Ru-core Ir-shell electrocatalysts deposited on a surface-modified Ti-based porous transport layer for polymer electrolyte membrane water electrolysis

Novel Ru-core Ir-shell catalyst-integrated porous transport electrodes (PTEs) for polymer electrolyte membrane water electrolysis (PEMWE) cells are prepared, in which Ru-core Ir-shell catalyst nanostructures are directly deposited onto a porous transport layer (PTL) via arc plasma deposition (APD). The PTL has a nanostructured TiO₂ surface prepared via NaOH etching, acting as a catalyst support. The performance and durability of these Ru-core Ir-shell catalysts depend strongly on the ratio of Ir and Ru. The current-voltage (I–V) characteristics of PEMWE cells were improved by applying these core-shell catalysts with a low Ir loading of around 0.1 mg cm⁻². The core-shell catalyst-integrated PTEs can operate at current densities of up to 10 A cm⁻² without exhibiting limiting current behavior. This unique combination of the core-shell catalyst and the PTE structure enables PEMWE cell operation with low iridium loading and high current density, potentially reducing the cost of green hydrogen.