Preparation of a Novel TiO₂-Based p−n Junction Nanotube Photocatalyst

Abstract

TiO2 nanotube semiconductors contain free spaces in their interior that can be filled with active materials such as chemical compounds, enzymes, and noble metals, giving them a fundamental advantage over colloids. Although the unique shape of semiconductor nanotubes makes them promising for a range of potential applications, significant developmental research is required. In this research, a novel TiO2 nanotube photocatalyst was prepared that has a p-n junction. The photocatalyst particle surface is physically divided into reduction and oxidation surfaces, which poses a potential driving force for the transport of photogenerated charge carriers. The structure of this nanotube catalyst was characterized using a scanning electron microscope (SEM) and X-ray diffraction (XRD). The catalyst activity was evaluated by coating the catalyst on HEPA filters and determining the destruction rate of toluene in air. The p-n junction nanotube catalyst was shown to have a much higher photocatalytic destruction rate than that of commercially available, nonnanotube structured material, and a higher destruction rate for nanotube catalysts that did not contain a p-n junction.

Iron and chromium doped titanium dioxide nanotubes for the degradation of environmental and industrial pollutants

“…Among these nanostructures, the titanium dioxide nanotubalar materials are of high interest due to chemical inertness, strong oxidizing power, large surface area, non toxicity, high photocatalytic activitry, high cation exchange capacity, strong oxidizer, low cost of production and relatively good stability at elevated temperatures (Khan et al, 2006;Samarghandi et al, 2007;Liang and Li, 2009). This material extensively explored as a catalyst for water splitting and for the production of solar hydrogen (Chen et al, 2005). As a catalyst for the conversion of green house gases into energy producing products for methane and methanol (Chen et al, 2005;Khan et al, 2006).…”

“…This material extensively explored as a catalyst for water splitting and for the production of solar hydrogen (Chen et al, 2005). As a catalyst for the conversion of green house gases into energy producing products for methane and methanol (Chen et al, 2005;Khan et al, 2006). Moreover these nanotubes are widely exploited in lithium ions batteries, electrochemical devices, gas sensors, photoluminescence ion exchange and in photovoltaic dye sensitized solar cells (Kuang et al, 2008).…”

Photoelectrocatalytic degradation of organic contaminants at Bi2O3/TiO2 nanotube array electrode

“…Such an infrastructure is especially favorable for mass diffusion. Therefore, TiO 2 nanotube arrays show great potential for practical environmental purification [2,3].…”

“…One of the approaches is coupling TiO 2 with other semiconductor with appropriate band gaps. A large number of coupled polycrystalline or colloidal semiconductor, in which the particles adhere to each other in so-called sandwich structures or present a core-shell geometry, have been prepared such as SiO 2 [4][5][6][7] were reported to be efficient under visible light irradiation. However, the photocatalytic mechanism for the coupled system has not been systematically investigated, and no clear evidence was provided for the complete decomposition of organic pollutants under visible light.…”

Effects of structure of anodic TiO2 nanotube arrays on photocatalytic activity for the degradation of 2,3-dichlorophenol in aqueous solution

“…Many researches have proven that multidimensional TiO 2 has the higher photochemical reactivity than that of bulk TiO 2 particles [5][6][7]. Advances in the nanoscale technology facilitated the synthesis of highly-ordered and multidimensional structured materials.…”