not-yet-known not-yet-known not-yet-known unknown The hydrazine oxidation-assisted hydrogen generation system significantly expands the applicability of hydrogen production technology. However, the complex intermediate transformations involved in hydrazine oxidation reaction (HzOR) and hydrogen evolution reaction (HER) desperately in need of developing dual functional catalysts. Manipulating the d-band center of metal catalysts has been identified as one of the most effective approaches to enhance catalytic activity. Herein, Ir nanoparticles (NPs) anchored in B, N-codoped porous carbon (Ir@BNC) was developed and demonstrates excellent performances for both HER and HzOR in alkaline medium, achieving 10 mA cm-2 at -25 mV and 18 mV, respectively. The overall hydrazine splitting (OHzS) electrolyzer reaches 200 mA cm−2 with a cell voltage of just 0.68 V. The direct liquid N2H4/H2O2 fuel cell (DHHPFC) assembly with Ir@BNC can achieve a maximum power density of 199.2 mW cm-2 at room temperature. Furthermore, an H2 production system using an OHzS device powered by DHHPFC realizes hydrogen production at a stable rate (53.08 mol h-1 m-2). In-situ Raman tests and theoretical calculations unravel the metal-support interaction between Ir NPs and B, N-codoped porous carbon optimize the electronic structure and regulate the d-band center of Ir, thus promoting water dissociation and H2 desorption during the reaction process.