Stabilizing iridium sites via interface and reconstruction regulations for water oxidation in alkaline and acidic media

Abstract

Exploring effective iridium (Ir)-based electrocatalysts with stable iridium centers is highly desirable for oxygen evolution reaction (OER). Herein, we regulated the incorporation manner of Ir in Co₃O₄ support to stabilize the Ir sites for effective OER. When anchored on the surface of Co₃O₄ in the form of Ir(OH)₆ species, the created Ir-OH-Co interface leads to a limited stability and poor acidic OER due to Ir leaching. When doped into Co₃O₄ lattice, the analyses of X-ray absorption spectroscopy, in-situ Raman, and OER measurements show that the partially replacement of Co in Co₃O₄ by Ir atoms inclines to cause strong electronic effect and activate lattice oxygen in the presence of Ir-O-Co interface, and simultaneously master the reconstruction effect to mitigate Ir dissolution, realizing the improved OER activity and stability in alkaline and acidic environments. As a result, Ir_lat@Co₃O₄ with Ir loading of 3.67 wt% requires 294 ± 4 mV / 285 ± 3 mV and 326 ± 2 mV to deliver 10 mA cm⁻² in alkaline (0.1 M KOH / 1.0 M KOH) and acidic (0.5 M H₂SO₄) solution, respectively, with good stability.