Photocatalytic performance of the titanium dioxide modified with zirconium silicate obtained by sol-gel method

Full text: Titanium dioxide semiconductor is widely investigated for photocatalysts materials and the anatase phase amount has been described as an important factor for high performance. However, the structural origin for photonic behaviour emerges to crystallographic changes what affects the time of electron-hole recombination. High temperature of thermal treatment can be reduce the structural defects on the anatase phase, but an irreversible phase transition to rutile phase start to occurs. While the anatase phase possesses ABO₄ ordering, the rutile structure present AO₂ one [1]. The insertion of dopants that stabilizes the ABO₄ structure can improve the photocatalytic performance of that material [2,3]. In this work, the effect of zirconium silicate at 5 mol% was studied on the view point of anatase stabilization of the titanium dioxide. The powder samples were synthesized by Sol-Gel method and calcined from 550 to 700 deg C for 2 hours in static atmosphere. Structural and photonic characteristic were characterized by XRD and diffuse reflectance spectroscopy, respectively. The structural parameters were determined by Rietveld Method and correlated to the Band gap values obtained form linear regression at the uptake absorption. Anatase single phase was obtained for all of the samples. The anatase structure is stressed significantly around 600 deg C, presenting anomalous lattice parameters, but the rutile conversion does not occur. Band gap values showed to be associated to the lattice structure. All of the samples were tested for degradation of Rhodamine B dye solution and all of the samples presented high degradation until 2 hours of UV light irradiation. References: [1] JCPDS - Powder Diffraction File, Pennsylvania, 2003. [2] BALACHADARAN, K. VENCKATESH, R. SIVARAJ, R. Intern. J. Engin. Sci.e & Techn. Vol. 2(8), 2010, 3695-3700. [3] CAVALHEIRO, A, BRUNO, J, SAEKI, M, VALENTE, J, FLORENTINO, A. J. Mater. Sci. v. 43, n.2, p. 602-608, 2008. (author)