Structurally Robust Honeycomb Layered Strontium Iridate as an Oxygen Evolution Electrocatalyst in Acid

The poor catalyst stability, stemming from serious cationdissolutionand uncontrollable amorphization, remains an outstanding problem inthe acidic oxygen evolution reaction (OER). Herein, we report thesynthesis and characterization of honeycomb layered strontium iridate(SrIr2O6) and demonstrate its potential as anefficient OER electrocatalyst with robust structural stability inacid. In contrast to the vast majority of iridate catalysts, SrIr2O6 can keep both bulk and surface structures crystallineduring OER, as opposed to forming an amorphous active phase. The edgesof SrIr2O6 are highly catalytically active forOER by following the adsorbate evolution mechanism, but the basalplanes are catalytically inert. SrIr2O6 exhibits similar to 10-fold higher intrinsic activity than the benchmark catalystIrO(2), affords an extremely low total iridium leaching level(similar to 0.03%) during OER, and retains its catalytic activity formore than 300 h.

Automated summary

We report the synthesis and characterization of honeycomb layered strontium iridate (SrIr2O6) as an efficient electrocatalyst for the acidic oxygen evolution reaction (OER) with robust structural stability. Unlike most iridate catalysts, SrIr2O6 can maintain its crystalline structure during OER instead of forming an amorphous active phase. The edges of SrIr2O6 demonstrate high catalytic activity for OER following the adsorbate evolution mechanism, while the basal planes are catalytically inert. SrIr2O6 exhibits about 10-fold higher intrinsic activity than the benchmark catalyst IrO(2), with minimal iridium leaching (approximately 0.03%) and long-term catalytic stability for over 300 hours.