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Abstract Developing highly active, durable, and cost‐effective electrocatalysts for the oxygen evolution reaction (OER) is of prime importance in proton exchange membrane (PEM) water electrolysis techniques. Herein, a surface lanthanum‐deficient (SLD) iridium oxide as a highly efficient OER electrocatalyst is reported (labeled as La 3 IrO 7 ‐SLD), which is obtained by electrochemical activation, and shows better activity and durability than that of commerically available IrO 2 as well as most of the reported Ir‐based OER electrocatalysts. At a current density of 10 mA cm −2 , the overpotential of La 3 IrO 7 ‐SLD is 296 mV, which is lower than that of IrO 2 (316 mV). Impressively, the increase of potential is less than 50 mV at a voltage–time chronopotentiometry extending for 60 000 s using a glass carbon electrode that is vastly superior to IrO 2 . Moreover, the mass activity of the catalyst is approximately five times higher than that of IrO 2 at 1.60 V versus reversible hydrogen electrode. Density functional theory calculations suggest that a lattice oxygen participating mechanism with central Ir atoms serving as active sites (LOM‐Ir) rationalizes the high activity and durability for the La 3 IrO 7 ‐SLD electrocatalyst. The favorable energy level of surface active Ir 5d orbitals relative to coordinated O 2p orbitals makes the La 3 IrO 7 ‐SLD more active.
Qin et al. (Mon,) studied this question.