Investigation on the formation of self-assembled CdSe dendrite structures and their photocatalytic efficiency

The rapid growth in science and technology has indeed contributed for the modernization, urbanization and the rising of the economic status of the society causing at the same time the adverse effects that pollute nature and its environment. Photocatalysis is one of the favorable techniques which in some way can tackle this problem faced by modern society. The pollution caused owing to the development of industries can be reduced by detoxifying the pollutants in water resources using semiconductor nanomaterials as they swiftly produce radicals that can degrade the pollutants with high reactivity. This present work discusses the synthesis of CdSe nano structures via hydrothermal method and their effects on the reaction time and temperature on the properties of the CdSe nanostructures were investigated by subjecting them to various characterization studies such as X-ray diffraction (XRD), transmission electron microscopy (TEM), ultra violet visible (UV–vis) absorption spectroscopy and fourier transform infra-red spectroscopy (FTIR) and their results were elucidated based on the structural, morphological, optical, and vibrational properties of the synthesized particles. The effect of reaction time on the synthesized CdSe nanostructures showed that the crystallite size increases with increase in reaction time and its size ranges from 9 nm to 35 nm. Similarly, the effect of reaction temperature on the synthesized CdSe nanostructures displayed its size ranging from 15 nm to 35 nm with increase in the crystallite size with respect to the raise in the reaction temperature. The TEM images which exhibit the morphological structure of the samples exposed agglomeration of rod-like structure with respect to the variation in reaction time and temperature and more specifically CdSe nano dendrite structure was formed at a temperature 180 °C with systematic crystallization and strong anisotropy. The investigation of the optical properties of the CdSe samples at all conditions showed a shift towards blue region indicating its special characteristics of fitting into nanosized particles. The bandgap energy obtained from Tauc's plot was ranging from 1.93 eV to 2.11 eV confirming that the decrease in particles size favored increase in bandgap energy. Based on the morphology and on the investigation of the structural and optical properties of the synthesized samples, the obtained dendrite CdSe nanostructures were explored for the photocatalytic study and 85 % of photodegradation efficiency was attained at the end of 180 min and thus proving to be one of the good photocatalyst.