Sonochemical Synthesis of Ce-doped TiO2 Nanostructure: A Visible-Light-Driven Photocatalyst for Degradation of Toluene and O-Xylene.

Lee Lee,Choi Choi

doi:10.3390/ma12081265

Abstract

Ce-doped TiO2 nanostructures (CeT) with different amounts of Ce (0.5, 0.75, 1.0, 1.5, and 2.0 wt. %) were synthesized using a sonochemical processing method. The physicochemical properties of the prepared samples were explored using UV-visible diffuse reflectance spectroscopy (UV-vis DRS), field-emission TEM (FE-TEM), XRD, X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL), and surface area and pore size analyzers. The photocatalytic performance of the prepared CeT was assessed by monitoring their degradation efficiencies for gaseous toluene and o-xylene—widely known as significant indoor air pollutants—under daylight irradiation. The prepared CeT exhibited significantly improved photocatalytic performance towards the degradation of toluene and o-xylene, which was much higher than that observed for pure TiO2 and commercial P25 TiO2. Particularly, photocatalytic degradation efficiencies by the prepared CeT catalysts increased remarkably in the case of o-xylene (up to 99.4%) compared to toluene (up to 49.1%). The degradation efficiency by the CeT was greatest for the CeT-0.75 sample, followed by, in order, CeT-1.0, CeT-0.5, CeT-1.5, and CeT-2.0 samples in agreement with the order of the surface area and the particle size of the catalysts. According to the change of light source, the average decomposition efficiencies for toluene and o-xylene by CeT-0.75 were shown in the order of conventional daylight lamp > violet light emitting diodes (LEDs) > white LEDs. The decomposition efficiencies normalized to supplied electric power, however, were estimated to be in the following order of violet LEDs > white LEDs > conventional daylight lamp, indicating that the LEDs could be a much more energy efficient light source for the photodecomposition of target toluene and o-xylene using the CeT-0.75 photocatalyst.

Highlights

Aromatic volatile compounds are considered to be serious indoor air pollutants because they can cause adverse health risks for building occupants [1]
It has been reported that the central nervous system (CNS) is likely to be damaged by the exposure to toluene and xylene [3]
All the photocatalysts used in this study revealed anatase, rutile, and brookite phase structures, and anatase phase peak was exhibited as the main structure with a main peak at 2θ = 25.3◦

Summary

Introduction

Aromatic volatile compounds are considered to be serious indoor air pollutants because they can cause adverse health risks for building occupants [1]. The appearance of these compounds indoors results mainly from the wide use of them as building interior materials, household products, and so on [1]. Exposure to low to moderate levels of toluene vapor can cause dizziness, nausea, confusion, memory loss, weakness, loss of appetite, hearing, and color vision loss. Long-term exposure to toluene vapors may lead to damage of the central nervous, the reproductive, and the immune systems, and can even cause death [3,4]

Methods

Results

Conclusion