Illuminating the Interface: In Situ Optical Insights Into Two-Electron ORR Pathways for H₂O₂ Electrosynthesis

Area of Science:

• Electrochemistry
• Materials Science
• Spectroscopy

Background:

• Hydrogen peroxide (H2O2) is a green oxidant with growing importance.
• Electrosynthesis of H2O2 via the two-electron oxygen reduction reaction (2e- ORR) offers a sustainable alternative to the anthraquinone process.
• Understanding interfacial active sites is critical for efficient H2O2 electrosynthesis.

Purpose of the Study:

• To systematically review in situ optical characterization methods for H2O2 electrosynthesis via 2e- ORR.
• To elucidate interfacial mechanisms and reaction principles for scalable H2O2 production.
• To highlight advancements in spatial resolution and reaction information accessible through optical techniques.

Main Methods:

• Review of one-dimensional (1D) spectroscopy.
• Review of two-dimensional (2D) imaging.
• Review of three-dimensional (3D) reaction-field imaging and multimodal coupling.

Main Results:

• In situ optical methods provide crucial insights into interfacial processes during H2O2 electrosynthesis.
• Progressive enhancement in spatial resolution and accessible reaction information is demonstrated.
• Correlation of optical, electrochemical, and structural data aids mechanistic understanding.

Conclusions:

• In situ optical characterization is essential for advancing H2O2 electrosynthesis technology.
• These methods facilitate the development of sustainable and economically viable H2O2 production.
• Future innovation in optical techniques will support green industry and carbon neutrality goals.