Atomically dispersed hexavalent iridium oxide from MnO2 reduction for oxygen evolution catalysis

• 成果类型: Article
• 署名作者: Li, Ailong; Kong, Shuang; Adachi, Kiyohiro; Ooka, Hideshi; Fushimi, Kazuna; Jiang, Qike; Ofuchi, Hironori; Hamamoto, Satoru; Oura, Masaki; Higashi, Kotaro; Kaneko, Takuma; Uruga, Tomoya; Kawamura, Naomi; Hashizume, Daisuke; Nakamura, Ryuhei
• 署名单位: RIKEN; RIKEN; Westlake University; Chinese Academy of Sciences; Dalian Institute of Chemical Physics, CAS; Japan Synchrotron Radiation Research Institute; RIKEN; University of Electro-Communications - Japan; Institute of Science Tokyo; Tokyo Institute of Technology
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8766
• DOI: 10.1126/science.adg5193
• 发表日期: 2024-05-10
• 页码: 666-670
• 关键词: membrane-electrode assemblies; cs-substituted phosphotungstates; ray-absorption spectroscopy; pem water electrolyzers; high-surface-area; magnetic-properties; high-performance; doped tio2; electrochemical characterization; reaction electrocatalysts

摘要

Hexavalent iridium (Ir-VI) oxide is predicted to be more active and stable than any other iridium oxide for the oxygen evolution reaction in acid; however, its experimental realization remains challenging. In this work, we report the synthesis, characterization, and application of atomically dispersed IrVI oxide (Ir-VI-ado) for proton exchange membrane (PEM) water electrolysis. The Ir-VI-ado was synthesized by oxidatively substituting the ligands of potassium hexachloroiridate(IV) (K2IrCl6) with manganese oxide (MnO2). The mass-specific activity (1.7 x 10(5) amperes per gram of iridium) and turnover number (1.5 x 10(8)) exceeded those of benchmark iridium oxides, and in situ x-ray analysis during PEM operations manifested the durability of Ir-VI at current densities up to 2.3 amperes per square centimeter. The high activity and stability of Ir-VI-ado showcase its promise as an anode material for PEM electrolysis.