RT Journal Article T1 How oxidation state and lattice distortion influence the oxygen evolution activity in acid of iridium double perovskites A1 Retuerto, Maria A1 Pascual, Laura A1 Pique, Oriol A1 Kayser González, Paula A1 Abdel Salam, Mohamed A1 Mokhtar, Mohamed A1 Alonso, Jose Antonio A1 Peña, Miguel A1 Calle-Vallejo, Federico A1 Rojas, Sergio AB In view of iridium's scarceness and high cost, Ir-containing catalysts for water electrolyzers should have low loadings and maximal utilization. Here, we studied low-Ir-content, highly active, double perovskites (Sr2MIrO6, M = Ni, Co, Sc and Fe) for the oxygen evolution reaction (OER) in acid combining electrochemical experiments, DFT, and advanced characterization techniques. The initial OER performance depends on Ir's oxidation state and the geometric features of IrO6 frameworks, which are tuned by the choice of M. Higher oxidation states, particularly Ir6+, enhance the OER activity: Sr2NiIrO6 and Sr2CoIrO6 display potentials of ∼1.53 V at 10 mA cm−2, comparable to the best Ir-based catalysts in the literature. However, because of their less symmetric structures, perovskites with Ir6+ are less stable, prone to surface reconstruction and their cations leach under OER conditions. These results show that improved iridium-based OER electrocatalysts in acid can be designed by balancing their activity and stability. PB Royal Society of Chemistry SN 2050-7488 YR 2021 FD 2021 LK https://hdl.handle.net/20.500.14352/92542 UL https://hdl.handle.net/20.500.14352/92542 LA eng NO Retuerto, María, et al. «How Oxidation State and Lattice Distortion Influence the Oxygen Evolution Activity in Acid of Iridium Double Perovskites». Journal of Materials Chemistry A, vol. 9, n.o 5, 2021, pp. 2980-90. https://doi.org/10.1039/D0TA10316K. NO Ministerio de Economía y Competitividad (España) NO Ministerio de Ciencia, Investigación y Universidades (España) NO Generalitat de Catalunya DS Docta Complutense RD 7 abr 2025