Preparation of Visible-Light Active Oxygen-Rich TiO2 Coatings Using Low Pressure Cold Spraying

Abstract

Visible-light active photocatalysts in the form of coatings that can be produced using large-scale methods have attracted considerable attention. Here we show a facile approach to deposit coatings using the low pressure cold spray (LPCS) from oxygen-rich amorphous titanium dioxide, which is a structurally-unconventional feedstock powder for LPCS. We synthesized amorphous TiO2, in which we introduced numerous defects, such as oxide groups (peroxy and superoxy) in volume and hydroxyl groups on the surface. Then we deposited as-prepared powder preserving the presence of active groups, which we demonstrated using Raman spectroscopy. To show the activity of the prepared coatings, we perform methylene blue degradation under visible light. Our research shows that it is worth considering the internal atomic structure and surface chemistry of the powders to be preserved after low pressure cold spraying.

A Composite of TiO2 Quantum Dots and TiO2 Nanoparticles Coated on Anti-Bumping Glass Beads (TiO2QDs-TiO2NPs/GBs), with a Very Low Content of TiO2 as a High Performance Photocatalyst

“…It is shown that the slight decrease in the bandgap could be the result of oxygen vacancies and titanium ions present in the sample. In addition, it is stated that the more defected state would lower the bandgap even more [28][29][30][31]. In this study, the narrowing of the bandgap of coated catalysts compared to that of TiO 2 NPs and TiO 2 QDs may be directly related to the defected state of TiO 2 NPs, TiO 2 QDs, and TiO 2 NPs-TiO 2 QD composites induced by coating on the surface of GBs.…”