Dual-phase cobalt phosphide/phosphate hybrid interactions via iridium nanocluster interfacial engineering toward efficient overall seawater splitting

Surface engineering and electronic modification are the two primary elements for improving the catalytic properties of electrode materials. We significantly improved the catalytic performances of interfacial-engineered Ir nanocluster-containing cobalt phosphide/phosphate heterostructured nanowires on nickel foam (Ir-Co2P/Co2P2O7 NWs/NF) in water splitting. The optimized Ir nanocluster content of 0.05 wt% resulted in a highly efficient catalytic performance, significantly outperforming commercial IrO2 and Pt-C catalysts. The Ir0.05-Co2P/Co2P2O7 NW bifunctional electrocatalyst displayed cell potentials of 1.52, 1.60, 1.62, and 1.67 V in 1.0 M KOH and mimic, simulated, and natural seawater, respectively, at 10 mA cm−2. DFT analysis confirmed that the heterostructure enrichment in the z-oriented d-orbital facilitates strong electronic interactions between the adsorbates and surfaces. The keys were the simultaneous generation of metal phosphide/phosphate via activation of the P site on the support. Furthermore, the electrocatalyst exhibited a solar-to-hydrogen efficiency of 22.4% in solar energy-aided water splitting, indicating that it is a viable, inexpensive candidate for use in water splitting.