Glycerin

The following chemical reagents were used to produce the nanocomposites: chitosan (high molecular weight: 310,000–375,000 Da; degree of deacetylation > 75%) from shrimp shells (Sigma-Aldrich, Poznań, Poland), sodium alginate (Sigma-Aldrich, Poznań, Poland), acetic acid (99,5%, Chempur, Piekary Śląskie, Poland), glycerin (99.5%, Chempur, Piekary Śląskie, Poland), deionised water, extra virgin olive oil, ozonated extra virgin olive oil (with an ozone content of 1.11 ± 0.02 g in 100 g of oil, Scandia Cosmetics, Niepolomice, Poland) and dried hibiscus flower calyx (Agnex, Białystok, Poland).

Trisodium citrate dihydrate, silver nitrate, potassium chloride, ethylene glycol and acetone were purchased from POCH S.A. (Gliwice, Poland). Sodium sulphide was acquired from Sigma-Aldrich (St. Louis, MO, USA). Polyvinylpyrrolidone (PVP) with an average molar mass of ca. 4 × 10⁴ g mol⁻¹ was purchased from Fluka (Seelze, Germany). Glycerin and ammonium fluoride were purchased from Chempur (Piekary Slaskie, Poland). Pyridine was purchased from Ubichem (Eastleigh, UK). All of the chemicals were used without further purification or treatment. The water was purified by a Millipore Milli-Q system and had a resistivity of ca. 18 MΩ cm⁻¹. The silver used as a material for electrodes was purchased from the Polish Mint (Warsaw, Poland). Titanium foil of 0.25 mm thick and 99, 5% purity was purchased from Alfa Aesar (Kandel, Germany). It was cut into 1 cm² round plates. The plates were cleaned ultrasonically with acetone and ethanol, rinsed with deionized (DI) water, and dried in air.