Dy2NiRuO6 perovskite with high activity and durability for the oxygen evolution reaction in acidic electrolyte

Abstract

Ru mixed oxides may be suitable materials to replace state-of-the-art Ir-based catalysts in the anode of proton exchange membrane electrolyzers. To do this, the activity and especially the durability of Ru for the oxygen evolution reaction (OER) in acidic electrolyte should be improved. This work reports a family of Ru-based perovskites that combines both high activity and durability for the OER in acidic electrolyte. R₂NiRuO₆ double perovskites with R³⁺ = Pr³⁺, Nd³⁺, Tb³⁺, Dy³⁺, Y³⁺, Ho³⁺ and Er³⁺, and with Ni²⁺ and Ru⁴⁺ occupying B and B′ positions have been synthesized and evaluated for the OER in acidic electrolyte. The OER activities of R₂NiRuO₆ mixed oxides depend on the nature of R³⁺, with Dy₂NiRuO₆ displaying the highest activity (1.507 V at 10 mA cm⁻²) and being stable for more than 400 consecutive OER cycles measured at a slow scan rate. Characterization data indicate that the shorter Ru–O bonds in Dy₂NiRuO₆ are beneficial for the OER performance compared to the rest of the series. Computational modelling shows that Ru sites at pristine Dy₂NiRuO₆ are highly active for the OER, and their activity increases slightly upon Dy dissolution and progressively decreases as the local ratio of Ni to Ru is lowered.