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A major challenge with water splitting technology is to develop highly active and stable electrocatalysts for the oxygen evolution reaction (OER). IrO2 – based electrocatalysts are one of the most active electrocatalysts for proton exchange membrane (PEM) electrolysers, due to their excellent activity for the OER in acidic conditions. However, IrO2 often suffers from dissolution during electrolysis due to phase transitions into more soluble forms. Herein, a range of electrodeposited IrO2 films annealed to different temperatures of up to 500°C are prepared to understand the influence that crystalline/amorphous interfaces have on performance during accelerated degradation tests in concentrated acidic solutions. This study showed that an IrO2 film annealed at 300 °C exhibited the highest catalytic activity with a low overpotential of 150 mV at 10 mA cm−2, the smallest Tafel slope of 51 mV dec−1, with a less progressive decay in activity over a period of 8 h of accelerated degradation testing. This contrasts with both fully amorphous or more crystalline IrO2 films that decayed much more rapidly within 1 h of testing indicating the role that amorphous/crystalline regions have on OER performance. [ABSTRACT FROM AUTHOR]

Invited for this issue's Front Cover is the group of Prof. Anthony O'Mullane from the School of Chemistry and Physics, Queensland University of Technology (QUT). The cover picture shows the presence of crystalline and amorphous domains in an electrodeposited IrO2 film which demonstrate different activity for the oxygen evolution reaction. The presence of amorphous/crystalline interfaces was found to improve the stability of the electrocatalyst. Cover design by Thi Hong Nga Ngo. Read the full text of the Research Article at 10.1002/celc.202300438. [ABSTRACT FROM AUTHOR]

Keywords: Iridium oxide; oxygen evolution reaction; electrodeposition; surface area; annealingThe Front Cover shows the presence of crystalline and amorphous domains in an electrodeposited IrO2 film which demonstrate different activity for the oxygen evolution reaction. The presence of amorphous/crystalline interfaces was found to improve the stability of the electrocatalyst. Cover design by Thi Hong Nga Ngo. More information can be found in the Research Article by T. H. Nga Ngo et al...By Thi Hong Nga Ngo; Jonathan Love and Anthony P. O'MullaneReported by Author; Author; Author [Extracted from the article]