Institute of Fundamental Technological Research

The anodic substitution of a sluggish oxygen evolution reaction with a more energy-saving hydrazine oxidation reaction has the potential to greatly reduce energy consumption for hydrogen production. However, the underlying mechanism of the hydrazine oxidation reaction remains ambiguous, and the existing hydrazine splitting generally requires an external power source to drive the anodic and cathodic reactions, which is not suitable for outdoor applications. In this study, we have developed a heterostructure sulfide-based catalyst that effectively catalyzes both hydrazine oxidation and hydrogen evolution reactions. Through in situ Raman spectroscopy, we have confirmed that the breakage of the nitrogen-nitrogen single bond is a pathway for the hydrazine oxidation reaction. The enhanced electrocatalytic performance is attributed to the increased active sites and accelerated electron transfer within the heterostructures, which reduced the energy barrier, thereby enabling the fabricated electrolyzer using the g-C3N4/Ni(CN)2@NiS catalyst to deliver 200 mA cm−2 with a low voltage of 0.31 V. The assembled electrolyzer can be powered by a g-C3N4/Ni(CN)2@NiS anode-equipped direct hydrazine fuel cell, achieving self-powered hydrogen production with faradaic efficiency of more than 97 %.

Functional electrod, Carbon nitride, Hydrogen generation, Hydrazine