Hexavalent iridium boosts oxygen evolution performance

Proton exchange membrane water electrolysis (PEMWE) involves the oxygen evolution reaction (OER) at the anode to produce O2 and the hydrogen evolution reaction (HER) at the cathode to produce H2. Although hydrogen is the desired product of PEMWE, the main challenge lies on the anode side, as the OER is kinetically more sluggish and thus requires a more efficient catalyst and higher overpotential (>1.3 V vs. reversible hydrogen electrode, RHE) than the HER (>0 V vs. RHE). Recently, Nakamura et al. developed a new atomically dispersed hexavalent iridium oxide catalyst (IrVI-ado) with a much lower Ir loading and higher specific activity than traditional IrO2. This breakthrough offers hope for advancing PEMWE technology.