Zinc nitrate hexahydrate

Cupric Acetate Monohydrate (Cu(acac)₂, 99%, Alfa Aesar), 2-methylimidazole (Acros), sulfur powder (325 mesh, 99.5%, Alfa), commercial Pt/C (20 wt% metal, Alfa Aesar), zinc nitrate hexahydrate (98%, Alfa Aesar), KOH (analytical grade, Sinopharm Chemical), carbon tetrachloride (innochem), analytical grade methanol (Sinopharm Chemical), Nafion D-521 dispersion (Alfa Aesar), N, N-dimethylformamide (DMF) (Sinopharm Chemical) were used without any further purification. The distilled water with a resistivity of 18.2 MΩ cm⁻¹ was used in all experiments.

Horseradish peroxidase (HRP) (reagent grade), Candida antarctica lipase (CALB), 2-methylimidazole, phosphate buffer saline (1×), 1,2,3-trihydroxybenzene (THB, ACS reagent), and 4-nitrophenyl butyrate (p-NPB) were purchased from Sigma-Aldrich. Zinc nitrate hexahydrate (99.998%) and hydrogen peroxide (29–32% wt) were purchased from Alfa Aesar. Cytochrome c from horse heart was purchased from Biodee Corporation. All the other reagents are of analytic grade.

Calcium nitrate tetrahydrate [Ca(NO₃)₂∙4H₂O, Aldrich St. Louis, MO, USA], phosphorus pentoxide (P₂O₅, 98%, Merck, Kenilworth, NJ, USA), silver nitrate (AgNO₃, 99.9%, Alfa Aesar, Ward Hill, MA, USA) and zinc nitrate hexahydrate (Zn(NO₃)₂∙6H₂O, 99%, Alfa Aesar, Ward Hill, MA, USA) were used as precursors for the synthesis of HAp, Ag:HAp and Zn:HAp thin films. All the precursors were used without further purification. Vinyl polydimethylsiloxane (PDMS, M_w ≈ 25,000, Sigma Aldrich, St. Louis, MO, USA) liquids were used as precursors for PDMS layers generation. Commercially pure titanium (Ti, 1.0 mm thick, Alfa Aesar, Ward Hill, MA, USA) foil was cut into disks with a 20 mm diameter and were used as substrates. All the disks were degreased (five time) in an ultrasonic bath with acetone. After each degreasing the disks were rinsed with deionized water.

The chemical reagents include natural graphite powder (200 mesh, UniRegion Bio-Tech, Hsinchu, Taiwan), zinc nitrate hexahydrate (99%, Alfa Aesar, Haverhill, MA, USA), ferric nitrate nonahydrate (98%, Sigma-Aldrich, St. Louis, MO, USA), sodium hydroxide (95%, Nihon Shiyaku Reagent, Kyoto, Japan), sulfuric acid (99.99%, Nihon Shiyaku Reagent, Kyoto, Japan), acetone (95%, Nihon Shiyaku Reagent, Kyoto, Japan), hydrochloric acid (37%, Union Chemical, Hsinchu, Taiwan), potassium permanganate (99.3%, Union Chemical, Hsinchu, Taiwan), sodium nitrate (99.5%, Hayashi Pure Chemical Ind, Osaka, Japan), hydrogen peroxide (30%, Showa Chemical, Tokyo, Japan), and methylene blue (99%, Koch-Light Laboratories, Ltd., Haverhill, Suffolk, UK). GO was prepared via modified Hummer’s method. The purity of the chemicals used in this experiment is of analytical grade, and they were used directly without any treatment.

2-methylimidazole (Hmim) (99% purity), zinc nitrate hexahydrate (99 + % purity) and 2-propanol (99 + %) were purchased from Alfa Aesar, absolute ethanol (99.8 + % purity) was purchased from Fisher Scientific.

For the synthesis of ZIF-8, 2-methylimidazole (Hmim) (99% purity) and zinc nitrate hexahydrate (99+% purity) were purchased from Alfa Aesar and absolute ethanol (99.8+% purity) was purchased from Fisher Scientific. For the fabrication of the HF membranes, Fumion AP poly(2,2′-(m-phenylene))-5,5′-bisbenzimidazole (PBI, M_w = 48 000 g mol⁻¹) was supplied by Fumatech BWT GmbH. Polyvinylpyrrolidone (PVP) K30, anhydrous N-methylpyrrolidone (NMP, 99.5% purity) and lithium chloride (LiCl) were purchased from Sigma-Aldrich. n-Hexane and methanol were purchased from Fisher Scientific.