Ultrathin Iridium Carbonyl Formate for Efficient and Durable Acidic Oxygen Evolution Electrocatalysis

Proton exchange membrane water electrolyzers (PEMWEs) currently rely on benchmark iridium (Ir)-based electrocatalysts for the acidic oxygen evolution reaction (OER) at the anode. Herein, we report a novel two-dimensional (2D) complex-based electrocatalyst of Ir carbonyl formate (IrCF) with an atomic-level thickness architecture, synthesized using a fast microwave method, for a highly active and stable OER in an acidic solution. The local atomic coordination configuration of Ir active sites can be further finely regulated through the introduction of 1,3,5-benzenetricarboxylic molecules to enhance OER performance. An optimized overpotential as low as 248 mV can be achieved at a current density of 10 mA cm-2 in 0.1 M HClO4 solution, with accelerated kinetics showing a Tafel slope of 32 mV dec-1. 2D IrCF could work stably at a current density of 1 A cm-2 in a PEMWE device for more than 100 hours without obvious degradation. Iridium carbonyl formate nanoflakes were fabricated swiftly via a liquid-phase microwave method, showcasing a remarkable acidic water oxidation performance and sustaining operation in proton exchange membrane electrolysis at 1.0 A cm-2 for 100 h.