Condensation Center Regulation in Donor-Acceptor Polymers Enables Dynamic Proton Reservoirs for Efficient H₂O₂...

Area of Science:

• Materials Science
• Photocatalysis
• Renewable Energy

Background:

• Photocatalytic hydrogen peroxide (H₂O₂) production is a key solar-to-chemical energy conversion strategy.
• Limited control over structure-reactivity relationships in organic photocatalysts hinders efficiency.
• Developing stable and efficient organic photocatalysts is crucial for artificial photosynthesis.

Purpose of the Study:

• To design and synthesize diazine-based donor-acceptor (D-A) imine-linked covalent organic polymers (COPs) for efficient H₂O₂ generation.
• To investigate the impact of condensation center regulation on photocatalytic performance and stability.
• To elucidate the reaction mechanisms and identify key factors for optimizing H₂O₂ production.

Main Methods:

• Synthesis of D-A imine-linked COPs with varying condensation centers (para, meta, ortho).
• Photocatalytic H₂O₂ production experiments under simulated solar irradiation.
• Mechanistic studies including theoretical calculations and in-situ analyses.
• Evaluation of structural stability and pH adaptability.

Main Results:

• Para-regulated COPs exhibited superior structural stability and photocatalytic activity.
• H₂O₂ generation was dominated by indirect 2e^- oxygen reduction reaction (ORR) and complemented by 4e^- water oxidation reaction (WOR).
• Localized protonation and para-regulation with -CN incorporation lowered energy barriers and enhanced interfacial electron transfer, improving efficiency and pH adaptability.

Conclusions:

• Condensation center regulation is a critical design principle for tuning structure-reactivity in COPs.
• The developed para-regulated COPs offer a promising platform for efficient and stable solar-driven H₂O₂ production.
• Understanding reaction mechanisms, including proton dynamics and electron transfer, is essential for advancing artificial photosynthesis.