Synthesis of highly efficient and magnetically separable Fe3O4@C-TiO2-Ag catalyst for the reduction of organic dyes and 4-nitrophenol

Abstract

The engineering of Nanocatalyst with tunable physiochemical properties is vital for the advancement of the catalytic system. In this article, we synthesized Fe3O4@C-TiO2-Ag spheres with different silver concentrations for methylene blue (MB), methyl orange (MO) and 4-nitrophenol (4-NP) catalytic reduction. The synthesized nanocomposite was analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), energy dispersive X-Ray Analysis (EDX), X-ray photoelectron spectroscopy (XPS), diffused reflectance spectroscopy (DRS), dynamic light scattering (DLS) and vibrating sample magnetometer (VSM), which revealed nanospheres like morphology with a high surface area of 147.05 cm3 g−1 and notable magnetization saturation value (Ms) of 20.3 emu/g. The rate constant (k) values for Fe3O4@C-TiO2 and Fe3O4@C-TiO2-Ag with different Ag concentrations were calculated, among which the highest was 0.38 min−1, 0.22 min−1 and 0.063 s−1 for MB, MO and 4-NP, respectively. The reduction of both dyes and 4-NP follows a first-order reaction. The amount of the catalyst and pH for MB and MO reduction was also investigated. The synthesized nanocatalyst was recycled several times and can be separated easily by using an external magnetic field from the reaction system. These results demonstrate a very efficient, reusable, and cost-effective catalyst in the field of catalysis technology development.