Abstract
Background: Among Advanced oxidation processes, heterogeneous photocatalysis have a great interest, because it uses only light has a source of energy. One of the main limiting processes in photocatalysis is the high probability of electron-hole pair’s recombination in the volume or at the surface of the photocatalyst particles. TiO2 nanotubes grown by anodic synthesis are widely studied because of the large number of potential practical applications especially in photocatalytic or photoelectrochemical applications. However, the preparation of these electrodes at large scale is still challenging due to some technological obstacles such as the electrochemical cell design or the precise control of nanotubes morphology, especially regarding electrolyte ageing and overheating during the synthesis.
Objectives: This study examines the electrochemical synthesis of TiO2 nanotubes supported on large titanium electrodes.
Methods and Results: By understanding heat dissipation phenomenon during the synthesis, an optimized electrochemical cell was designed to prepare 6x4 cm 2 anodes. Then we aimed to control precisely the length of the nanotubes independently of electrolyte ageing. Indeed, It was previously observed that the electrolyte composition evolves (ageing) during the nanotubes synthesis and hence leads to nonreproducible nanotubes morphologies under time-controlled potentiostatic anodization conditions.
Conclusion and Perspectives: To overcome this issue, we developed a Coulometric approach that allows to synthesize, reusing the same electrolyte, several electrodes with a great precision and reproducibility on the length of the nanotubes (2,7 μm ± 160 nm) despite electrolyte ageing. Subsequently, these electrodes can be integrated in a photocatalytic or photoelectrocatalytic process in a real wastewater treatment sector would be very relevant.
Keywords: TiO2 nanotubes, upscaling, electrolyte aging, ph, anodization, coulometric.
Graphical Abstract
[http://dx.doi.org/10.1021/jp953720e]
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