Preparation of Solid Solution and Layered IrO x-Ni(OH)2Oxygen Evolution Catalysts: Toward Optimizing Iridium Efficiency for OER

Jonathan Ruiz Esquius, Gerardo Algara-Siller, Ioannis Spanos, Simon J. Freakley, Robert Schlögl, Graham J. Hutchings

Research output: Contribution to journalArticlepeer-review


Minimizing iridium loading in oxygen evolution reaction (OER) catalysts, without impairing electrocatalytic activity and stability is crucial to reduce the cost of water electrolysis. In this work, two Ir0.5Ni0.5Ox mixed oxide catalysts with layered and solid solution morphologies were prepared by modifying a facile hydrothermal methodology. The catalytic OER activity and stability of the Ir-Ni catalyst with a homogeneous distribution (IrNi-HD) was seriously compromised compared to pure IrOx due to the high concentration of surface nickel prone to corrosion under reaction conditions. However, the design of layered IrOx-Ni(OH)x (IrNi-LY) with Ir at the exposed surface allowed a 50% reduction in the molar concentration of the precious metal on the electrode compared to IrOx without impairing the catalytic activity or stability. As a result, IrNi-LY outperformed IrOx in activity when normalized to the Ir mass.

Original languageEnglish
Pages (from-to)14640-14648
Number of pages9
JournalACS Catalysis
Issue number24
Early online date26 Nov 2020
Publication statusPublished - 18 Dec 2020


  • amorphous iridium oxo-hydroxide
  • electrocatalysis
  • hydrothermal synthesis
  • iridium nickel mixed oxide
  • iridium oxide
  • oxygen evolution reaction

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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