tailieunhanh - Synthesis of Ag-TiO2 nanomaterial for treatment of organic pollutants under visible light

In this study, the sol-gel synthesis method was employed for the preparation of silver-doped TiO2 nanomaterial from potassium fluorotitanate and silver nitrate. The silver can be incorporated by direct calcination of the sol-gel material decomposing silver nitrate to silver. The visible light absorption ability of Ag- TiO2 nanoparticles was investigated by means of UV-Vis measurement. | Vietnam Journal of Chemistry, International Edition, 55(2): 167-171, 2017 DOI: Synthesis of Ag-TiO2 nanomaterial for treatment of organic pollutants under visible light Nguyen Thi Dieu Cam1*, Mai Hung Thanh Tung2 1 Quy Nhon University 2 Ho Chi Minh City University of Food Industry Received 14 September 2016; Accepted for publication 11 April 2017 Abstract In this study, the sol-gel synthesis method was employed for the preparation of silver-doped TiO2 nanomaterial from potassium fluorotitanate and silver nitrate. The silver can be incorporated by direct calcination of the sol-gel material decomposing silver nitrate to silver. The visible light absorption ability of Ag- TiO2 nanoparticles was investigated by means of UV-Vis measurement. Based on the UV-Vis spectra, the absorption in the visible light of the Ag-TiO2 was found to be improved and was shifted to longer wavelength. The XPS spectra indicated that the elements detected were titanium, oxygen, and silver. Titanium and oxygen presented as Ti4+ and O2− and silver Ag existed in Ag (0) form. It is attributed to the fact that the silver is homogeneously dispersed throughout the material. The experimental results showed that the photocatalytic efficiency of Ag-TiO2 was better than prepared TiO2 under the same conditions for the photodegradation of methylene blue. Keywords. Potassium fluorotitanate, titanium dioxide, silver, photocatalysis, visible light. 1. INTRODUCTION In the last decades, TiO2 materials are most extensively studied owing to their stability, nontoxicity, and low cost. However, TiO2 only exhibits photocatalytic activity under UV irradiation, because of its large band gap energy ( eV) and fast recombination rate of photogenerated electron–hole pairs [1-5]. These drawbacks restrict the use of visible light or sunlight as the radiation source for photocatalysis of TiO2. The development of titaniabased photocatalysts activated by visible light remains a great .