Facile Fabrication of MgAl2O4/MWCNT nanocomposite for efficient and stable solar-driven degradation of organic dye

This work reports the synthesis and characterization of Magnesium Aluminate (MgAl 2 O 4 ) and Magnesium Aluminate/Multi Walled Carbon Nanotube (MgAl 2 O 4 /MWCNT) nanocomposite by facile chemical co-precipitation method for the dye degradation application. MgAl 2 O 4 and MgAl 2 O 4 /MWCNT nanocomposite are characterized by Scanning Electron Microscopy (SEM), x-ray Diffractometry (XRD), Raman Spectrometry, UV–vis Spectrophotometry (UV–vis), Fourier Transform Infrared Spectroscopy(FTIR), and x-ray Photoelectron Spectroscopy (XPS). Surface morphology of MgAl 2 O 4 /MWCNT nanocomposite exhibits entangled needle-like structures while MgAl 2 O 4 spinel comprises agglomerated nanoparticles of different sizes. XRD confirms the formation of MgAl 2 O 4. XPS identifies the chemical states and binding energies of constituent elements present in the sample. Optical properties reveal that addition of MWCNTs in MgAl 2 O 4 decreases the optical bandgap energy from 3.02 eV to 2.78 eV. MgAl 2 O 4 /MWCNT nanocomposite shows reduced bandgap compared to pristine MgAl 2 O 4 due to increased chemical defects or vacancies in intergranular regions and chemical interaction between MgAl 2 O 4 and MWCNT, leading to the formation of new energy levels in MgAl 2 O 4 /MWCNT nanocomposite. Addition of MWCNTs provides a large surface area, more active sites, and enhances electron mobility between energy levels. MgAl 2 O 4 /MWCNT nanocomposite proves itself a better photocatalyst due to the fast degradation of Methyl Blue (MB) in 65 min as compared to MgAl 2 O 4 which degrades the dye in 90 min. MgAl 2 O 4 /MWCNT nanocomposite also shows good stability and reusability even after performing the six cycles of dye degradation.