Facile synthesis of SrIrO₃ by mechanical activation assisted solid-state reaction for efficient oxygen evolution reaction in acidic media

Oxygen evolution reaction (OER) is an anodic reaction for copper electrowinning that occurs during the hydrometallurgical manufacturing process of copper, and the development of a highly active catalyst for the OER in an acidic electrolyte is of vital importance in terms of energy saving. Herein, we report a facile method to synthesize the SrIrO₃ catalyst by solid-state reaction method assisted by mechanical activation. The results demonstrated that mechanical activation is critical to the successful fabrication of the SrIrO₃ catalyst. XRD and TEM results confirmed the formation of SrIrO₃ without other impurities, and XPS results revealed that some of the Ir species, including Ir⁴⁺, existed in +3 valence states. The catalyst shows both high catalytic activity for OER and stability in a sulfuric acid solution, with a Tafel slope of 48 mV dec⁻¹ and almost no current decay after 1000 voltammetry cycles. This investigation is of fundamental and practical importance for synthesizing highly efficient SrIrO₃ OER electro-catalysts to be potentially applied in copper electrowinning. (paper)