Synthesis, Characterization, and Photocatalytic Activity of Pure and N-, B-, or Ag- Doped TiO2

Paula Bezerra,Amilcar Machulek Jr,Aline Garcia,Rodrigo Cavalcante,Pilar Marco,Heberton Wender,Silvio Oliveira,Jaime Giménez,Gleison Casagrande,Marco Martines

doi:10.21577/0103-5053.20170040

Abstract

This article reports the synthesis and characterization of pure and N-, B-, and Ag-doped TiO2 and the ability of these oxides to photodegrade methylene blue (MB) under sunlight or UV-ABC radiation. The compounds were synthesized using the sol-gel method and characterized by scanning electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Photocatalytic efficiency was significantly increased by N-doping, resulting in 98% MB decomposition under UV-ABC irradiation for 180 min. Ag- and B-doped TiO2 lowered MB degradation rates to 52 and 73%, respectively, compared with pure TiO2. The same behavior was observed with exposure to UV-Vis, with 88, 65, 60, and 42% MB removal with N-doped, pure, B-doped, and Ag-doped TiO2, respectively. Under visible light alone, N-doped TiO2 exhibited higher photocatalytic efficiency than commercial P25-type TiO2. Photocatalysis with N-doped TiO2 proved to be a promising alternative for MB degradation, given the potential of employing solar energy, thus minimizing operating costs.

Highlights

Incomplete removal of organic compounds in conventional wastewater treatment plants (WWTPs) has been identified as one of the principal routes whereby anthropogenic pollutants can reach aqueous environments.[1]
The versatility of advanced oxidation processes (AOPs) stems from the availability of several routes for HO production, imparting high adaptability to environmental recovery approaches,[2,6] including methods based on UV, H2O2/UV, O3/UV, and H2O2/O3/UV, which rely on UV-C photolysis of H2O2, ozone, or both to produce active species
UV‐Vis irradiation is employed in methods such as photoFenton, in which H2O2 is added to dissolved iron salts and heterogeneous photocatalysis, while a powder or a supported semiconductor is used as the active material.[2]

Summary

Introduction

Incomplete removal of organic compounds in conventional wastewater treatment plants (WWTPs) has been identified as one of the principal routes whereby anthropogenic pollutants can reach aqueous environments.[1]. In experiments conducted by Liang et al.,[33] B-doped TiO2 exhibited high photocatalytic efficiency, attributed to decreased bandgap energy, during rhodamine B degradation under simulated sunlight.

Results

Conclusion