Construction of Ultrafine PtIr Clusters Supported on Co₃O₄ Nanoflowers for Enhanced Overall Water Splitting

Green hydrogen production through electrochemical overall water splitting has suffered from sluggish oxygen evolution reaction (OER) kinetics, inferior conversion efficiency, and high cost. Herein, ultrafine PtIr clusters are synthesized via an electrodeposition method and decorated on the Co₃O₄ nanoflowers assembled by nanowires (PtIr-Co₃O₄). The encouraging performances in electrochemical OER and hydrogen evolution reaction (HER) are achieved over the PtIr-Co₃O₄ catalyst, with the overpotentials as low as 410 and 237 mV at 100 mA cm^-2, respectively, outperforming the commercial IrO₂ and Pt/C catalysts. Due to the ultralow loading of PtIr clusters, the PtIr-Co₃O₄ catalyst exhibits 1270 A g_Ir ^-1 for OER at the overpotential of 400 mV. Our detailed analyses also show that the strong interactions between the ultrafine PtIr clusters and the Co₃O₄ nanoflowers enable the PtIr-Co₃O₄ catalyst to afford 10 mA cm^-2 for the overall water splitting at the potential of 1.57 V, accompanied by high durability for 100 h.