Photoeletrocatalytic Activity of a Cu₂O-Loaded Self-Organized Highly Oriented TiO₂ Nanotube Array Electrode for 4-Chlorophenol Degradation

Abstract

Differently sized Cu2O nanoparticles have been assembled photocatalytically on the surface of self-organized highly oriented TiO2 nanotubes obtained by anodization of a Ti sheet in fluoride-containing electrolytes. X-ray diffraction analysis identifies an anatase structure and fine preferential orientation of (101) planes. The UV-vis absorption edge of the TiO2 nanotube arrays shift to lower energy after Cu2O loading. The composite array electrode exhibits a higher photovoltage response than the TiO2 powders directly deposited on a Ti sheet. The highest photoconversion efficiencies observed for the Cu2O-loaded electrode are 17.2% and 0.82% under UV light and visible light irradiation, respectively. Especially, the composite array electrode shows a higher efficiency than the nonloaded one for the photoelectrocatalytic decomposition of 4-chlorophenol. The improved photoeletrocatalytic activity of the TiO2/Cu2O composite array electrode is attributed to the synergistic effect of Cu2O nanoparticles and TiO2 nanotube arrays. The Cu2O nanoparticles could enhance the efficiency of photon harvesting and reduce the chances of electron-hole recombination by sending the electrons to the conduction band of TiO2 nanotubes. The accumulated electrons in the conduction band of TiO2 nanotubes would reduce oxygen to form peroxides for enhanced advanced oxidation. The byproducts were identified by high-performance liquid chromatography.

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Photon Absorption Enhancement of TiO2 Nanotube Arrays Decorated with Aluminum Nanoparticles

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Fabrication of mixed-crystalline-phase spindle-like TiO2 for enhanced photocatalytic hydrogen production

“…Therefore, the SPV spectra of the samples were measured to understand the heterojunction effect. SPV spectroscopy is a rapid and non-destructive measurement technique for obtaining information about the separation rate of photoinduced charge carriers, and is based on the differences in the SPV before and after the sample is irradiated [28]. Fig.…”