Photocatalytic and radiocatalytic nanomaterials for the degradation of organicspecies

Photocatalytic degradation of environmental organic pollutants using semiconductor nanoparticles, catalyzed by UV and gamma radiation has been well-documented. Several semiconductor materials such as TiO2, ZrO2, Al2O3, and doped semiconductors display photocatalytic activity, although TiO2 has been studied to the largest extent. Here results are presented on TiO2-metal oxide composite photocatalytic nanoparticles and their activities are compared against TiO2 nanoparticles. The composite photocatalytic nanoparticles were synthesized using scalable methodologies. The particle size, morphology, and crystal structure for each particle type were determined by Transmission Electron Microscopy and X-Ray Powder Diffraction. The photocatalytic activities of the unannealed and annealed composite materials were compared with standard TiO2 nanoparticles by examining the rate of sulforhodamine degradation under ultraviolet irradiation in aqueous environments. Enhanced photodegradation of the dye was observed for several of the materials explored. Possible mechanisms explaining the enhanced photocatalytic activity are presented. The most promising photocatalytic materials were then employed as radiocatalysts in the decomposition of sulforhodamine under gamma radiation exposure from a Co-60 source.