Anatase TiO2 nanoparticle coating on porous COK-12 platelets as highly active and reusable photocatalysts

Abstract

Nanoscale TiO₂ photocatalysts are widely used for biomedical applications, self-cleaning processes and wastewater treatments. The impregnation/deposition of TiO₂ nanoparticles is indispensable for facile handling and separation as well as the improvement of their photocatalytic performance. In the present study, ordered mesoporous COK-12 silica thin platelets with a high-aspect-ratio and rough surfaces are demonstrated as a potential nanoporous support for homogeneous TiO₂ nanoparticle coatings with high loading up to 16.7 wt%. The photocatalytic composite of COK-12 platelets and TiO₂ nanoparticles is characterized in detail by HRSEM, SAXS, XRD, N₂ physisorption analysis, solid-state UV-vis spectroscopy, HAADF-STEM, EDX analysis, and electron tomography. HAADF-STEM-EDX and electron tomography studies reveal a homogeneous dispersion of nanosized TiO₂ nanoparticles over COK-12 platelets. The final composite material with anatase TiO₂ nanoparticles that demonstrate a blueshifted semiconductor band gap energy of 3.2 eV coated on a highly porous COK-12 support shows exceptional photocatalytic catalytic activity for photodegradation of organic dyes (rhodamine 6G and methylene blue) and an organic pollutant (1-adamantanol) under UV light radiation, outperforming the commercial P25 TiO₂ (Degussa) catalyst.