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, Irlat@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.