Polyhydroxyurethane/Cobalt Nanocomposites as Green Non‐PGM Electrocatalysts for OER

Abstract Developing low‐cost, efficient non‐platinum group metal (non‐PGM) electrocatalysts for the oxygen evolution reaction (OER) is critical for advancing green hydrogen production. In search of such a non‐PGM catalyst, in this study, biodegradable polyhydroxyurethane (PHU) and cobalt salt nanocomposites were developed as green OER electrocatalysts for alkaline conditions (pH ∼13). Various amino acid‐based PHUs were blended with cobalt salt and sodium alginate (NaAL), yielding non‐PGM electrocatalysts ( PHU1–PHU6 ). NaAL enhanced catalytic performance by improving ion and mass transport at the PHU‐alginate interface. The hybrid catalysts exhibited superior OER activity, with PHU6 achieving a current density of 32 mA/cm 2 at 1.58 V, outperforming the benchmark RuO₂ (17 mA/cm 2 at 1.45 V) and CoO x (12 mA/cm 2 at 1.53 V). PHU6 also demonstrated a lower Tafel slope (102 mV/dec), higher electrochemical surface area (53 cm 2 ), double‐layer capacitance (1.32 mF), and similar overpotential (239 mV @ 10 mA/cm 2 ) compared to RuO₂ and CoO x . Its Faradic efficiency (∼80%) surpassed RuO₂ (76%) and CoO x (73%). The structure of PHUs significantly influenced these electrochemical parameters, showcasing PHU6 ’s promise as a cost‐effective, sustainable OER catalyst with excellent performance and stability.