Cobalt-Based Coordination Polymer for Oxygen Reduction Reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Designing efficient electrocatalysts for oxygen reduction reaction (ORR) is hindered by challenges in controlling coordination polymer (CP) structure and electrical properties.
• Developing active, stable, and cost-effective ORR electrocatalysts is crucial for advancing fuel cell technology.

Purpose of the Study:

• To synthesize and characterize a novel semiconductive coordination polymer (CP) with a low-optical band gap for high-performance ORR.
• To investigate the electrocatalytic activity of the synthesized CP in alkaline media.
• To elucidate the structural and electronic factors contributing to the ORR performance of the CP.

Main Methods:

• Synthesis of a new cobalt-based coordination polymer (CP), denoted as compound 1: [{Co3(μ3-OH)(BTB)2(BPE)2}{Co0.5N(C5H5)}].
• Characterization of electrical conductivity using impedance spectroscopy (5 × 10⁻⁴ S cm⁻¹).
• Electrochemical evaluation of ORR activity using cyclic voltammetry, rotating disk electrode, and rotating ring-disk electrode techniques on Ketjenblack EC-600JD carbon support.
• Theoretical calculations to predict active catalytic sites and electronic interactions.

Main Results:

• The synthesized CP exhibits high-performance ORR in an alkaline medium.
• Compound 1 demonstrates a facile 3.6-electron ORR process, efficiently reducing O2 to H2O.
• Theoretical calculations indicate that the monomeric cobalt center is the active site for ORR due to favorable molecular orbital overlap with O2.

Conclusions:

• The novel semiconductive CP, compound 1, offers a promising, cost-effective alternative to platinum catalysts for ORR.
• Its high efficiency and low cost make it a suitable cathode material for fuel cells.
• This work highlights the potential of rationally designed CPs as advanced electrocatalysts for energy conversion applications.