Platinized Titanium as Alternative Cost-Effective Anode for Efficient Kolbe Electrolysis in Aqueous Electrolyte...

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Energy

Background:

• Kolbe electrolysis is a method for electrochemical conversion of carboxylic acids.
• Developing efficient and cost-effective electrocatalysts is crucial for sustainable chemical synthesis.
• n-hexanoic acid conversion offers a pathway to valuable chemical products and liquid fuels.

Purpose of the Study:

• To evaluate commercial materials for electrochemical conversion of n-hexanoic acid using Kolbe electrolysis.
• To identify the most efficient electrode material for this process.
• To analyze the factors influencing electrode performance and cost-effectiveness.

Main Methods:

• Kolbe electrolysis of n-hexanoic acid.
• Assessment of five commercial electrode materials.
• Characterization using optical profilometry, scanning electron microscopy, and energy-dispersive X-ray spectroscopy.
• Coulombic efficiency measurements.

Main Results:

• Platinized titanium demonstrated superior performance, achieving 93.1% coulombic efficiency for n-hexanoic acid degradation and 48.3% for n-decane production.
• Performance was comparable to pure platinum electrodes.
• Surface coverage of platinum on titanium was identified as critical for efficiency; 1-3% uncovered surface reduced efficiency by ~50%.
• Production yielded 56.7 mL of liquid fuel per mole of n-hexanoic acid, with an energy demand of 6.66 kWh/L and cost of €1.22/L.
• Platinized titanium offers >36x lower capital expenditure and <10% increased operational expenditure compared to alternatives.
• An electrode lifetime of 10,000 hours is projected.

Conclusions:

• Platinized titanium is a highly effective and economical electrode material for the Kolbe electrolysis of n-hexanoic acid.
• Optimizing platinum coverage on titanium is key to maximizing coulombic efficiency.
• This technology presents a viable route for sustainable liquid fuel and chemical production with significant cost and performance advantages.