Self-supported amorphous iridium oxide catalysts for highly efficient and durable oxygen evolution reaction in acidic media. (20th September 2021)

• Record Type: Journal Article
• Authors: Zhao, Rong; Wang, Zheyuan; Xu, Qingli; Niu, Xiaopo; Han, Yunxi; Qin, Yue; Wang, Qingfa
• Is Part Of: Electrochimica acta. Volume 391(2021)
• Publication Date: 2021-09-20
• Subjects: Amorphous IrOx -- OER -- Electrodeposition -- Self-supported -- Long-term durability; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2021.138955
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: A novel electrodeposition method is developed to prepare self-supported amorphous IrOx /Ti electrode. Pre-activation plays a significant role in in-situ constructing an amorphous film. The amorphous IrOx film exposes high contents of active Ir III species and surface hydroxides to enhance the OER performance. Amorphous-crystalline synergy and rich interface contribute to the superior stability and activity. A super durability for 190 h at 10 mA cm −2 and 50 mA cm −2 was achieved for amorphous IrOx -50/Ti. Abstract: Developing highly active and stable electrocatalysts for acidic oxygen evolution reaction is still a great challenge. Herein, we developed a novel self-supported amorphous IrOx catalyst (IrOx /Ti) encapsulated with a small number of crystalline nanoparticles for efficient acidic OER. The resulting IrOx -50-AC/Ti electrode exhibits a superior OER performance with an overpotential of 250 mV at 10 mA cm −2 and Tafel slope of 50.4 mV dec −1 in 0.1 M HClO4 . High contents of Ir III species and surface hydroxide groups, hierarchically porous structure and high defective density contribute to boost the OER activity. Importantly, the amorphous IrOx -50-AC/Ti also demonstrates a super long-term durability for 190 h due to the strong interaction between IrOx film and Ti. The unique amorphous-crystalline structure also enhances the stability and the activity by promoting the synergy between amorphous phase and crystalline phase. This work provides some valuable insights on developing efficient Ir-based catalysts for acidic water splitting. Graphical abstract: Image, graphical abstract A novel self-supported amorphous IrOx catalyst (IrOx /Ti) is developed by an electrodeposition strategy for efficient acidic OER. The optimized amorphous IrOx -50-AC/Ti demonstrates a super long-term durability for 190 h and an excellent activity with an overpotential of 250 mV to obtain 10 mA cm −2 in 0.1 M HClO4 .