Visible light facilitated degradation of alternate dye solutions by highly reusable Mn-ZnO nano-photocatalyst

Keeping the industrial viability in view, manganese incorporated zinc oxide nanocomposites (Mn-ZnO NCs) was synthesized as a reusable photocatalyst. The photocatalytic efficiency of Mn-ZnO NCs was compared with ZnO nanoparticles. Morphology and size of the samples were modulated using sodium dodecyl sulphate (SDS) as the cappant. The crystallite size and crystalline parameters were estimated through X-ray diffraction spectra, while the adsorption of SDS on the samples was assessed through Fourier transform infrared spectra. Since the efficiency of any photocatalyst fundamentally depends upon its photo-physical and surface properties, UV-Visible, Photoluminescence, and Electron paramagnetic resonance spectroscopic techniques were used to access the optical properties while Field emission scanning electron microscopy was employed to deduce the morphology of the samples. Energy dispersive X-ray spectra and X-ray photoelectron spectra confirmed the elemental composition of the samples. The photocatalytic degradation of dye solutions was monitored initially through UV-Vis spectra. In order to confirm that the final products of photocatalytic degradation were non-toxic, Mass spectrometry was employed to estimate the types of intermediates and final products formed during and after the course of photocatalytic reaction. The results of visible light assisted photocatalytic degradation studies indicated that Mn-ZnO NCs were highly reusable for degrading alternate solutions of dyes (rhodamine B and methylene blue) as well as their mixture within a span of only 20 min. The difference in the morphology of Mn-ZnO NCs before and after performing the photocatalytic activity was also assessed.