Iridium Doped Pyrochlore Ruthenates for Efficient and Durable Electrocatalytic Oxygen Evolution in Acidic Media. Issue 30 (3rd July 2022)

• Record Type: Journal Article
• Authors: Liu, Hai; Zhang, Zhuang; Li, Mengxuan; Wang, Zhaolei; Zhang, Xingheng; Li, Tianshui; Li, Yaping; Tian, Shubo; Kuang, Yun; Sun, Xiaoming
• Is Part Of: Small. Volume 18:Issue 30(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-03
• Subjects: hydrogen production -- oxygen evolution reaction -- proton exchange membranes -- pyrochlore ruthenates -- stability; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202202513
• Languages: English
• ISSNs: 1613-6810

Abstract

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. Ru‐based catalysts have high activities but always suffer from severe fading and dissolution issues, which cannot satisfy the stability demand of PEM. Herein, a series of iridium‐doped yttrium ruthenates pyrochlore catalysts is developed, which exhibit better activity and much higher durability than commercial RuO2, IrO2, and most of the reported Ru or Ir‐based OER electrocatalysts. Typically, the representative Y2 Ru1.2 Ir0.8 O7 OER catalyst demands a low overpotential of 220 mV to achieve 10 mA cm −2, which is much lower than that of RuO2 (300 mV) and IrO2 (350 mV). In addition, the catalyst does not show obvious performance decay or structural degradation over a 2000 h stability test. EXAFS and XPS co‐prove the reduced valence state of ruthenium and iridium in pyrochlore contributes to the improved activity and stability. Density functional theory reveals that the potential‐determining steps barrier of OOH* formation is greatly depressed through the synergy effect of Ir and Ru sites by balancing the d band center and oxygen intermediates binding ability. Abstract : The fading issues for Ru‐based oxygen evolution reaction catalysts are addressed by changing the coordination environment of RuO6 through Ir doping and strengthening the interaction between RuO6 and IrO6 with Y linkage, triggering low overpotential of 220 mV and more than 2000 h stability, especially stability under high current density.