Electrode-assisted catalytic water oxidation by a flavin derivative

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Solar fuel technologies require efficient catalysts for water oxidation.
• Current molecular water-oxidation catalysts predominantly use transition metals.

Purpose of the Study:

• To report the catalytic water oxidation activity of a fully organic compound.
• To explore an organic alternative to transition-metal-based water-oxidation catalysts.

Main Methods:

• Bulk electrolysis of aqueous N(5)-ethylflavinium ion (Et-Fl(+)) solutions.
• Spectroelectrochemical analysis.
• Preliminary density functional theory calculations.

Main Results:

• Oxygen evolution was detected during electrolysis of Et-Fl(+) solutions at potentials above +1.9 V.
• Catalysis occurred on glassy carbon and platinum electrodes, but not on fluoride-doped tin-oxide electrodes.
• A proposed mechanism involves a peroxide intermediate formed between the oxidized flavin pseudobase and the carbon electrode.

Conclusions:

• The N(5)-ethylflavinium ion demonstrates catalytic activity for water oxidation, producing oxygen.
• This organic compound presents a viable, metal-free alternative for water-oxidation catalysis.
• Findings pave the way for developing new classes of sustainable catalysts for solar fuel production.