Comparative Analysis of Synthesis Routes for Antimony-Doped Tin Oxide-Supported Iridium and Iridium oxide Catalysts for OER in PEM Water Electrolysis

Kurzfassung

This study investigates and compares four different deposition methods for an iridium-based catalyst on antimony-doped tin oxide support for oxygen evolution reaction in water electrolysis. Different synthesis routes often lead to varying properties of the resulting catalyst and can result in performance disparities. Here, some of the most prominent methods are carried out on the same support material and evaluated with special focus on the deposition yield of Ir and thus cost efficiency along with electrochemical performance. The catalysts are also assessed based on their chemical composition, namely Ir or IrO2-based, with an additional thermal treatment to convert Ir to IrO2 species. The chosen synthesis routes result in different Ir species to obtain tetragonal IrO2 a modified Adams fusion approach delivers the best controllable and highest Ir loading and thus superior electrochemical performance. As far as metallic Ir catalysts are concerned, a wet-chemical reduction-based synthesis results in the most desirable catalyst, which however falls behind the Adams fusion catalyst upon thermal treatment to IrO2. The work in this study is a comprehensive analysis of different synthesis influences and recommends practices for laboratory-based syntheses and an outlook on industrial viability.