Kinetics and electrocatalytic activity of IrCo/C catalysts for oxygen reduction reaction in PEMFC

The purpose of this study is to develop a novel binary Iridium-Cobalt/C catalyst as a suitable substitute for platinum/C applied in proton exchange membrane fuel cells (PEMFCs). The carbon-supported IrCo catalysts were successfully synthesized using IrCl3 and C4H6CoO4 as the Ir and Co precursors respectively, in ethylene glycol (EG) refluxing at 120 °C. The nanostructured catalysts were characterized by X-ray diffraction (XRD) and high-resolution transmission electron microscope (TEM). Homogeneous catalyst particles supported on carbon showed a size of proximately 2 nm. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were conducted for the characterization of the catalyst performances. With a cathodic loading of 0.4 mgIr cm−2, 20%Ir-30%Co/C achieved a maximum power density of 501.6 mW cm−2 at 0.418 V, with a 50 cm2 H2/O2 single cell. Although such a performance is about 26% lower than commercial Pt/C catalyst, it is still helpful in terms of Pt replacement and cost reduction.

► IrCo/C nanoparticles fabricated by a modified ethylene glycol (EG) reduction method.
► Effect of different atomic ratios of Ir and Co in precursor solutions investigated.
► IrCo/C nanoparticles demonstrate excellent oxygen reduction reaction activity, through an approximate four-electron pathway.
► Novel IrCo/C nanoparticle catalysts synthesized would be very promising for PEMFC.