Iridium Oxide Network on Non-conductive TiO2 Support as a Catalyst for Oxygen Evolution Reaction

Abstract

Successful deployment of hydrogen technologies relies on converting electricity from renewable energy sources into hydrogen. Proton exchange membrane electrolyzers are currently the technology of choice for this transformation. These devices use electricity to split water molecules into hydrogen and oxygen. To build membrane electrode assemblies with low iridium loading, while maintaining good in-plane conductivity, an extended network of iridium oxide is required. To this effect, we synthesize IrO2 catalysts on a non-conductive titanium dioxide anatase support. The iridium oxide particles obtained are well dispersed on the surface of the support. Furthermore, at the optimal iridium oxide loading, a network of relatively small iridium oxide particles covers the surface of the support. Increasing the iridium oxide loading beyond this optimum does not bring any appreciable increase in connectivity and decreases the surface-to-mass ratio of iridium oxide, which is detrimental to the mass activity of the material. The synthesis method presented herein leads to the formation of an iridium oxide extended network that grants electrical conductivity to the material despite the high resistivity of the titanium dioxide anatase support. The result is a catalyst that enjoys the chemical stability of anatase but is also conductive and highly active for the OER.