2 + 1 > 3: Trimetallic Sites on the Zn-IrP2/FeP Electrode Trigger Synergistic Effect to Activate Industrial-Grade Performance for Hydrazine-Assisted Overall Water Splitting

Constructing multifunctional electrodes with high metal utilization by a one-step synthesis strategy is a serious challenge. Herein, Zn-IrP2/FeP with dual-functional activity induced by trimetallic sites are constructed by the "one-step phosphorization". Relevant characterizations and DFT calculations reveal that Ir and Fe act as the HER and HzOR sites, respectively, promoting the overall hydrazine splitting (OHzS) at the industrial-level current. Specially the Zn dopant, as an auxiliary active site for Ir–Fe dual-active sites, optimizes the physical structure, electronic configuration, d-band center, and adsorption intermediate capabilities of the Zn-IrP2/FeP/IF electrode from multiple perspectives. As expected, Zn-IrP2/FeP/IF only requires 223.0 and 382.0 mV to drive the industrial-grade current density of 1 A cm–2 for HER and HzOR, respectively. Notably, the voltage of the OHzS for Zn-IrP2/FeP/IF to reach 500 mA cm–2 is 1.38 V lower than that of the OWS. In summary, trimetallic sites exhibit synergetic electrocatalytic functions and synergistically maximize electrocatalytic efficiency. Moreover, the multiactive site mechanism of the dopant as an auxiliary active site is innovatively proposed in this work. This presents a valuable idea for designing multimetal catalysts with high metal utilization efficiency and in-depth investigation of catalytic mechanisms.