Towards Stable and Conductive Titanium Oxynitride High-Surface-Area Support for Iridium Nanoparticles as Oxygen Evolution Reaction Electrocatalyst

The rational design of electrochemical oxygen evolution reaction (OER) electrocatalyst is essential for the development of efficient and sustainable electrochemical energy conversion, storage and electrolysis applications. One of the remaining limitations of the low-temperature electrolyzers is the large amounts of highly scarce and expensive iridium used as the OER electrocatalysts. This could be solved by applying much smaller amounts of iridium on efficient and stable support. Here we present a very promising functionality of titanium oxynitride (TiONx) high-surface-area support that effectively disperses the iridium nanoparticles, exhibits good intrinsic electrical conductivity and stability and thus promises efficient reduction of the noble-metal loading in electrolyzers gas diffusion electrodes. The new nanocomposite made of approximately 3 nm-sized iridium nanoparticles finely dispersed on TiONx support is produced using a novel synthetic route. Extensive characterization shows that the new composites exhibit an electronic interaction with the support and, ultimately, a high OER performance in acidic media.