Iridium metallene oxide for acidic oxygen evolution catalysis

Exploring new materials is essential in the field of material science. Especially, searching for optimal materials with utmost atomic utilization, ideal activities and desirable stability for catalytic applications requires smart design of materials' structures. Herein, we report iridium metallene oxide: 1 T phase-iridium dioxide (IrO2) by a synthetic strategy combining mechanochemistry and thermal treatment in a strong alkaline medium. This material demonstrates high activity for oxygen evolution reaction with a low overpotential of 197 millivolt in acidic electrolyte at 10 milliamperes per geometric square centimeter (mA cm(geo)(-2)). Together, it achieves high turnover frequencies of 4.2 s(UPD)(-1) (3.0 s(BET)(-1)) at 1.50 V vs. reversible hydrogen electrode. Furthermore, 1T-IrO2 also shows little degradation after 126 hours chronopotentiometry measurement under the high current density of 250 mA cm(geo)(-2) in proton exchange membrane device. Theoretical calculations reveal that the active site of Ir in 1T-IrO2 provides an optimal free energy uphill in *OH formation, leading to the enhanced performance. The discovery of this 1T-metallene oxide material will provide new opportunities for catalysis and other applications. Identifying new, active material phases provides a promising avenue in the development of efficient catalysts. Here, authors demonstrate a metastable 1T-phase IrO2 metallene oxide as an oxygen evolution electrocatalyst in acidic electrolytes.

Automated summary

Exploring new materials with optimal atomic utilization, activity, and stability for catalytic applications is crucial in material science. In this study, the iridium metallene oxide 1T-phase IrO2 was synthesized through a combination of mechanochemistry and thermal treatment, showing high activity and stability for the oxygen evolution reaction in acidic electrolytes. This discovery provides new opportunities for catalysis and other applications by identifying new, active material phases for efficient catalyst development.