Self-supported amorphous iridium oxide catalysts for highly efficient and durable oxygen evolution reaction in acidic media

Developing highly active and stable electrocatalysts for acidic oxygen evolution reaction is still a great challenge. Herein, we developed a novel self-supported amorphous IrO x catalyst (IrO x /Ti) encapsulated with a small number of crystalline nanoparticles for efficient acidic OER. The resulting IrO x -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 HClO 4 . 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 IrO x -50-AC/Ti also demonstrates a super long-term durability for 190 h due to the strong interaction between IrO x 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.