Iridium 4 oxide powder

Cobalt (II) acetate tetrahydrate > 98.0%, copper (II) chloride dihydrate 99+%, titanium (IV) n-butoxide 99+%, and nickel (II) nitrate hexahydrate > 98.0% were purchased from Alfa Aesar (Kandel, Germany). Dopamine hydrochloride 100%, zinc (II) acetate dihydrate > 99.0%, iron (III) chloride 97%, potassium permanganate 99%, Nafion^® 5%wt solution, aqueous ammonia solution (30%), and sodium hydroxide 99.99% were purchased from Merck (Darmstadt, Germany). All aqueous solutions were prepared with ultrapure water (Milli-Q water, 18.2 MΩ cm). Platinum, nominally 20%, on carbon black and iridium (IV) oxide powder, 99%, purchased from Alfa Aesar, were used as benchmark catalysts.

Hydrogen tetrachloroaurate (III) trihydrate (HAuCl₄·3H₂O, 99.9%) and 5 wt% Nafion solution (∼5% in lower aliphatic alcohols and water, contains 15%–20% water) were purchased from Sigma-Aldrich. Iridium (III) chloride hydrate (IrCl₃·xH₂O, 99.9%) and Iridium (IV) oxide powder (IrO₂, 99%) were purchased from Alfa Aesar. Oleylamine (80%–90%) was purchased from Acros. Carbon black (Vulcan XC-72), commercial Pt/C (20% Pt on Vulcan XC-72) and commercial Ir/C (20% Ir on Vulcan XC-72) were purchased from Premetek. Cyclohexane (C₆H₁₂, A.R.), hexane (C₆H₁₄, A.R.), ethanol (C₂H₅OH, A.R.) and iso-propyl alcohol (C₃H₈O, A.R.) were purchased from Sinopharm Chemical Reagent Co. Ltd. All the chemicals were used as received without further purification. The water used in all experiments was ultrapure (Millipore, 18.25 MΩ/cm).