2 + 1 > 3: Trimetallic\nSites on the Zn-IrP<sub>2</sub>/FeP Electrode Trigger Synergistic\nEffect to Activate Industrial-Grade\nPerformance for Hydrazine-Assisted Overall Water Splitting

Constructing multifunctional electrodes with high metal\nutilization\nby a one-step synthesis strategy is a serious challenge. Herein, Zn-IrP<sub>2</sub>/FeP with dual-functional activity induced by trimetallic\nsites are constructed by the “one-step phosphorization”.\nRelevant characterizations and DFT calculations reveal that Ir and\nFe act as the HER and HzOR sites, respectively, promoting the overall\nhydrazine splitting (OHzS) at the industrial-level current. Specially\nthe Zn dopant, as an auxiliary active site for Ir–Fe dual-active\nsites, optimizes the physical structure, electronic configuration,\nd-band center, and adsorption intermediate capabilities of the Zn-IrP<sub>2</sub>/FeP/IF electrode from multiple perspectives. As expected,\nZn-IrP<sub>2</sub>/FeP/IF only requires 223.0 and 382.0 mV to drive\nthe industrial-grade current density of 1 A cm<sup>–2</sup> for HER and HzOR, respectively. Notably, the voltage of the OHzS\nfor Zn-IrP<sub>2</sub>/FeP/IF to reach 500 mA cm<sup>–2</sup> is 1.38 V lower than that of the OWS. In summary, trimetallic sites\nexhibit synergetic electrocatalytic functions and synergistically\nmaximize electrocatalytic efficiency. Moreover, the multiactive site\nmechanism of the dopant as an auxiliary active site is innovatively\nproposed in this work. This presents a valuable idea for designing\nmultimetal catalysts with high metal utilization efficiency and in-depth\ninvestigation of catalytic mechanisms.