Coating of expanded polystyrene spheres by TiO2 and SiO2–TiO2 thin films

• Published in: Journal of materials research Vol. 39; no. 10; pp. 1473 - 1488
• Main Authors: Miądlicki, Piotr, Rychtowski, Piotr, Tryba, Beata
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 28-05-2024; Springer Nature B.V
• Subjects: Ammonia; Applied and Technical Physics; Biomaterials; Chemistry and Materials Science; Coating; Evaporation; Evaporators; Fluidized beds; Inorganic Chemistry; Materials Engineering; Materials Science; Nanotechnology; Photocatalysis; Polystyrene resins; Silicon dioxide; Sol-gel processes; Tetraethyl orthosilicate; Thin films; Titanium dioxide; Core/shell; EPS/TiO; EPS/SiO; TiO; Photocatalytic bed; Titanium dioxide
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/s43578-024-01319-3

Expanded polystyrene spheres (EPS) were coated by SiO
2
–TiO
2
or TiO
2
for application as a fluidized bed in the photocatalytic reactor. Silica coating was realized by the sol–gel process carried out in a vacuum evaporator at 60–70 °C. The most uniform and thin layer of silica coating was obtained by the Stöber method based on the hydrolysis of tetraethyl orthosilicate (TEOS) catalysed by an ammonia solution. Effective TiO
2
coating was obtained by the immersion of EPS in the titania aqueous suspension and evaporation of water in a vacuum evaporator. Heating of EPS spheres coated by SiO
2
, TiO
2
or SiO
2
–TiO
2
at the temperatures of 120–140 °C resulted in a shrinkage of their volume. For the thick layer coating, a strong corrugation of EPS surface was observed. The photocatalytic tests showed, that highly corrugated surface of coated EPS slowed down ethylene decomposition, whereas a thin layer coating of both, SiO
2
and TiO
2
was advantageous.
Graphical abstract