(A) study on iridium nanosheet catalysts supported on titanium oxide for oxygen evolution reaction

Abstract

Polymer electrolyte membrane water electrolyte(PEMWE) is a technology that can convert electricity into green hydrogen, which is one of the key elements for operating a hydrogen society. Development of highly active and durable catalysts to reduce usage of iridium for oxygen evolution reaction(OER) is essential for cost-effective hydrogen production. In this work, we present an approach to iridium nanosheet(NS) catalysts supported on titanium oxide(TiO2). Ir NSs were synthesized by a facile method by directly annealing a mixture of Ir precursor and alkali salt, and then TiO2 was introduced to maximize an active area of the Ir NS/TiO2 catalyst. In the process of optimizing the catalysts, we revealed that the weight percentage (wt.%) of Ir is a crucial factor in determining the electrical conductivity and ECSA of Ir NS/TiO2 catalysts, which affects OER activities. We revealed that Ir NS/TiO2 catalysts have higher electrical conductivity than Ir NP/TiO2 and wider ECSA than Ir black and Ir NP/TiO2 catalysts. In particular, Ir NS/TiO2_40 wt.% catalysts exhibited superior OER activity and durability than Ir black and Ir NP/TiO2 with same Ir wt.%.