High aspect ZnO nanorod growth over electrodeposited tubes for photocatalytic degradation of EtBr dye.

In this work, vertically grown rod type ZnO nanostructures have been synthesized on metallic nickel tube films fabricated through the cost-effective process of electroforming. The use of tubular metal substrates for the growth of ZnO nanorods has been found to be advantageous for the photocatalytic degradation of EtBr dye because of their high surface area-to-volume ratio. The nickel tubes with ZnO nanorods were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The developed system was utilized for the photocatalytic degradation of EtBr dye and its efficacy was revealed through the comprehensive mineralization of the dye within 150 min. The mechanism of the degradation process has been revealed through total organic carbon (TOC), chemical oxygen demand (COD) and high-performance liquid chromatography (HPLC) studies. A substantially lower amount of the photocatalyst has been used because of the homogeneously distributed growth of nanorods on the substrate. Density functional theory-based analysis has also been performed to study the photocatalytic degradation and adsorption properties of EtBr on ZnO nanorods. Using first principles DFT theory, geometry optimizations and vibrational analysis are performed which show a negative charge transfer from the substrate to the photocatalyst. For the first time this article reports the use of DFT analysis for investigating the adsorption of EtBr on ZnO nanorods, and the experimental growth of nanorods over electroformed Ni tubes.