Potassium hexachloroplatinate 4

Dimethylformamide (DMF), trichloracetic acid (TCA), horseradish peroxidase (HRP) (type VI, ≥250 units/mg), catalase (from bovine liver, 2,000–5,000 units/mg), 4-aminoantipyrine (4-AP), phenol, graphene oxide (GO), activated charcoal, agar powder, potassium chloride, silver nitrate, potassium hexachloroplatinate (IV), gold(III) chloride trihydrate, aceton, 2-isopropanol, ethanol, and other chemicals were purchased from Sigma-Aldrich (St. Louis, United States). All reagents were of analytical grade. Mn(III) meso-tetra(N-methyl-4-pyridyl) porphine pentachloride (MnTMPyP) and Mn(III) meso-tetra(4-pyridyl) porphine chloride (MnTPyP) (>95%) were obtained from Frontiers Scientific Inc. Phosphate buffer (PB) solutions (0.1 M, pH 7.4) were prepared from disodium hydrogen phosphate and sodium dihydrogen phosphate. The pH of the solutions was controlled by the pH-meter 765 (Knick GmbH). All solutions were prepared using a Milli-Q water purification system (Merk KGaA, Germany).

Sulfuric acid (H₂SO₄, 98%), nitric acid (HNO₃, 70%), toluene (C₇H₈, 99.5%), ethylenediamine (C₂H₈N₂, ˃99%), acetone (C₃H₆O, 99.9%), methanol (C₂H₄O, 99.9%), and ethanol anhydrous (CH₃CH₂OH, 99.9%) were acquired from Fisher Scientific. Sodium borohydride (NaBH₄, ≥96%), ferrocene (C₁₀H₁₀Fe, 98%), Nafion^® 5% v/v solution (C₇HF₁₃O₅S·C₂F₄, 95%), cobalt chloride (II) (CoCl₂·2H₂O), and potassium hexachloroplatinate (IV) (K₂PtCl₆, 99+%) were supplied by Sigma Aldrich (St. Louis, MO, US). Hydrogen ultra-high-purity grade (99.999%), argon ultra-high-purity grade (99.999%), nitrogen industrial-grade purity (99.985%), and carbon monoxide compressed (99.9%) were purchased from Infra. All solutions were prepared with deionized water (milliQ grade, 18 MΩ).

Melamine, glucose, sodium
oxalate, potassium hexachloroplatinate(IV), palladium(II) chloride,
and potassium gold(III) chloride were purchased from Sigma-Aldrich
and used without further purification. Sodium acetate trihydrate was
purchased from BDH Chemicals Ltd. Triton X-100 (C₁₄H₂₂O(C₂H₄O)₁₀) was obtained
from Biomol GmbH. PIM-1,^{56 (link)} PIM-EA-TB,^{57 (link)} and g-C₃N₄^{58 (link)} were prepared following literature recipes.
Ultrapure (18.2 MΩ cm at 18 °C) water from a Thermo Fisher
water purification system was used for all solutions.