Directional Electron Transfer in Island-Sea Structured Contact-Electro-Catalysis Enables Cascade Defluorination of...

Area of Science:

• Materials Science
• Environmental Chemistry
• Catalysis

Background:

• Per- and polyfluoroalkyl substances (PFAS) exhibit exceptional C─F bond stability, resisting conventional degradation methods.
• Contact-Electro-Catalysis (CEC) offers an oxidant-free approach but faces challenges with electronic structure control and electron transfer directionality.

Purpose of the Study:

• To design an advanced CEC system for effective PFAS degradation.
• To engineer interfacial electron dynamics for enhanced catalytic activity.

Main Methods:

• Fabrication of an "island-sea" structured CEC system with atomically dispersed Cu─N₄ islands in a PVDF matrix.
• Induction of β-phase crystallization in PVDF to amplify piezoelectric polarization and interfacial electric fields (IEFs).
• Utilizing field-emission-driven electron injection into Cu─N₄ sites for O₂ activation and C─F bond cleavage.

Main Results:

• Achieved 95% degradation and 94.4% defluorination of perfluorooctanoic acid (PFOA).
• Demonstrated efficient electron harvesting from water and targeted electron injection into Cu─N₄ sites.
• Established a cascade redox pathway involving superoxide radical anions (^•O₂ ^-), hydroxyl radicals (^•OH), and singlet oxygen (¹O₂).

Conclusions:

• The "island-sea" CEC system with β-phase PVDF effectively degrades PFAS via a cooperative mechanism.
• β-phase-mediated IEF engineering in polymer/single-atom hybrids is a viable strategy for directing interfacial electron dynamics.
• This approach offers a stable and efficient method for tackling persistent organic pollutants.