Dy2NiRu0.5Ir0.5O6: A Catalyst Precursor for Acidic Oxygen Evolution Reaction

This article presents the synthesis and evaluation of a novel double perovskite Dy₂NiRu_0.5Ir_0.5O₆, as a promising catalyst precursor for the oxygen evolution reaction (OER) in acidic electrolyte. In this perovskite, which was synthesised by a simple sol-gel process, there are two different B sites, one with Ni²⁺ atoms, and the other in which half of the Ir⁴⁺ atoms are replaced by Ru⁴⁺.Electrochemical measurements revealed and exceptional OER activity, with an Ir-normalised mass activity 5–7 times higher than the state-of-the-art IrO₂ benchmarks. The catalyst also exhibited remarkable stability, maintaining a stable performance for at least 36,000 OER cycles. Structural and compositional analyses during cycling revealed a transformation of the pristine double perovskite structure into a 3D-hollow Ir_0.9Ru_0.1O_x framework. The reconstruction, which is driven by the dissolution of Dy³⁺, Ni²⁺ and part of Ru⁴⁺, results in a highly active and durable electrocatalyst. The enhanced OER performance is attributed to the composition and increased surface area of the reconstructed Ir_0.9Ru_0.1O_x hollow structure.