Three-Dimensionally Interconnected Nanoporous IrRe Thin Films Prepared by Selective Etching of Re for Oxygen Evolution Reaction

Developing catalytically active, acid-stable, and electronically conductive catalysts is essential for efficient water electrolysis systems, but it is challenging to balance the three criteria properly. Herein, we report an enhanced balance between activity, stability, and conductivity of nanoporous IrRe thin films fabricated by selective etching of Re. The nanoporous IrRe thin film exhibited a 35 times higher activity–stability factor compared to the polycrystalline Ir due to its increased electrochemical active surface area and reconstructed structures by electrochemical dealloying of Re from IrRe. Furthermore, higher catalytic activities than the state-of-the-art nanoparticle IrO2 catalysts were achieved because of their higher electronic conductivity due to a unique morphology of a metallic core and an oxide shell. We highlight that the electrochemical dealloying is a promising approach to improve the catalytic performances simultaneously.