Fabrication of photocatalyst based on Eu³⁺-doped ZnS-SiO₂ and sodium alginate core shell nanocomposite

This research paper reports the photocatalytic properties of Zn-SiO₂-Eu³⁺ and sodium alginate (Alg) based nanocomposites for the degradation of indigo carmine dye. Initially, Eu³⁺ doped ZnS-SiO₂ nanophorphor was synthesized and after that it was incorporated within the grafted crosslinked polymer matrix of Alg with acrylamide-co-acrylic acid in different concentrations. Synthesized materials were characterized using XRD, Raman spectroscopy, FTIR, SEM/EDX, TEM and UV-vis diffuse reflectance spectroscopy. XRD and TEM analyses confirmed the formation of nanoparticles as well as the uniform distribution of the nanoparticles within the polymer matrix. The UV-vis and UV-vis DRS spectral analysis indicated that Eu³⁺ doping causes a red-shift in the absorption band, resulting in the reduction in band gaps. The synergic effect of ZnS and Eu³⁺ in the SiO₂ evidenced the photocatalytic performance of the catalyst. Alg-cl-poly(AAM-co-MAA)/ZnS-SiO₂-Eu³⁺ nanocomposites were found to be very effective for the degradation of indigo carmine under visible light. Highest photocatalytic performance (93.4%) was shown by the nanocomposite with the 20% concentration of the nanoparticle after 5h. The photocatalytic activity was mainly attributed to the intense light absorption in the visible region and narrow band gap energy.