Facile preparation of core-shell Ru@Ir/C catalyst as a bifunctional electrocatalyst for reversal-tolerant anode in polymer electrolyte membrane fuel cell

Abstract

A robust bifunctional electrocatalyst capable of facilitating both the hydrogen oxidation reaction (HOR) and oxygen evolution reaction (OER) is essential for addressing carbon oxidation issues at the anode during cell reversal conditions in polymer electrolyte membrane fuel cell systems. In this study, we explore a bifunctional Ru@Ir/C core-shell electrocatalyst with different Ru:Ir ratios to assess its performance in both HOR and OER. The core-shell architecture of Ru@Ir is easily fabricated via sequential methods involving the formation of Ru nanoparticles onto carbon support by a solid-state method using resonance acoustic mixing, followed by the deposition of Ir shells onto the preformed Ru core using a simple ethanol reduction technique. The line-scanning profile of the energy-dispersive spectrum in transmission electron microscopy confirms the core-shell structure of Ru@Ir/C, which consists of Ru core and Ir shell. The synthesized Ru@Ir/C showed better OER performance than Ru/C and Ir/C while demonstrating comparable HOR performance to Ir/C and Pt/C. Furthermore, the presence of the Ir shell enhances active site availability for both OER and HOR, along with improved stability attributed to the electronic effects arising from the lattice mismatch between Ru and Ir.