Synthesis and Characterization of a Nano‐Composite CuO@Zn−2‐PTZ {Zn−2‐PTZ=bis[5‐(2‐pyridyltetrazolato)]diaquazinc(II)} for Efficient Photo‐catalytic Degradation of Methylene Blue (MB), Methyl Orange (MO) and mixed(MB‐MO)Dyes in Sunlight

Abstract

AbstractRemoval of organic contaminants such as azo dyes is highly desirable from the industrial waste waters because of their toxicity, stability, and mutagenic properties. Herein, the nano‐composite CuO@Zn−2‐PTZ has been synthesized by a simple hydrothermal method and characterized by a combination of techniques like Powder X‐Ray Diffraction (PXRD), UV‐Visible spectroscopy, Fourier Transform Infrared (FT‐IR) spectroscopy, Scanning Electron Microscopy‐Energy Dispersive X‐ray analysis (SEM‐EDX) etc. The band gap of the composite was found to be 2.07 eV, indicating the spread of absorption in to the visible region in comparison to the high (3.76 eV) band gap of the parent metal organic framework (MOF) Zn−2‐PTZ. The composite CuO@Zn−2‐PTZ exhibited much higher photo degradations, under natural sunlight, towards the decompositions of the cationic [Methylene Blue (MB)] and anionic [Methyl Orange (MO)] dyes as well as mixed MB and MO dyes taken in water. A comparative study was also undertaken by taking CuO nanoparticles and the parent MOF separately with the same set of dyes under same conditions to substantiate the above. The enhancement of photo‐catalytic activity has been caused by the formation of a p‐n hetero‐junction in the composite. The Langmuir‐Hinshelwood model showed that the degradation rates of the dyes follow pseudo‐first‐order kinetics.