Sol-gel synthesize and characterization of χGd 2 Ti 2 O 7 /SiO 2 photocatalyst for ofloxacin decomposition

Abstract Gd 2 Ti 2 O 7 was loaded on the surface of quartz spheres by a sol-gel method. The Gd 2 Ti 2 O 7 maintains the pyrochlore phase after loading. Dispersion of Gd 2 Ti 2 O 7 on the SiO 2 spheres reduces crystallite size of Gd 2 Ti 2 O 7 . The surface of SiO 2 sphere is coated with a rough layer of Gd 2 Ti 2 O 7 . The band gap energy of the χGd 2 Ti 2 O 7 /SiO 2 constantly increases with decreasing Gd 2 Ti 2 O 7 loading content, ranging from 3.35 eV to 3.71 eV. The porous structure in the χGd 2 Ti 2 O 7 /SiO 2 composite mainly comes from the Gd 2 Ti 2 O 7 layer. The maximum BET surface area and total pore volume are even larger than that of the unloaded Gd 2 Ti 2 O 7 . The hydroxyl radical generation efficiency during illumination is enhanced after loading Gd 2 Ti 2 O 7 on SiO 2 . The 30%Gd 2 Ti 2 O 7 /SiO 2 sample has the optimal photocatalytic activity. 65.6% of the initial ofloxacin can be decomposed on 30%Gd 2 Ti 2 O 7 /SiO 2 after 30 min of UV light irradiation, as compared to 24.1% on the unloaded Gd 2 Ti 2 O 7 .