tailieunhanh - Synthesis and characterization of anatase TiO2:Cu2+ powders prepared via a sol-gel technique

The XRD analysis showed that the doped samples exhibit anatase single phase at annealing temperature 600 oC. The Cu2+ contents did not affect the lattice of TiO2 host, but affected positions of its Raman modes. The band gap of the TiO2:Cu2+ decreases with the increase of doping concentration. | VNU Journal of Science: Mathematics – Physics, Vol. 34, No. 3 (2018) 22-27 Synthesis and Characterization of Anatase TiO2:Cu2+ Powders Prepared via a Sol-gel Technique Trinh Thi Loan*, Nguyen Ngoc Long Faculty of Physics, Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi Received 22 May 2018 Revised 23 July 2018; Accepted 01 August 2018 Abstract: Anatase TiO2 powders doped with different amounts of Cu 2+ ions (0, , and mol%) were successfully synthesized by sol-gel method from precursors of TiCl4, (CH3COO)2Cu. Effect of Cu2+ concentrations on the structural and optical properties of TiO2 host was investigated by X-ray diffraction, Raman spectroscopy and diffuse reflection spectroscopy. The XRD analysis showed that the doped samples exhibit anatase single phase at annealing temperature 600 oC. The Cu2+ contents did not affect the lattice of TiO2 host, but affected positions of its Raman modes. The band gap of the TiO2:Cu2+ decreases with the increase of doping concentration. Keywords: TiO2:Cu2+ powders, sol-gel, structure, Raman scattering, band gap energy. 1. Introduction In recent years, the titanium dioxide, also known as titania (TiO2), has received great attention by a lot of researchers around the world because of its potential applications, such as gas sensing [1, 2], solar cells [3], self-sterilising coatings [4], water treatment [5] and photocatalysis [6]. However, the anatase phase has a large band gap (~ eV), hence the photocatalytic degradation process occurs only under ultraviolet light (less than 5 % of the solar spectrum). In the past few years, some works have been devoted to the reducing TiO2 band gap by doping TiO2 with transition metal ions. By this way, the optical response of TiO2 under visible light irradiation can improve [7]. The impurity doping induces substantial modifications in electronic structure, chemical composition and optical properties of semiconducting materials. There are many methods for synthesis