Photoelectrochemical Glycerol Valorization Achieving an Internal Quantum Efficiency Over 180% via Current Doubling

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Photoelectrochemical (PEC) systems face challenges in achieving high efficiency, stability, and cost-effectiveness.
• Oxidizing organic molecules instead of water offers a route to enhance hydrogen production and create valuable byproducts.

Purpose of the Study:

• To develop an efficient PEC system for glycerol oxidation, aiming for current doubling and high hydrogen production efficiency.
• To investigate the role of Mo, N co-doping in BiVO4 photoanodes and NaClO4 electrolyte in enhancing PEC performance.

Main Methods:

• Fabrication of Mo, N co-doped BiVO4 photoanodes.
• Electrochemical and photoelectrochemical characterization in NaClO4 electrolyte.
• Density Functional Theory (DFT) calculations to understand reaction mechanisms.

Main Results:

• Achieved a record photocurrent density of 9.73 mA cm⁻² at 1.23 V vs RHE.
• Reached a maximum internal quantum efficiency of 182% with stable performance over 500 hours.
• Demonstrated C-C cleavage products (glycolaldehyde, formaldehyde) from glycerol oxidation.

Conclusions:

• The optimized PEC system effectively utilizes glycerol oxidation for efficient hydrogen production and valorization.
• Co-doping and electrolyte choice significantly improve charge separation, transport, and reaction kinetics.
• The system shows potential for recycling waste plastics and valorizing platform molecules.