Wettability, Photoactivity, and Antimicrobial Activity of Glazed Ceramic Tiles Coated with Titania Films Containing Tungsten

Abstract

Self-cleaning coatings are advanced materials for the removal of pollutants and microorganisms by combining wettability, photocatalytic degradation, and antimicrobial activity. In this work, we propose a rational design of self-cleaning films based on TiO2 synthesized by sol–gel on commercial glazed ceramic tiles for building’s indoor applications. The synthesis strategy is based on hydrolysis and condensation of Ti-isopropoxide in the presence of W­(VI) precursors to tune defects and crystallinity of the resulting W–TiO2 thin film. From the microstructure and surface composition analysis for different tungsten contents and annealing temperatures, we conclude that the film is composed by sintered TiO2 particles with adsorbed polytungstates (WO x ) that inhibit anatase/rutile transformation. Polytungstates on TiO2 also induce surface defects that enhance water contact angle and inactivation of Escherichia coli under visible light. The presence of W­(VI) has a negligible effect toward crystal violet degradation either under visible or under UV light. These results provide evidence on the existence of at least two different types of defects: (i) intrinsic defect from a sol–gel route and (ii) induced defect by tungsten species on the surface. Understanding the correlation between composition, structure, and self-cleaning properties provides a base for an efficient design of low-cost self-cleaning ceramic tiles that can be fully manufactured in an industrial plant.

Role of Rare Earth Elements and Entropy on the Anatase-To-Rutile Phase Transformation of TiO2 Thin Films Deposited by Ion Beam Sputtering

“…Titanium dioxide (TiO 2 ) has attracted much attention in recent decades because of its applicability in areas such as pigments, optical sensors, (photo)catalysis, 1,2 ferromagnetic Fe−N-codoped TiO 2 nanotubes, 3,4 graphene-TiO 2 composites, 5 antimicrobial activity, 6 and optoelectronic devices. 7−17 Usually, TiO 2 can be found in the brookite (orthorhombic symmetry), anatase (tetragonal), and rutile (tetragonal) crystalline structureswith the last two being the most common and interesting structures for the abovementioned applications.…”

Metalloporphyrins into Mesoporous Photonic Crystals: Towards Nanostructured Sensing Devices

“…It is worth noticing that the band position inside the pores remained the same as in solution, reflecting that MP is bound through electrostatic interactions and not by coordination to Mn(III) nor self-assembly aggregation on the surface [15]. In fact, electrostatic interactions are expected to play a major role, since MP has a net positive charge, and TiO2 and SiO2 surfaces are negatively charged at pH 7 [26,27]. UV-Vis spectroscopy was useful, not only to characterize the hybrid material, but also to estimate the amount of MP adsorbed in the film.…”

Chain-like uranyl-coordination polymer as a bright green light emitter for sensing and sunlight driven photocatalysis

“…This configuration with continuum emission between 400 and 600 nm and 2700 μW•cm −2 (λ max = 520 nm) irradiance is referred to as sunlight-like irradiation. 17 The Xe lamp spectrum in this configuration could be found elsewhere. 16…”