Pure Hydrogen Production by Aqueous Ethanol Electrolysis on Pt–Ru–O Anodes in a Solid Polymer Electrolyte Electrolysis Cell

Abstract

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.

Effects of Metal–Oxygen Coordination in Pt–Ru–Sn Electrocatalyst in the Electrochemical Reforming of Aqueous EtOH in a Solid-Polymer-Electrolyte Electrolysis Cell

“…Since Au 5p 1/2 also has an overlap with Pt 4f peaks, Pt was analyzed in the Pt 3p 3/2 region. 10 Solid-Polymer-Electrolyte Electrolysis Unit Preparation. Catalyst inks were prepared by ultrasonic homogenization of 8 mg of electrocatalyst powder, 400 μL of acetone, and 40 μL of Nafion solutions.…”

“…7−9 Hence, electrochemical reforming of aqueous EtOH by an SPE electrolysis cell is a promising route to utilize biomass. 10 EtOH is oxidized with water to CO 2 at the anode as the EtOH electro-oxidation reaction (EOR) and hydrogen is produced at the cathode as the hydrogen evolution reaction (HER). The EOR at the anode suffers from slow reaction rates, leading to high overpotentials.…”

“…The maximum n i is 12 for the complete oxidation to CO 2 and is determined by the product distribution. 10 n i 12 FE( ) 12…”

Paired Electrosynthesis of H2 and Acetic Acid at A/cm2 Current Densities

“…Currently, acetic acid is manufactured via the Monsanto process, 13 a homogeneous rhodium-catalyzed methanol carbonylation route which operates at high temper-atures (150−200 °C) and pressures (3−10 MPa) (Figure S1) and generates 1 ton of CO 2 emissions per ton of acetic acid. 12 Electrocatalytic approaches have been pursued in the production of acetic acid (Figure 1C), including via ethanol electrooxidation 8,14,15 (Table S2), carbon dioxide reduction (CO 2 R), 16−18 and carbon monoxide reduction (COR) 19−23 (Figure 1C). Most recently, pairing H 2 production and alcohol oxidation 14,24,25 has been advanced as a valorization strategy.…”

“…Electrocatalytic approaches have been pursued in the production of acetic acid (Figure C), including via ethanol electrooxidation ,, (Table S2), carbon dioxide reduction (CO 2 R), − and carbon monoxide reduction (COR) − (Figure C). Most recently, pairing H 2 production and alcohol oxidation ,, has been advanced as a valorization strategy.…”