Synthesis of CdSe QDs decorated ZIF-8 composite for visible light assisted degradation of methylene blue

Abstract

Metal organic frameworks have proven to be a crucial facet for the enhancement of environmental research because of their excellent properties, especially, extensive surface area. In the present study, we propose the synthesis route of CdSe quantum dots (CdSe QDs) and zinc imidazole framework-8 (ZIF-8) composite for the effective and potential methylene blue (MB) degradation via photocatalysis in visible range which is kinetically a pseudo first-order reaction. ZIF-8 itself is a photocatalyst but it has large band gap (4.8–5.1 eV) in ultraviolet region. The doping of CdSe QDs into the ZIF-8 matrix is done with the aim of deviating the photocatalytic activity to visible range by lowering of the band gap of ZIF-8 which was validated by UV–vis–DRS. XRD results indicated the decrease in the d-spacing, crystallite size and also provided the information about the positive microstrain for all the components. FTIR and Raman spectra confirmed the composite synthesis and the CdSe longitudinal (LO) and surface optical phonon modes (SO) along with the fundamental modes of ZIF-8, respectively. The elemental state of the constituent was established by XPS analysis. The adsorption isotherm data and the kinetic studies indicate that the CdSe-ZIF-8 composite has a great potential as a catalyst.