Reconstructing a stable surface on pyrite-type iridium telluride to promote the oxygen evolution reaction in acid

Surface reconstruction is inevitable for oxygen evolution reaction (OER) electrocatalysts. Here, we report that pyrite-type iridium telluride (Ir₃Te₈) can undergo favorable surface reconstruction during the OER process in acid. Compared with a IrTe₂ counterpart, the relatively weak Ir–Te bonds in Ir₃Te₈ facilitate the formation of a Ir₃Te₈/IrO₂-TeO₂ heterojunction. Strengthened orbital interaction between the reconstructed IrO₂-TeO₂ layer and Ir₃Te₈ optimizes the electronic structure to enhance the electrocatalytic activity. As a result, the reconstructed Ir₃Te₈ with a stable surface achieves a low overpotential of 467.8 mV at a current density of 1 A cm⁻² and maintains stability over 1,000 h at 10 mA cm⁻². Although surface reconstruction is inevitable, this work demonstrates that its positive impacts can be maximized through optimization of the structural characteristics of the initial iridium telluride polymorphs to customize the reconstruction process. This highlights a design strategy for advanced OER catalysts that operate in acidic environments, including Ir-based catalysts and beyond.