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

Abstract

The poor catalyst stability, stemming from serious cation dissolution and uncontrollable amorphization, remains an outstanding problem in the acidic oxygen evolution reaction (OER). Herein, we report the synthesis and characterization of honeycomb layered strontium iridate (SrIr2O6) and demonstrate its potential as an efficient OER electrocatalyst with robust structural stability in acid. In contrast to the vast majority of iridate catalysts, SrIr2O6 can keep both bulk and surface structures crystalline during OER, as opposed to forming an amorphous active phase. The edges of SrIr2O6 are highly catalytically active for OER by following the adsorbate evolution mechanism, but the basal planes are catalytically inert. SrIr2O6 exhibits ∼10-fold higher intrinsic activity than the benchmark catalyst IrO2, affords an extremely low total iridium leaching level (∼0.03%) during OER, and retains its catalytic activity for more than 300 h.