Tandem Photoelectrochemical Cells for Hydrogen Peroxide With Glyceric Acid Production.

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Photoelectrochemical (PEC) oxygen reduction offers a sustainable route for hydrogen peroxide (H₂O₂) production, but faces challenges in long-term stability and efficiency.
• Existing methods like the anthraquinone process are energy-intensive and environmentally detrimental.
• Sluggish charge transfer kinetics and poor photoelectrode corrosion resistance hinder stable PEC operation.

Purpose of the Study:

• To develop a highly efficient and stable photocathode for solar-driven hydrogen peroxide (H₂O₂) generation.
• To construct a bias-free PEC system for simultaneous H₂O₂ production and glycerol valorization.
• To evaluate the system's performance in producing high-value chemicals and its application in water disinfection.

Main Methods:

• Synthesis of a heterojunction photocathode: CuO and W-doped CuBi₂O₄ decorated with Pd nanoparticles (Pd:CuO/W-CBO).
• Construction of a bias-free PEC system using the developed photocathode and a Pt/TiOₓ anode.
• Optimization of glycerol oxidation selectivity using an anion exchange membrane.
• Assessment of H₂O₂ efficacy for water disinfection.

Main Results:

• The optimized Pd:CuO/W-CBO photocathode achieved >90% Faradaic efficiency for H₂O₂ production with a low onset potential (1.08 V_RHE) and stable operation (>50 h).
• The bias-free PEC system demonstrated a solar-driven current density of 3.75 mA cm⁻² for simultaneous H₂O₂ and C₃ chemical production.
• Anion exchange membrane enhanced selectivity to 56% for glyceric acid production from glycerol.
• Cathodically generated H₂O₂ achieved >99.9% bacterial inactivation within 180 min.

Conclusions:

• The developed Pd:CuO/W-CBO photocathode provides an efficient and stable platform for solar-driven H₂O₂ generation.
• The integrated PEC system enables simultaneous valorization of glycerol into high-value chemicals and effective water disinfection.
• This work demonstrates a scalable and sustainable approach for energy conversion and chemical production.