Construction of Ultrafine PtIr Clusters Supported on Co 3 O 4 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 Co 3 O 4 nanoflowers assembled by nanowires (PtIr-Co 3 O 4 ). The encouraging performances in electrochemical OER and hydrogen evolution reaction (HER) are achieved over the PtIr-Co 3 O 4 catalyst, with the overpotentials as low as 410 and 237 mV at 100 mA cm -2 , respectively, outperforming the commercial IrO 2 and Pt/C catalysts. Due to the ultralow loading of PtIr clusters, the PtIr-Co 3 O 4 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 Co 3 O 4 nanoflowers enable the PtIr-Co 3 O 4 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.