Solid-Polymer-Electrolyte Electrolysis of Urea Aqueous Solutions for Hydrogen Synthesis

This research proposed hydrogen production methods fromabundant organic resources and achieved the development of a high-activityelectrocatalyst. Urea is one of the promising hydrogen sources due toits high energydensity, safety, and abundance. In this paper, it was found that aNi/Ti-mesh anode prepared by the electrodeposition method exhibiteda high catalytic activity for electro-oxidation of urea/KOH aqueoussolutions, producing H-2, N-2, and CO2 using the solid-polymer-electrolyte (SPE) cell withan anion exchange membrane (Sustainion X-37). Significant H-2 evolution was observed with a good formation rate (260 & mu;molh(-1) cm(-2)) and j (15.4 mA cm(-2)) with a high Faradaic efficiency(93.7%) at a 1.50 V applied voltage in an SPE one-compartment cell. Only H-2 was obtained with a two-compartment SPE cell. Characterization studiesusing X-ray photoelectron spectroscopy, X-ray absorption fine structure,and scanning electron microscopy energy-dispersive spectroscopyrevealed that Ni(OH)(2) species was the active phase forthe urea oxidation at the Ni/Ti-mesh anode.