Durability and Degradation Analysis of CoFe2O4 Supported on Carbon Nitride Composites for Alkaline Oxygen Evolution Reaction

This study investigates the oxygen evolution reaction (OER) performance and degradation mechanisms of CoFe2O4 (CFO) and its composite with carbon nitride (CFO/CN). The CFO/CN electrocatalyst exhibits superior initial catalytic activity, achieving a higher current density (42 mA cm-2 at 1.58 V vs. RHE), lower overpotential (359 mV at 10 mA cm-2), and a smaller Tafel slope (45.2 mV/dec) due to enhanced charge transfer, oxygen vacancy stabilization, and pseudocapacitive contributions from CN. However, prolonged cycling leads to structural degradation, oxygen vacancy depletion, and surface amorphization, resulting in performance decline. Despite this, CFO/CN maintains better stability at 10 mA cm-2, sustaining a lower operating voltage than CFO over 24 hours. Post-OER XRD and XPS confirm that CN mitigates severe catalyst degradation, preserving active sites and conductivity. These findings show that while higher activity can be achieved, maintaining long-term stability remains a challenge, highlighting the importance of developing strategies to preserve oxygen vacancies and strengthen the catalyst’s structure for sustained OER performance.