Ethanol c2h5oh

Ethanol (C₂H₅OH, Decon Labs, Inc.), ammonium heptmolybdate [(NH₄)₆Mo₇O₂₄·4H₂O, 98%, Sigma-Aldrich], nickel(II) nitrate hexahydrate (Ni(NO₃)₂·6H₂O, 98%, Sigma-Aldrich), iron (III) nitrate hexahydrate (Fe(NO₃)₃·9H₂O, 98%, Sigma-Aldrich), N, N Dimethylformamide [DMF, (CH₃)₂NC(O)H, anhydrous, 99.8%, Sigma-Aldrich], platinum powder (Pt, nominally 20% on carbon black, Alfa Aesar), iridium oxide powder (IrO2, 99%, Alfa Aesar), Nafion (117 solution, 5% wt, Sigma-Aldrich), sodium chloride (NaCl, Fisher Chemical), potassium hydroxide (KOH, 50% w/v, Alfa Aesar), and Ni foam (thickness: 1.6 mm, porosity: ~95%) were used as received. Deionized (DI) water (resistivity: 18.3 MΩ·cm) was used for the preparation of all aqueous solutions.

Nickel (II) nitrate hexahydrate [Ni(NO₃)₂·6H₂O, ≥ 97%, Sigma-Aldrich], ammonium molybdate tetrahydrate [(NH₄)₆Mo₇O₂₄·4H₂O, 81.0%–83.0% MoO₃ basis, Sigma-Aldrich], urea (Promega Corporation), sodium chloride (NaCl, Fisher Chemical), ethanol (C₂H₅OH, Decon Labs, Inc.), potassium hydroxide (KOH, 85%, pellets, ACS regent, Acros Organics), Pt/C (platium, nominally 20% on carbon black, Alfa Aesar), and hydrochloric acid (HCl, 36.5%–38.0% w/w, Fisher Chemical) were used without further purification. Ni foam (NF, thickness: 1.6 mm, porosity: ~ 95%) was used as the substrate for the preparation of all catalysts. NF was cleaned with 3 M HCl, ethanol, and deionized (DI) water several times before use. DI water was used to prepare solutions unless otherwise specified. Seawater was collected from Galveston Bay, Galveston, Texas, USA (29.303° N, 94.772° W) and was left standing for one week to allow the visible impurities to settle, after which the supernatant was collected before use. The white precipitates [mainly Ca(OH)₂ and Mg(OH)₂] produced during the preparation of alkaline natural seawater were removed by centrifugation at 7200 rpm for 5 min before use.