ZnO-ZnSe Common Cation Heterostructures: In Situ Synthesis, Characterization and Photocatalytic Activity

Abstract

Environmental remediation using sunlight is one of the most promising and cost-effective approaches to mitigate environmental hazards significantly related to the industrial development. In the present work, we reported the synthesis of the common cation ZnO/ZnSe heterostructures via one-pot hydrothermal method at 200 ºC temperature for 3 hours. The as-synthesized photocatalysts were employed for the photocatalytic degradation of di-azo dye i.e. Congo red. XRD spectroscopy was used to analyze the crystal structure, purity and phase of the common cation ZnO/ZnSe heterostructured photocatalysts. Moreover, crystallite sizes and cell volumes of synthesized photocatalysts were also calculated using XRD data. Morphological analysis was carried out via SEM and TEM. The elemental composition in the synthesized photocatalysts was also confirmed using EDX spectroscopy. The alignment of energy levels is an important parameter to determine the pathway of photocatalytic reactions and it was determined with the help of UV-visible spectroscopy as well as XPS analysis from the literature to find the valence band position. Finally, the as-synthesized heterostructures were used for the photocatalytic degradation of Congo red dye under UV-visible irradiation. However, maximum degradation efficiency of 91% in 40 minutes was observed in case of ZnO/ZnSe photocatalysts with 75% ZnSe, respectively. The higher photocatalytic degradation efficiency was attributed to the efficient charge separation as well as the presence of common cation in ZnO/ZnSe heterostructures.