Electrolyte-Free Electrosynthesis of Pure H₂O₂ via Triple-Phase Interface Engineering

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Electrosynthesis of hydrogen peroxide (H2O2) via proton exchange membrane electrolyzers is a promising decentralized production method.
• Conventional methods struggle with managing the gas-liquid-solid interface for optimal O2 supply and H2O2 removal.

Purpose of the Study:

• To develop an improved strategy for H2O2 electrosynthesis by engineering the triple-phase interface.
• To enhance the efficiency and stability of on-demand H2O2 production for practical applications.

Main Methods:

• Integration of a 3D hydrophobic grid gas diffusion electrode (GDE) with gas-liquid two-phase flow.
• Utilizing simulations to understand the impact of fluid dynamics on mass transport.
• Coupling the electrosynthesis system with a microfluidic unit for pollutant degradation studies.

Main Results:

• Achieved a peak Faradaic efficiency (FE) of 84.6% at -10.0 mA cm-2 using deionized water.
• Simulations indicated enhanced O2 transport via bubble wake vortices and accelerated H2O2 transport through shear-driven convection.
• Demonstrated sustained FE above 60% for 50 hours in organic pollutant degradation, with tunable H2O2 concentrations from 153.6 to 2443.7 mg L-1.

Conclusions:

• The engineered triple-phase interface strategy significantly improves H2O2 electrosynthesis.
• The scalable and flexible system offers a robust platform for sustainable, on-demand chemical production and application.