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Co/Fe Bimetallic Coordination Polymers as Electrocatalysts for Oxygen Evolution and Urea Oxidation: Influence of
Litun Kumar Pradhan1,2,3, Ranjay K Tiwari1,2,3, Sanjana Madapura Suresh4
1School of Chemical Sciences, National Institute of Science Education and Research (NISER)), Jatni, Khurda, Bhubaneswar, Odisha 752050, India.
Abstract:
The development of efficient and durable electrocatalysts for the oxygen evolution reaction (OER) and urea oxidation reaction (UOR) is critical for advancing water electrolysis (WE) and urea electrolysis (UE). Herein, a series of one-dimensional Co/Fe bimetallic coordination polymers (CPs), formulated as [(CH3)2NH2]2[Co1-xFex(SO4)(C4N2H4)2(H2O)3]·H2O·SO4, were synthesized via a facile solvothermal route. The materials were evaluated as electrocatalysts for OER and UOR in alkaline media using a glassy carbon electrode. Among the series, Co0.3Fe0.7-CP exhibits the most superior OER activity, delivering a current density of 10 mA cm-2 at an overpotential of 270 mV, along with excellent operational stability over 70 h in 1.0 M KOH. Notably, the OER performance is significantly enhanced under an external magnetic field, where the overpotential required to achieve 50 mA cm-2 decreases from 350 to 310 mV as the magnetic field strength increases from 0 to 2000 G. For UOR, the optimized Co0.3Fe0.7-CP achieves a current density of 10 mA cm-2 at a low potential of 1.44 V vs RHE in 1.0 M KOH containing 0.33 M urea. These findings demonstrate that compositional tuning of bimetallic CPs, combined with magnetic-field-assisted electrocatalysis, represents an effective strategy for enhancing OER and UOR performance in alkaline energy conversion.
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