Tunable optical properties of Au nanoparticles encapsulated TiO2 spheres and their improved sunlight mediated photocatalytic activity

Abstract

Plasmonic nanoparticles mediated improved light absorption and enhancement in the charge carrier lifetime of the semiconductor provides a tremendous contribution in the field of advanced photocatalysis. We report the synthesis of Au nanoparticles encapsulated TiO2 nanospheres with tunable optical properties using the variation in the size of Au nanoparticles. Microscopy studies manifest the morphological changes and average size modulation from 42 to 297 nm with the variation in the size of Au nanoparticles. HRTEM, Elemental mapping, Raman and XRD studies assure the formation of anatase TiO2 spheres contained Au nanoparticles. UV-DRS studies indicate the modulation in the bandgap and optical absorption with the particle size variation of Au nanoparticles. Photoluminescence results indicate the reduction in the recombination rate with the increment in the size of Au nanoparticles. Au nanoparticles contained TiO2 spheres were employed for the sunlight-induced breakdown of MB, MG and MO molecules in water. Most efficient Au-TiO2 nanohybrids decompose the 20 μM MB, 10 μM MG and 10 μM MO molecule solution in 30, 20 and 10 min, respectively. The outstanding photodegradation ability of Au-TiO2 nanohybrids spheres can be attributed to the creation of the Schottky interface between Au and TiO2 nanoparticles and their improved visible light-harvesting ability.