A closed-shell phenalenyl-based dinuclear iron(III) complex as a robust cathode for a one-compartment H₂O₂ fuel cell

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Closed-shell phenalenyl (PLY) systems are valuable for catalysts and electroactive materials due to their electron-accepting capabilities.
• Iron-based molecular complexes are being explored for energy conversion technologies.

Purpose of the Study:

• To synthesize and characterize a novel PLY-based dinuclear iron complex, [FeIII2(hmbh-PLY)3].
• To evaluate the utility of this complex as a cathode material in a hydrogen peroxide (H2O2) fuel cell.
• To investigate the catalytic mechanism of H2O2 reduction using DFT studies.

Main Methods:

• Synthesis of a new Schiff base ligand (hmbh-PLYH2) and its subsequent complexation with iron.
• Characterization using single-crystal X-ray diffraction (SCXRD).
• Electrochemical evaluation via cyclic voltammetry (CV) and performance testing in a H2O2 fuel cell.
• Density Functional Theory (DFT) calculations.

Main Results:

• The dinuclear iron complex [FeIII2(hmbh-PLY)3] was successfully synthesized and characterized.
• The complex exhibits five electron reductions, indicating significant electroactivity.
• The H2O2 fuel cell utilizing this complex as a cathode achieved a peak power density of 2.41 mW cm-2, outperforming previous Fe-based molecular complexes.
• DFT studies provided insights into the catalytic reduction of H2O2.

Conclusions:

• The novel PLY-based iron complex is a highly effective cathode material for H2O2 fuel cells.
• The complex demonstrates superior performance compared to existing iron-based molecular cathode materials.
• This research opens avenues for developing advanced electrocatalysts for energy applications.