Iridium–Nickel Nanoparticle-Based Aerogels for Oxygen Evolution Reaction

Iridium is considered the state-of-the-art electrocatalyst for the oxygen evolution reaction (OER) in acidic media owing to its considerably high activity and stability, yet it is a raw material that is expensive and rare. Here we present a synthesis of a bimetallic hollow aerogel structure based on iridium and nickel prepared by a very simple and environmentally friendly method. Our electrocatalyst was evaluated for the OER in a single electrolysis cell, and it showed an improvement in electrocatalytic performance over time, reaching the current density of commercial IrO2 after 500 h of the stability test, despite half the catalyst loading. Our innovative synthesis approach provides the flexibility to tailor and improve the aerogel structures for other electrochemical devices as well, for example, photoelectrolysis, sensors, and more. In addition, we believe that this study can lead to a better understanding of the fundamental behavior of bimetallic electrocatalysts consisting of mixed compositions with transition metals.