Titanium oxynitride, a derivative of titanium nitride via controlled oxidation, is reported as a functional matrix for anchoring iridium (Ir) active species as an efficient OER electrocatalyst. Notably, with a low Ir loading of merely 33 wt.%, the catalyst exhibits robust catalytic performance in an acidic electrolyte.

Abstract

Iridium-based materials are state-of-the-art electrocatalysts for the acidic oxygen evolution reaction (OER). In this work, an efficient low-iridium electrocatalyst is successfully anchored on a typical titanium oxynitride support, achieving an overpotential as low as 278 mV and robust stability over 1000 h at 10 mA cm⁻² in 0.5 M H₂SO₄. It is discovered that high valence Ir(VI) sites can be in situ formed under the interaction of support during OER procedure, accounting for the superior performance. We show that rational design of support can realize activity and stability enhancement, demonstrating a feasible approach for acidic OER electrocatalysts.