Enhanced Photocatalytic Activity of {110}-Faceted TiO2 Rutile Nanorods in the Photodegradation of Hazardous Pharmaceuticals

Tran Huyen,Hendrik Kosslick,Nguyen Dung,Nguyen Liem,Tran Chi

doi:10.3390/nano8050276

Abstract

Rutile TiO2 with highly active facets has attracted much attention owing to its enhanced activity during the photocatalytic degradation of pollutants such as pharmaceuticals in wastewater. However, it is difficult to obtain by controlling the synthetic conditions. This paper reports a simple hydrothermal synthesis of rutile TiO2 nanorods with highly exposed {110} facets. The obtained rutile was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. The main contribution to the photocatalytic activity comes from rutile nanorods with highly dominant active {110} facets, which were studied in the photodegradation of reactive cinnamic acid and more recalcitrant ibuprofen. The contribution of active species was also investigated. The present work further confirmed the hydrothermal synthesis route for controlling the preparation of highly crystalline and active rutile nanocrystals.

Highlights

Heterogeneous photocatalysis on semiconductor photocatalysts has attracted considerable interest due to its applicability in the treatment of hazardous organic pollutants [1,2,3,4,5]
The large-sized rutile nanocrystals with highly exposed {110} facets were successfully prepared by hydrothermal synthesis and exhibited an enhanced activity in the photodegradation of reactive cinnamic acid (CA) and recalcitrant pharmaceutical ibuprofen (IBP)
The X-ray diffraction (XRD) pattern (Figure 1a) revealed that the obtained hydrothermal product was present in the rutile form with a high intense diffraction peak at 27.4◦ (2θ) corresponding to the {110} facets and others with high intensities located at 36.1◦, 41.2◦, and 54.3◦ representing the {101}, {111}, and {211} facets, respectively [16,19]

Summary

Introduction

Heterogeneous photocatalysis on semiconductor photocatalysts has attracted considerable interest due to its applicability in the treatment of hazardous organic pollutants [1,2,3,4,5]. Kalaivani’s group reported the enhanced photocatalytic decolourization efficiency of methylene blue over the bio-nanocomposite inulin-TiO2 rutile under ultraviolet (UV) irradiation [15]. Nair’s group found that the high photocatalytic activity of three-dimensional rutile micro-flowers in the decolourization of Rhodamine B under UV light was due to the large surface area contributed by the highly dense spiky nanostructures [16]. The reported rutile with exposed {111} facets that had both the advantages of large specific surface area and exposed high active facets were active in the decolourization of methylene blue under UV irradiation [19]. The photocatalytic performances were investigated under low power solarium lamps, high organic loading, and a small amount of the photocatalyst Such testing conditions have been rarely reported in wastewater treatment. Trapping experiments were carried out to analyze the contribution of active species to the photodegradation of organic compounds

Methods

Results

Conclusion