Dimensionally Stable Ru/Ir/TiO2-Anodes with Tailored Mesoporosity for Efficient Electrochemical Chlorine Evolution

Chlorine evolution is one of the most important electrochemical reactions applied in industry. We present a method for the synthesis of chlorine evolution catalysts with improved performance. The performance increase results from the introduction of controlled mesoporosity into the pore system of Ru- and Ir-containing TiO2 catalysts by pore templating with micelles of amphiphilic block-copolymers. Micelle-templated TiO2-based catalysts were synthesized with loadings up to 15 wt % of either Ru, Ir, or a combination of both active metals. The catalysts’ walls are composed of nanocrystalline mixed oxides with rutile structure. The templated mesopores are about 10 nm in size and form an ordered cubic pore system with good pore connectivity. All studied catalysts are active in chlorine evolution. Adding templated mesoporosity doubles the catalyst performance at identical catalyst composition. The influences of film thickness, composition, and porosity of the developed catalytic coatings on the catalytic performance are discussed.