Highly Ordered TiO₂ Nanotube Arrays with Controllable Length for Photoelectrocatalytic Degradation of Phenol

Abstract

Highly ordered TiO2 nanotube array prepared by a potentiostatic anodization shows a considerable potential for improving the transport of the photogenerated electrons in the TiO2 film, since the ordered architecture can provide a unidirectional electric channel and reduce the grain boundaries. Here, we report on the application of highly ordered TiO2 nanotube arrays with different lengths for the photoelectrocatalytic degradation of phenol. The lengths of the nanotube arrays can be controlled by the electrolyte media, anodization time, or both. The photoelectrocatalytic activity shows a dependence on the length of the nanotube arrays. Under 3.1 mW/cm2 irradiance of ultraviolet light, a short nanotube array shows better photoelectrocatalytic activity than a long nanotube array, which can be explained by the reduced recombination effects. When compared with a P25 TiO2 particulate film with similar thickness and geometric area, the nanotube array shows a stronger attachment to the parent titanium substrate and a better photoelectrocatalytic activity for phenol degradation owing to the improved electron transport and reduced charge recombination. This superior electron transport is further supported by the remarkably enhanced anodic photocurrent response in the degradation of phenol.

Evolution of TiO2 Nanotubular Morphology Obtained in Ethylene Glycol/Glycerol Mixture and its Photoelectrochemical Performance

“…The Ti foil was used as the working electrode and a platinum foil as the counter electrode. The distance between these electrodes was about 2 cm 27 . The anodization was performed at 60 V at a potential ramp of 1 V s -1 , in organic electrolyte consisting a mixture of glycerol (Synth 99.5%) and ethylene glycol …”

“…By controlling parameters such as anodization potential [24][25][26] anodization time 27,28 , temperature 22,29 , as well as the electrolyte composition 30 and its pH value 31 , different nanotubular structures can be obtained. The first and second generations of electrolytes were based on aqueous electrolytes containing hydrofluoric acid and fluoride salts, respectively 32,33 .…”

Controlled Synthesis of TiO2 Hierarchical Nanofibre Structures via Electrospinning and Solvothermal Processes: Photocatalytic Activity for Degradation of Methylene Blue

“…The reaction rate for photocatalytic reactions is independent of hydroxyl concentration 33 , therefore, a pseudo first-order kinetic model was used to fit the experimental data:…”

Controllable Synthesis of ZnO Nanorod-nanosheets Hierarchical Nanostructure on a Stainless Steel Mesh Via A Facile Hydrothermal Growth

“…Dye removal by photoinduced decomposition of pollutants on photocatalysts has been widely researched [10] . ZnO is also considered as an effective photocatalyst for degrading contaminants [11].…”