Efficient Hydrazine‐Assisted Hydrogen Production via Tailoring Electron Injection Into Metallic Co Sites

ABSTRACT Regulating the d‐orbital electron configuration of metallic Co to achieve bifunctional hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR) is highly desirable for energy‐saving H 2 production. Although interface engineering and heteroatom doping can modulate the electronic structure of Co sites, most interfaces still feature a unidirectional electric field and furthermore, corresponding compounds tend to form after heteroatom doping, compromising controllability of modulation. Herein, P‐(Co/ZnO)/F‐Ni electrocatalyst with a reverse dual‐interfacial electric field and unsaturated P─Co bonds is established, aiming to tailor d‐orbital electronic structure of Co sites, and thereby optimizing adsorption and activation of H 2 O and N 2 H 4 during HER and HzOR. Both experimental results and theoretical calculations reveal that the modulated electron injection of Co sites should be responsible for the facilitated HER and HzOR processes through moderate Co‐*H 2 O and Co‐*N 2 H 4 binding strengths. Notably, this approach endows P‐(Co/ZnO)/F‐Ni with superior HER and HzOR performance, achieving working potentials of −105.3 and −41.2 mV at industrial‐level current density of 1000 mA cm −2 for HER and HzOR, respectively. Furthermore, the assembled two‐electrode cell requires a cell voltage of 0.33 V at 500 mA cm −2 . The present work provides a novel strategy for modulating the d‐orbital electron configuration of metals to realize energy‐saving bifunctional applications.