Pt-Loaded CoFe-Layered Double Hydroxides for Simultaneously Driving HER and HzOR

Hydrazine-assisted water electrolysis presents an energy-saving pathway for H2 production. However, due to the different electronic structure requirements for active metals in hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR) reactions, catalysts capable of simultaneously driving HER and HzOR are less studied. Herein, we employ an electrochemical deposition method to load 4.2 nm Pt nanoparticles onto CoFe-layered double hydroxides. The resultant Pt/CoFe/NF requires only 12.1 and 28.7 mV to achieve 50 and 100 mA cm–2 for HzOR and an ultralow overpotential of 16.5 mV with a Tafel slope of 31.4 mV dec–1 to achieve 10 mA cm–2 for HER. The Pt/CoFe/NF-based overall hydrazine splitting (OHzS) device can realize 10 and 100 mA cm–2 at low potential of 0.093 and 0.531 mV, respectively, and the Faradaic efficiency for both N2 and H2 generation reaches nearly 100%. Such HER and HzOR activities can be attributed to the electronic metal–support interaction (EMSI) between Pt and CoFe/NF, which modulates the d-band center of Pt to an optimal position, thereby balancing the adsorption of N2H4 molecules (ΔG*N2H4 = −2.27 eV) and the desorption of hydrogen (ΔGH* = −0.18 eV) by Pt/CoFe/NF. This work provides insights into the design of efficient bifunctional catalysts from the perspective of the electronic structure.