Fabrication of cationic microgels doped MnO2/Fe3O4 nanocomposites, and study of their photocatalytic performance and reusability in organic transformations

Abstract

AbstractThis article reports, the fabrication of cationic microgel doped MnO2/Fe3O4 nanocomposites (CM@MnO2/Fe3O4) via free radical emulsion polymerization technique, and an economical and environmental friendly approach to some organic transformations, such as heterogeneous photocatalytic reduction of methylene blue (MB, toxic dye), para‐nitro phenol (PNP, harmful pollutant) and dimethyl amino benzaldehyde (DMAB, skin allergic reagent) in presence of UV light (38 W). First of all, three different crosslinked grades of cationic microgels (CMs) have been synthesized by using styrene, dimethyl acrylamide, cyclohexyl methacrylate, [2‐(acryloyloxy)ethyl] trimethylammonium chloride and N‐hydroxymethyl acrylamide monomers by taking different amounts of N‐hydroxymethyl acrylamide, and keeping the other monomers in fixed quantities. Further, all the grades of CMs have been doped by bimetallic MnO2/Fe3O4 nanoparticles, through hydrothermal method. Fabrication of CMs and CM@MnO2/Fe3O4 nanocomposites has been confirmed by the characteristic peaks observed in FT‐IR spectral analysis and their thermal stability has been evidenced by thermogravimetric analysis. TEM and DLS analyses have revealed their particular size. The surface morphology of CMs and CM@MnO2/Fe3O4 nanocomposites has been visualized by scanning electrode microscope analysis. The nanocomposites have effectively and efficiently catalyzed the reduction reactions of MB, PNP, and DMAB, in presence of UV light, by 98%, 98%, and 86%, respectively. The photocatalysts have been reused up to eight cycles without any loss of their catalytic activity. The photocatalytic reductions have also been studied for their kinetics, and exhibited pseudo first order kinetics (kapp, 10−2 min−1).