Electronic modulation of Ir active centers by Co3O4 support enables high‑performance acidic oxygen evolution reaction

Modulating the electronic structure of active sites via support engineering remains the premier method for improving acidic oxygen evolution reaction (OER) kinetics over Ir-based systems while minimizing precious metal consumption. Here, we prepared IrO x /Co 3 O 4 by loading IrO x nanoparticles onto spherical Co 3 O 4 supports, achieving an efficient acidic OER catalyst. The Co 3 O 4 support significantly boosts the electrocatalytic performance of IrO x /Co 3 O 4 by modulating the electronic configuration of Ir active sites via Ir–O–Co coordination. Such interaction optimizes the *OOH adsorption energy during OER, thereby delivering markedly enhanced catalytic activity. The IrO x /Co 3 O 4 delivers outstanding OER performance, achieving a current density of 10 mA cm −2 at an overpotential of merely 227 mV, alongside remarkable stability over 400 h. With an Ir content of merely 12.12 wt%, IrO x /Co 3 O 4 offers a mass activity of 977.75 mA mg Ir -1 at 1.5 V vs. RHE, which is 10.64 times that of unsupported IrO x , reflecting a significant improvement in the utilization efficiency of precious iridium. This work offers a straightforward yet effective strategy for designing high-performance, low‑iridium OER catalysts via support engineering.