Jonathan Watté
Ghent University
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Publication
Featured researches published by Jonathan Watté.
ACS Applied Materials & Interfaces | 2016
Jonathan Watté; Petra Lommens; Glenn Pollefeyt; Mieke Meire; Klaartje De Buysser; Isabel Van Driessche
In this work, we present preparation and stabilization methods for highly crystalline TiO2 nanoparticle suspensions for the successful deposition of transparent, photocatalytically active TiO2 thin films toward the degradation of organic pollutants by a low temperature deposition method. A proof-of-concept is provided wherein stable, aqueous TiO2 suspensions are deposited on glass substrates. Even if the processing temperature is lowered to 150-200 °C, the subsequent heat treatment provides transparent and photocatalytically active titania thin layers. Because all precursor solutions are water-based, this method provides an energy-efficient, sustainable, and environmentally friendly synthesis route. The high load in crystalline titania particles obtained after microwave heating opens up the possibility to produce thin coatings by low temperature processing, as a conventional crystallization procedure is in this case superfluous. The impact of the precursor chemistry in Ti(4+)-peroxo solutions, containing imino-diacetic acid as a complexing ligand and different bases to promote complexation was studied as a function of pH, reaction time and temperature. The nanocrystal formation was followed in terms of colloidal stability, crystallinity and particle size. Combined data from Raman and infrared spectroscopy, confirmed that stable titanium precursors could be obtained at pH levels ranging from 2 to 11. A maximum amount of 50.7% crystallinity was achieved, which is one of the highest reported amounts of anatase nanoparticles that are suspendable in stable aqueous titania suspensions. Decoloring of methylene blue solutions by precipitated nanosized powders from the TiO2 suspensions proves their photocatalytic properties toward degradation of organic materials, a key requisite for further processing. This synthesis method proves that the deposition of highly crystalline anatase suspensions is a valid route for the production of photocatalytically active, transparent films on heat-sensitive substrates such as polymers.
Environmental science. Nano | 2016
E. Van Eynde; Z.-Y. Hu; Tom Tytgat; Sammy W. Verbruggen; Jonathan Watté; G. Van Tendeloo; I. Van Driessche; Ronny Blust; Silvia Lenaerts
We present a green, biological production route for silica–titania photocatalysts using diatom microalgae. Diatoms are single-celled, eukaryotic microalgae (2–2000 μm) that self-assemble soluble silicon (Si(OH)4) into intricate silica cell walls, called frustules. These diatom frustules are formed under ambient conditions and consist of hydrated silica with specific 3D morphologies and micro–meso or macroporosity. A remarkable characteristic of diatoms is their ability to bioaccumulate soluble titanium from cell culture medium and incorporate them into their nanostructured silica cell wall. Controlled cultivation of the diatom Pinnularia sp. on soluble titanium in a batch process resulted in the biological immobilisation of titanium dioxide in the porous 3D architecture of the frustules. Six different titanium sources are tested. The silica–titania frustules were isolated by treating the harvested Pinnularia cells with nitric acid (65%) or by high temperature treatment. Thermal annealing converted the amorphous titania into crystalline titania. The produced silica–titania material is evaluated towards photocatalytic activity for acetaldehyde (C2H4O) abatement. Frustules cultivated with TiBaldH showed the highest photocatalytic performance. Comparison of the photocatalytic activity with P25 reveals that P25 has a 4 fold higher photocatalytic activity, but when photocatalytic activity is normalized for titania content, the frustules show double activity. Further material characterization (morphology, crystallinity, surface area and elemental distribution) of the TiBaldH silica–titania frustules provides additional insight into their structure–activity relationship. These natural biosilica–titania materials have excellent properties for photocatalytic purposes, including high surface area (108 m2 g−1) and good porosity, and show reliable immobilization of TiO2 in the ordered structure of the diatom frustule.
Materials | 2018
Matthias Van Zele; Jonathan Watté; Jan Hasselmeyer; Hannes Rijckaert; Yannick Vercammen; Steven Verstuyft; Davy Deduytsche; Damien P. Debecker; Claude Poleunis; Isabel Van Driessche; Klaartje De Buysser
The thickness characterization of transparent protective coatings on functional, transparent materials is often problematic. In this paper, a toolbox to determine the thicknesses of a transparent coating on functional window films is presented. The toolbox consists of a combination of secondary ion mass spectrometry and profilometry and can be transferred to other transparent polymeric materials. A coating was deposited on designed model samples, which were characterized with cross-sectional views in transmission and in scanning/transmission electron microscopy and ellipsometry. The toolbox was then used to assess the thicknesses of the protective coatings on the pilot-scale window films. This coating was synthesized using straightforward sol-gel alkoxide chemistry. The kinetics of the condensation are studied in order to obtain a precursor that allows fast drying and complete condensation after simple heat treatment. The shelf life of this precursor solution was investigated in order to verify its accordance to industrial requirements. Deposition was performed successfully at low temperatures below 100 °C, which makes deposition on polymeric foils possible. By using roll-to-roll coating, the findings of this paper are easily transferrable to industrial scale. The coating was tested for scratch resistance and adhesion. Values for the emissivity (ε) of the films were recorded to justify the use of the films obtained as infrared reflective window films. In this work, it is shown that the toolbox measures similar thicknesses to those measured by electron microscopy and can be used to set a required thickness for protective coatings.
Journal of Sol-Gel Science and Technology | 2013
Melis Arin; Jonathan Watté; Glenn Pollefeyt; K. De Buysser; I. Van Driessche; Petra Lommens
ACS Applied Materials & Interfaces | 2016
Jonathan Watté; Wouter Van Gompel; Petra Lommens; Klaartje De Buysser; Isabel Van Driessche
THE Coatings | 2018
Jonathan Watté; Matthias Van Zele; Klaartje De Buysser; Isabel Van Driessche
Archive | 2017
Jonathan Watté
19th International Sol-Gel conference (Sol-Gel 2017) | 2017
Jonathan Watté; Klaartje De Buysser; Isabel Van Driessche
19th International Sol-Gel conference (Sol-Gel 2017) | 2017
Jonathan Watté; Matthias Van Zele; Isabel Van Driessche; Klaartje De Buysser
Nanocoatings, NC3 Workshop, Abstracts | 2015
Jonathan Watté; Petra Lommens; Klaartje De Buysser; Isabel Van Driessche