IrRe-IrOx electrocatalysts derived from electrochemically oxidized IrRe thin films for efficient acidic oxygen evolution reaction

Slow kinetics of oxygen evolution reaction (OER), combined with harsh conditions of acidic media, significantly limits the progress of large-scale hydrogen production by water splitting. Efficient, stable and less-expensive catalysts are required to overcome such restrictions. Herein, we report preparation of IrRe-IrOx based catalysts with record high mass activity. The electrocatalyst was prepared by magnetron sputtering deposition of metallic Ir-Re thin film with subsequent electrooxidation. The optimal composition of as-deposited Ir-Re catalyst was defined as Ir39Re61. During electrooxidation process Re atoms are dissolved promoting metallic Ir oxidation to highly active amorphous IrOx phase with high surface area. The IrRe-IrOx catalyst exhibits low OER overpotential of 248 mV at 10 mA•cm-2 current density and mass activity of 4400 mA•mg−1. High mass OER activity of the IrRe-IrOx catalyst is result of combination of high surface area, low catalyst loading and presence of amorphous IrOx on catalyst surface.