Side-Chain Modification in Conjugated Polymer Frameworks for the Electrocatalytic Oxygen Evolution Reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Conjugated polymer frameworks (CPFs) show potential in photocatalysis, sensing, and energy storage.
• CPFs often lack solubility and processability due to their backbone structure.
• Metal-free electrocatalysts for oxygen evolution reaction (OER) are underexplored.

Purpose of the Study:

• To develop and investigate triazine-based donor-acceptor CPFs for metal-free electrocatalytic OER.
• To explore the impact of different sidechains (alkyl vs. oligoethylene glycol) on CPF electrocatalytic performance.
• To assess the OER activity, durability, and structure-property relationships of the synthesized CPFs.

Main Methods:

• Synthesis of two triazine-based donor-acceptor CPFs with varying sidechains (CPF1: hexyl, CPF2: oligoethylene glycol).
• Electrochemical characterization, including OER activity and durability testing.
• Density Functional Theory (DFT) calculations to support experimental findings.

Main Results:

• Both CPFs exhibited superior electrocatalytic OER activity and long-term durability.
• CPF2 (oligoethylene glycol sidechain) demonstrated significantly enhanced OER performance (10 mA/cm² at 328 mV overpotential) compared to CPF1 (488 mV).
• Porous nanostructure facilitated charge/mass transport; enhanced hydrophilicity and reduced π-π stacking in CPF2 contributed to its superior activity.

Conclusions:

• Metal-free CPFs are promising electrocatalysts for OER.
• Sidechain engineering, particularly with polar, hydrophilic groups like oligoethylene glycol, can substantially improve OER performance.
• Further modification of sidechains holds potential for optimizing CPF electrocatalysts for OER.