Sulfur‐Stabilized Superfine Pt Clusters Synergized with Single‐Atom Ni‐N ₄ Sites for Hydrazine Oxidation‐Assisted Hydrogen Production

Hydrazine oxidation-assisted hydrogen evolution represents a promising avenue for energy-saving hydrogen production. However, the development of bifunctional catalysts with high atom economy and durability for both hydrazine oxidation reaction (HzOR) and hydrogen evolution reaction (HER) remains challenging. Here, a design is reported that combines sulfur-stabilized Pt clusters and Ni-N₄ sites on nitrogen-doped carbon support (Pt_n-S/Ni₁-NC) for boosting alkaline hydrazine oxidation-assisted hydrogen evolution. Experimental and theoretical results reveal that the pre-coordinated sulfur atoms on Pt clusters provide strong metal-support interaction (SMSI) for the homogeneous distribution of Pt clusters, allowing Pt clusters to remain ultrafine, which ensures high atom utilization and sufficient active sites. Moreover, the electronic interactions and synergistic adsorption mechanism of Pt clusters and adjacent Ni-N₄ sites markedly accelerate the H₂O dissociation and HzOR kinetics. As a result, the Pt_n-S/Ni₁-NC catalysts exhibit exceptional catalytic activity, achieving an ultrasmall HER overpotential of 19 mV and an ultralow HzOR working potential of -21 mV at 10 mA cm^-2 current density. In addition, the overall hydrazine oxidation-assisted splitting (OHzS) electrolyzer can reach 10 mA cm^-2 with a low cell voltage of 79 mV and good long-term stability in 1.0 m KOH/0.5 m N₂H₄.