High Loading of Iridium Single Atoms in NiCo2O4 for Enhanced Acidic Oxygen Evolution Reaction

Abstract

The development of high loading single-atom electrocatalysts presents significant potential for enhancing the performance of acidic oxygen evolution reaction (OER). Herein, a high loading (7.98 wt%) iridium single atom doped NiCo2O4 (IrH-NiCo2O4) catalyst was prepared by using an ion-exchange pyrolysis method. The optimized IrH-NiCo2O4 demonstrated an enhanced OER performance, achieving an overpotential of 240 mV at a current density of 10 mA·cm−2, along with exceptional stability over 282 hours in 0.5 M H2SO4 solution. Additionally, it demonstrated an overall mass activity of 377.05 mA mgIr -1 at a 300 mV OER overpotential, surpassing the performance of commercial IrO2. Density functional theory calculations revealed that the high-density of Ir-single atom doping enhances the adsorption energy of oxygen-containing intermediates, thereby promoting the OER process. This study work offers a viable strategy for fabricating high-loading single-atom catalysts, offering insights that can be generalized to other systems and paving the way for advancing their industrial-scale applications.