Photosensitising reactive oxygen species with titanium dioxide nanoparticles decorated with PbS quantum dots

The development of new efficient photocatalysts based on nanostructured materials with a wide range of photosensitivity in visible and near-infra-red regions and high efficiency of reactive oxygen species generation is an important task. The purpose of this project was to establish the possibility of photosensitising the process of generating reactive oxygen species (ROSs) with TiO2 nanoparticles (NPs) decorated with colloidal PbS quantum dots (QDs) passivated with 3-mercaptopropionic acid (3MPA) as well as the possibility of increasing the spectral sensitivity of synthesised nanoheterosystems into the red region. The paper analyses the photocatalytic properties of TiO2 NPs with an anatase structure and average size of 12 nm decorated with colloidal PbS QDs with an average size of 2.7 nm passivated with 3MPA. It also provides structural and spectral substantiation of the formation of TiO2 NPs – PbS/3MPA QDs nanoheterostructures. Absorption and luminescence techniques were used to establish the efficiency of generating various ROSs by TiO2 NPs – PbS/3MPA nanoheterostructures and their individual components under excitation in the UV and visible radiation. It was shown that TiO2 NPs decoration with PbS QDs extends the spectral range of sensitivity to the generation of reactive oxygen species in the UV to 1,100 nm. The study revealed an increased efficiency of hydrogen peroxide generation by nanoheterostructures as compared to individual PbS QDs and TiO2 nanoparticles.