Reference : Acid acting as redispersing agent to form stable colloids from photoactive crystallin...
Scientific journals : Article
Engineering, computing & technology : Materials science & engineering
Engineering, computing & technology : Chemical engineering
http://hdl.handle.net/2268/226690
Acid acting as redispersing agent to form stable colloids from photoactive crystalline aqueous sol–gel TiO2 powder
English
Mahy, Julien mailto [Université de Liège - ULiège > Department of Chemical Engineering > Department of Chemical Engineering >]
Deschamps, Fabien mailto [Université de Liège - ULiège > Department of Chemical Engineering > Ingéniérie électrochimique >]
Collard, Valérie mailto [University of Liège (ULiège), Complex and Entangled Systems from Atoms to Materials (CESAM), Center for Education and Research on Macromolecules (CERM) > > > >]
Jérôme, Christine mailto [University of Liège (ULiège), Complex and Entangled Systems from Atoms to Materials (CESAM), Center for Education and Research on Macromolecules (CERM) > > > >]
Bartlett, John []
Lambert, Stéphanie mailto [Université de Liège - ULiège > Department of Chemical Engineering > Department of Chemical Engineering >]
Heinrichs, Benoît mailto [Université de Liège - ULiège > Department of Chemical Engineering > Génie chimique - Nanomatériaux et interfaces >]
2018
Journal of Sol-Gel Science and Technology
Kluwer Academic Publishers
87
568-583
Yes (verified by ORBi)
International
0928-0707
1573-4846
Netherlands
[en] Aqueous TiO2 sol-gel synthesis ; Redispersion property ; Photocatalysis ; Recycling ; Fe doping ; Colloid stability
[en] In this work, the redispersion of three nanocrystalline TiO2 colloids is studied: one pure and two Fe-doped titania. These three colloids are produced by an easy aqueous sol-gel synthesis using precipitation-acidic peptization of Ti precursor. For the two Fe-doped TiO2, one is doped during synthesis (primary doping) and the other is doped after the synthesis (secondary doping). The initial colloids are composed of crystalline TiO2 particles around 7 nm with good photocatalytic properties, tested on PNP degradation under visible light (wavelength > 390 nm).
The powders obtained by air drying of these three colloids are redispersed in water to produce colloids which are compared to the initial colloid produced. For each colloid, 5 cycles of drying-redispersion are achieved. The colloids are characterized by dynamic light scattering, zeta potential measurements, inductively coupled plasma–atomic emission spectroscopy, X-ray diffraction, nitrogen adsorption-desorption measurements, Mössbauer spectroscopy, diffuse reflectance spectroscopy, and photocatalytic tests. The results show that similar products are obtained between the cycles, maintaining homologous properties of colloids. This property of redispersion is mainly due to the acid (HNO3, HCl, or H2SO4) which protonates the surface of the TiO2 nanoparticle leading to high surface charges and electrostatic repulsions between aggregates. This property can be very useful for industrial applications of this synthesis, especially as it allows the volume and weight to be reduced for transportation and storage. Moreover, results show that the pure TiO2 powder can be doped during its redispersion step. The redispersion of the TiO2 developed here is possible without surface functionalization or multiple step processes, contrary to commercial Degussa P25. A two year stability study of all the produced colloids has been performed by following the evolution of the macroscopic aspect and the physico-chemical properties of these sols. This study showed high stability of the produced colloids.
Complex and Entangled Systems from Atoms to Materials (CESAM) ; Center for Education and Research on Macromolecules (CERM)
http://hdl.handle.net/2268/226690
10.1007/s10971-018-4751-6

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