Ultralight conductive IrO2 nanostructured textile enables highly efficient hydrogen and oxygen evolution reaction: Importance of catalyst layer sheet resistance

Abstract

Large-scale deployment of polymer electrolyte membrane water electrolysis, which is a promising technology for green hydrogen production, requires significant reduction of Ir in catalyst layer due to its high material cost. However, as the Ir amount in the catalyst layer decreases, number of electrically-isolated-inactive catalysts increases, resulting in poor performance. Here we show that the nanostructured textiles essentially avoids the formation of such inactive catalysts, enables unprecedented long-term hydrogen evolution with ultralow Ir mass loadings at high rates. We reveal that achieved high performance is derived from the low resistivity of prepared nanostructured textile which have a unique porous, three-dimensional structure. We also show that the nanostructured textiles facilitate simple catalyst-coated membrane production, which does not require liquid-phase processes or produce chemical waste. The method we developed can also be applied to a variety of zero-gap electrochemical conversion cells that require a high-rate catalytic reactions with small amounts of catalyst.