Nd6Ir2O13 as an Efficient Electrocatalyst Boosts the Oxygen Evolution Reaction in Acidic Media

A highly active and robust electrocatalyst for the oxygen evolution reaction (OER) in acidic conditions is essential for proton-exchange membrane water electrolyzers. Herein, a novel Nd6Ir2O13 electrocatalyst was synthesized and first applied in acidic OER. During the OER, surface Nd atoms are leached out to form active hydrated IrOx; meanwhile, the coordination environment of Ir remains relatively stable. Benefiting from the low Ir content (26.4 wt %), Nd6Ir2O13 affords an Ir mass activity of 123.5 mA per mgIr at an overpotential of 300 mV, about 42-fold that of IrO2. Notably, Nd6Ir2O13 needs an ultralow overpotential of 291 mV to acquire a current density of 10 mA cm–2 and continuously catalyzes OER for 70,000 s with little overpotential increase, far beyond that of the benchmark IrO2 and most of the electrocatalysts for the acidic OER. This work opens a new type of Ir-based oxides with ultralow Ir content, which expands the acidic OER electrocatalyst family of multimetal oxides.