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Chirality-Induced Selective Electrosynthesis Hydrogen Peroxide and Tandem Green Chemical Synthesis
Boying Zhang1, Haochuan Li1, Ruijuan Zhang2
1College of Chemistry and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, China.
Angewandte Chemie (International Ed. in English)
|August 12, 2026
Summary
Chiral Salen covalent organic frameworks utilize the chirality-induced spin selectivity effect to enhance the two-electron oxygen reduction reaction, significantly boosting hydrogen peroxide production. This breakthrough overcomes spin-forbidden transitions, enabling efficient H2O2 generation for various applications.
Area of Science:
- Electrochemistry
- Materials Science
- Catalysis
Background:
- The two-electron oxygen reduction reaction (2e--ORR) to hydrogen peroxide (H2O2) is hindered by slow O─O bond preservation and the spin-forbidden transition of triplet O2 to singlet H2O2.
- Efficient H2O2 generation is crucial for applications in chemical synthesis and advanced oxidation processes.
Purpose of the Study:
- To address the challenges in 2e--ORR by employing chiral Salen covalent organic frameworks (C-Salen-COFs-Zn) that leverage the chirality-induced spin selectivity (CISS) effect.
- To investigate the mechanism by which CISS enhances H2O2 selectivity and production rates.
Main Methods:
- Synthesis of inherently chiral Salen covalent organic frameworks (C-Salen-COFs-Zn).
- Electrocatalytic evaluation of C-Salen-COFs-Zn for the 2e--ORR in an H-type cell and a flow-cell system.
- Mechanistic studies including adsorption mode analysis and spin polarization efficiency determination.
Main Results:
- C-Salen-COFs-Zn demonstrated high spin selectivity (>90% CISS-induced spin polarization efficiency), outperforming achiral counterparts.
- Achieved 87.0% H2O2 selectivity and high production rates (297.7 mmol g-1 h-1 at 0.2 V vs RHE) in an H-type cell, with up to 93.7% Faradaic efficiency at 0.6 V vs RHE.
- Flow-cell system yielded significantly higher H2O2 production (1169.7–1207.6 mmol g-1 h-1).
- Mechanistic studies indicated a Pauling-type adsorption mode favoring •O2- formation and O─O bond preservation.
- Integrated C-Salen-COF-Zn into a cascade system for on-demand H2O2 generation and utilization, achieving high conversions in sodium perborate synthesis, sodium peroxycarbonate synthesis, lignin conversion, and electro-Fenton degradation.
Conclusions:
- The CISS effect in C-Salen-COFs-Zn effectively alleviates the spin-forbidden transition in 2e--ORR, promoting efficient H2O2 generation.
- These chiral electrocatalysts offer a promising strategy for selective and efficient H2O2 production.
- The successful integration into a cascade system highlights the potential for practical applications in synthesis and environmental remediation.
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