Cobalt-doped IrRu bifunctional nanocrystals for reversal-tolerant anodes in proton-exchange membrane fuel cells

Abstract

Ir-Ru alloy has been regarded as a promising multi-functional catalyst for reversal-tolerant anodes (RTA) in proton-exchange membrane fuel cells (PEMFCs). In order to further promote its application for RTA catalysts in PEMFCs, we develop a carbon-supported cobalt-doped IrRu (Co-IrRu/C) catalysts by polyol method under weak acidic conditions in the absence of surfactant. The density functional theory (DFT) results indicate that Co will change the electronic state on the surface of Ir and Ru, weaken the adsorption energies of reaction intermediates and reduce the barrier of reaction path for HOR and OER, and thus improve the catalytic activity of Co-IrRu/C. The obtained Co-IrRu/C-2 shows high HOR activity (7.88 mA/cm2@25 mV), OER activity (248 mV@10 mA/cm2), MEA performance (0.466 V@2 A/cm2) and RTA performance (14.9 min), which are obviously superior to IrRu/C (OER activity, 326 mV@10 mA/cm2, RTA performance, 10.6 min) and Pt/C (HOR activity, 7.76 mA/cm2@25 mV, RTA performance, 0.75 min). This work can promote the application of multi-functional Co-IrRu alloys as RTA catalysts in PEMFCs and thus replace conventional Pt/C catalysts.