Nitrogen-Rich Conjugated Microporous Polymers with Improved Cobalt(II) Density for Highly Efficient Electrocatalytic...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The oxygen evolution reaction (OER) is crucial for energy devices but is hindered by sluggish kinetics.
• Developing efficient oxygen evolution catalysts (OECs) from earth-abundant elements is a key challenge.

Purpose of the Study:

• To design and synthesize a novel conjugated microporous polymer (CMP) with abundant coordination sites for OER.
• To investigate the OER performance of the synthesized CMP-based catalyst and understand the role of cobalt incorporation.

Main Methods:

• Synthesis of conjugated microporous polymers (CMPs) by coupling TBPT with Co(II) porphyrin.
• Further metallization of CMP-Py(Co) with Co2+ ions to yield CMP-Py(Co)@Co.
• Electrochemical characterization of OER activity, including overpotential and Tafel slope measurements.
• Density functional theory (DFT) calculations to elucidate catalytic mechanisms.

Main Results:

• CMP-Py(Co)@Co demonstrated excellent OER activity with a low overpotential (285 mV vs RHE) and Tafel slope (80.1 mV dec-1).
• The catalyst exhibited higher Co2+ content and water affinity compared to CMP-Py(Co).
• CMP-Py(Co)@Co outperformed benchmark RuO2 and most reported porous organic polymer-based OECs.

Conclusions:

• The enhanced OER activity is attributed to the incorporation of Co2+ ions, creating rich active sites and increasing electrochemical surface area.
• Co2+-TBPT sites were found to be more active than Co2+-porphyrin sites for OER via DFT calculations.
• Developing CMPs with abundant metal sites offers a promising strategy for designing efficient OECs.