Investigation of growth mechanism for non-precious Co nanostructures as highly efficient electrocatalysts for hydrogen and oxygen evolution reaction

Cobalt nanoparticles with controlled morphology were synthesized via a tunable heating-rate approach and evaluated for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysis. Cyclic voltammetry studies revealed that the nanoparticles remain electrochemically stable up to –1.5 V, with well-defined cathodic and anodic redox peaks corresponding to the Co2⁺/Co redox couple. Among the synthesized samples, those prepared at the lowest heating rate (5 °C h⁻1) exhibited s