High‐Performance Low‐Iridium Catalyst for Water Oxidation: Breaking Long‐Ranged Order of IrO2 by Neodymium Doping

Abstract

AbstractExploring efficacious low‐Ir electrocatalysts for oxygen evolution reaction (OER) is crucial for large‐scale application of proton exchange membrane water electrolysis (PEMWE). Herein, an efficient non‐precious lanthanide‐metal‐doped IrO2 electrocatalyst is presented for OER catalysis by doping large‐ionic‐radius Nd into IrO2 crystal. The doped Nd breaks the long‐ranged order structure by triggering the strain effect and thus inducing an atomic rearrangement of Nd─IrO2 involving the forming of Nd─O─Ir bonds along with an increased amount of oxygen vacancies (Ov), giving rise of a long‐ranged disorder but a short‐ranged order structure. The formed Nd─O─Ir bonds tailor the electronic structure of Ir, leading to a lowered d‐band center that weakens intermediates absorption on Ir sites. Moreover, doping Nd triggers Nd─IrO2 to catalyze OER mainly through lattice oxygen mechanism (LOM) by activating lattice oxygen owing to abundant Ov. The optimal catalyst only requires a relatively low overpotential of 263 mV@10 mA cm−2 with a high mass activity of 216.98 A gIr−1 (at 1.53 V) (eightfold of commercial IrO2), and also shows a superior durability at 50 mA cm−2 (20 h) than commercial IrO2 (3 h) due to the oxidation‐suppressing effect induced by Nd doping. This work offers insights into designing high‐performance low‐Ir electrocatalysts for PEMWE application.