IrCo nanocacti on CoxSy nanocages as a highly efficient and robust electrocatalyst for the oxygen evolution reaction in acidic media

Abstract

Developing highly efficient Ir-based electrocatalysts for the oxygen evolution reaction (OER) has been an important agenda in spearheading the water splitting technology. In this study, the synthesis of IrCo nanocacti on Co_xS_y nanocages (ICS NCs) is demonstrated by utilizing CoO@Co_xS_y nanoparticles as reactive nanotemplates. In addition to the high catalytic activities with a low overpotential of 281 mV at 10 mA cm⁻² and an outstanding mass activity of 1285 mA mg_Ir⁻¹ at 1.53 V, the ICS NCs endure a prolonged OER test for over 100 h, greatly outperforming other previously reported Ir-based electrocatalysts. This work suggests that the unique hetero-nanostructure of IrCo/Co_xS_y induces in situ S doping during electrochemical oxidation and the beneficial effect of S doping on the enhanced stability of ICS NCs for the OER.