Zirconium oxychloride

The PS/silica composite fibers were dried overnight at 80 °C and then used for the synthesis of the ternary composite microtubes. 0.91 g cerium(III)chloride (2.5 mmol, Alfa Aesar, 99%) and 5.26 g zirconium oxychloride (16.7 mmol, Alfa Aesar, 99%) were dissolved separately in 20 mL of ethanol. The obtained solutions were mixed, stirred at 75 °C for 30 min, and left standing for 48 h at room temperature for aging. This sol was then deposited by spray-coating on the fibrous PS/silica composite material. After drying for 12 h at 60 °C the composite material was finally calcined at 750 °C for 4 h (oven Heraeus Instr., thermocon P^®).

Yttrium nitrate hexahydrate (Y(NO₃)₃·6H₂O, 99.98%, Sigma Aldrich), Ammonium niobate oxalate hydrate (NH₄NbO(C₂O₄)₂·xH₂O, 99.99%, Sigma Aldrich), Zirconium oxychloride (ZrOCl₂·xH₂O, 99.9%, Alfa Aesar), Ruthenium chloride hydrate (RuCl₃·xH₂O, Ru 40–49%, Sigma Aldrich), Rhodium chloride hydrate (RhCl₃·xH₂O, Rh 38∼40%, Sigma Aldrich), Urea (CH₄N₂O, ≥99%, Sigma Aldrich), Ethylene glycol (HOCH₂CH₂OH, 99%, Sigma Aldrich), and Polyvinyl pyrrolidone -PVP ((C₆H₉NO)_n, MW = 55 kDa, Sigma Aldrich). All reagents are used as received, without further purification.