Iridium–Nickel\nNanoparticle-Based Aerogels\nfor Oxygen Evolution Reaction

Abstract

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