We investigated the synergy of Ru and Pt as anodes for pure hydrogen production via electrolysis of aqueous ethanol in a solid polymer electrolysis cell. Ketjenblack-supported Pt−Ru−O anodes prepared by NaBH 4 reduction (Pt−Ru/KB) were tested for the ethanol electrooxidation reaction (EOR). 100% H 2 selectivity in a Pt/KB cathode was achieved. A drastic enhancement of around 4 times in steady-state current density was observed in Pt−Ru/KB compared to Pt/KB at a cell voltage of 0.6 V even at an Ru loading of just 1% was demonstrated. Product selectivity at the anode was measured to determine the ethanol utilization efficiency which was found to be around 20% or 1.2 mol H2 •mol EtOH −1 . X-ray absorption fine structure (XAFS), X-ray diffraction (XRD), and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDS) were conducted to characterize the Pt−Ru/KB catalysts. Cyclic voltammetry studies were performed for EOR. On the basis of the results of the characterization and electrochemical studies, an alternative EOR mechanism for the synergy of Ru and Pt at lower potentials is proposed.

The electrooxidation kinetics of ethanol is key to making direct ethanol fuel cells and electrocatalytically reforming ethanol viable technologies for a more sustainable energy conversion. In this study, the electrooxidation of ethanol was investigated on nickel hydroxide (Ni(OH)2) catalysts synthesized using a facile solvothermal method. Variations in the temperature, heating time, and the addition of oleylamine in the precursor enabled the phase and morphology control of the catalysts. X-ray diffraction and scanning electron microscopy show that the addition of oleylamine in the precursor resulted in microspheres with a high surface area, but favored the formation of β-phase Ni(OH)2. Elevated temperatures or prolonged periods of heating in a controlled environment, on the other hand, can lead to the formation of the ethanol oxidation reaction-active α-phase. Among the synthesized catalysts, the α-Ni(OH)2 microspheres with nanoflakes achieved the highest activity for ethanol oxidation with a current density of 24.4 mA cm−2 at 1.55 V (vs. RHE, reversible hydrogen electrode) in cyclic voltammetry tests and stable at 40 mA cm−2 in chronoamperometric tests at the same potential, comparatively higher than other Ni-based catalysts found in the literature. While the overpotential is beyond the useful range for direct ethanol fuel cells, it may be useful for understanding the mechanism of ethanol oxidation reactions on transition metal hydroxides at their oxidizing potential for ethanol electroreforming.