Nafion 1100 w

Phosphoric acid (H₃PO₄, 85%), potassium sulfate (K₂SO₄, 99%), potassium bicarbonate (KHCO₃, 99.7%), potassium chloride (KCl, 99%), potassium hydroxide (KOH, 99.95%), copper nanoparticles (25 nm), Nafion^TM 1100 W (5 wt. % in a mixture of lower aliphatic alcohols and water) and isopropanol (IPA, 99%) were purchased from Sigma Aldrich and used as received. Titanium oxide nanoparticles (TiO₂, Aeroxide P25) were purchased from Fisher Scientific and used as received. The porous supports were also purchased from Fisher Scientific: 125 μm PVDF (0.45 μm pore size), 65 μm PTFE (0.44 μm pore size) and 16 μm PC (0.4 μm pore size). Nafion^TM 212, Nafion^TM XL, Fumasep (FAS-PET-130) and titanium (Ti) felt were purchased from Fuel Cell Store. Iridium(IV) chloride hydrate (Premion^®, 99.99%, metals basis, Ir 73% min) was purchased from Alfa Aesar. The water used in this study was 18 MΩ Milli-Q deionized- (DI-) water. Nafion membranes were activated through the following procedure: 1 h in 80 °C 1 M H₂SO₄—1 h in 80 °C H₂O₂—1 h in 1 M H₂SO₄—stored in DI-water. Fumasep was used as received and stored in 1 M KCl. Piperion (40 μm) was purchased from W7Energy and stored in 0.5 M KOH.

Potassium bicarbonate (KHCO₃, 99.7%), D-glucose (99.5%), copper nanoparticles (25 nm), Nafion^TM 1100 W (5 wt.% in a mixture of lower aliphatic alcohols and water) and Pt/C (40 wt.% Pt on Vulcan XC72) were purchased from Sigma Aldrich and used as received. Aquivion D79-25BS ionomer was purchased from Fuel Cell Store. Piperion (40 μm) was used as the anion-exchange membrane, purchased from W7Energy and stored in 0.5 M KOH. The water used in this study was 18 MΩ Milli-Q deionized- (DI-) water.

Lead solutions of desired concentrations were made from AAS standard solution of 1000 mg l⁻¹ Pb²⁺ in 2%–5% HNO₃ (Sigma-Aldrich, St. Louis, MO). Hydrochloric acid (HCl) solutions were prepared by diluting 34 ∼ 37% HCl (Trace Metal Grade, Fisher Chemicals) with de-ionized (DI) water. Potassium chloride solution (1 M) for preparation of the Ag/AgCl reference electrode was made by dissolving crystalline KCl (Fisher Scientific) in DI water. Perfluorinated resin solution containing Nafion 1100 W (5% in low aliphatic alcohols) and mesoporous carbon nanopowder (<500 nm particle size) were purchased from Sigma Aldrich. Unless otherwise specified, all other chemicals were obtained from Fisher Scientific.