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  • Better Durability with Less Iridium: Control of the Crystal Phase of Iridium–Ruthenium–Manganese Electrocatalysts for Oxygen Evolution Reaction Performance

This content will become publicly available on November 6, 2026

Title: Better Durability with Less Iridium: Control of the Crystal Phase of Iridium–Ruthenium–Manganese Electrocatalysts for Oxygen Evolution Reaction Performance
This paper presents a study of designing phase-specific and -mixed Ir−Ru−Mn trimetallic electrocatalysts with enhanced performance. By changing the content of Ru, the alloy electrocatalyst evolved from a face-centered tetragonal (fct) phase to a mixture of fct and hexagonal close-packed (hcp) phases and finally to the hcp phase. Among these trimetallic systems, the hcp-phase Ir0.23Ru0.20Mn0.57 electrocatalyst (Ru/Ir = 0.47:0.53) delivered the best performance toward the oxygen evolution reaction (OER), achieving an overpotential of 226 mV at 10 mA cm−2 and a Tafel slope of ∼46.8 mV dec−1. Interestingly, this low-Ir hcp-phase catalyst maintained stable operation for >57 h at a current density of 100 mA cm−2 in 0.1 M HClO4, whereas the Ir-rich fct-phase counterpart (Ir0.35Ru0.07Mn0.58) degraded within 22 h under identical conditions. Potentiodynamic polarization curve study indicated that oxidative dissolution is the dominant degradation pathway, and the structural characterizations indicated that the hcp-phase alloy remained intact, while rutile-type IrRuMnOx oxide was formed for the fct-phase alloy electrocatalyst. These results underscore the effect of the crystal phase on OER durability of the electrocatalyst and point to a design strategy for improving the durability of OER electrocatalysts without increasing the Ir content.  more » « less
Award ID(s):
2055734
PAR ID:
10646577
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
American Chemical Society
Date Published:
Journal Name:
Chemistry of Materials
ISSN:
0897-4756
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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