-service by enabling the electrode coating to self-regenerate during operation. Platinum compounds are added to the electrolyte, where they automatically deposit onto the nickel electrode surface during electrolysis, restoring the coating without external intervention or shutdown
Solution Approach 2:
The patent achieves continuity of useful action by allowing the coating regeneration process to occur during ongoing electrolysis operations. The electrode maintains its catalytic activity continuously as platinum compounds are deposited during normal operation, eliminating shutdown periods
2Use of energy by moving object
If iron compounds are added to the catholyte to lower cell voltage, then energy consumption is reduced, but the electrolysis process is disrupted and cell voltage increases
Solution Approach 1:
The patent applies parameter changes by switching from iron-based additives to platinum-based compounds. This chemical parameter change fundamentally alters the interaction mechanism: platinum compounds deposit on the electrode surface to enhance catalysis without disrupting the electrolysis process, whereas iron compounds caused harmful effects
Solution Approach 2:
The patent uses inexpensive platinum compounds (such as platinum chloride or platinum sulfate) that can be continuously added to the electrolyte. These compounds serve their purpose by depositing platinum onto the electrode and are then consumed or removed, allowing continuous regeneration without long-term stability requirements
3Reliability
If electrode recoating is performed to restore performance, then electrode activity is improved, but production is interrupted and time is lost
Solution Approach 1:
The patent achieves continuity of useful action by enabling coating regeneration during ongoing electrolysis operations. The electrode maintains its catalytic activity continuously as platinum compounds are deposited during normal operation, eliminating shutdown periods for maintenance
Solution Approach 2:
The patent applies preliminary action by pre-loading platinum compounds into the electrolyte before electrolysis begins. These compounds are readily available during operation, allowing immediate deposition onto the electrode surface when performance degradation occurs, without requiring external preparation or shutdown
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
This method reduces cell voltage and maintains electrode performance without the need for frequent shutdowns or recoating, ensuring continuous operation and reducing energy consumption and maintenance costs.
Implementation Method 1
a water-soluble platinum compound... is metered into the catholyte during the electrolysis... to improve the activity of the electrode
Implementation Method 2
electrolysis of sodium chloride... a water-soluble platinum compound... is metered into the catholyte during the electrolysis
Data Source
AI summary
The invention relates to a method for improving the performance of coated nickel electrodes in alkali chloride electrolysis by adding water-soluble platinum compounds to the catholyte during electrolysis at low current density.