Naoh pellets

Pyrrole (Aldrich) was kept below 5 °C in the absence of light. Anhydrous FeCl₃ 98% (Aldrich), 3-triethoxysilylpropylamine (APTES, 99%, Aldrich), FeCl₂·4H₂O (Aldrich), titanium n-butoxide (Sigma Aldrich, TBOT), NaOH pellets (LobaChemie, India) were used as received. NH₄OH solution (25 wt%), silver nitrate (BDH, UK), sodium boron hydride (NaBH₄) (Johnson Matthey, UK), 4-nitrophenol (PNP) (Sigma Aldrich), and methylene blue (MB) were used without further purification.

Zinc nitrate hexahydrate (Zn(NO₃)₂·6H₂O, 99% Sigma-Aldrich), 5-fluorouracil (99% Sigma-Aldrich), sodium carbonate (Na₂CO₃, 99% Sigma-Aldrich), CS (Acros, USA, with a molecular weight: 100 000–300 000, degree of deacetylation = 80%), vanillin (Vn, 99% Sigma-Aldrich), graphite powder ((1–2 μm), Aldrich, Milwaukee, WI, USA), nujol oil (Sigma, d = 0.84 g mL⁻¹), zirconium(iv) butoxide (Sigma-Aldrich), Pluronic® P123 (Sigma-Aldrich), cobalt nitrate hexahydrate Co(NO₃)₂·6H₂O (Sigma-Aldrich), NaOH pellets (Loba Chemie, India), KH₂PO₄ and K₂HPO₄ (Pure Laboratory Chemicals, Egypt), hydrochloric acid, acetic acid and ethanol (Adwic, Egypt) were utilized as received without further purification.