Size-Dependent Magneto-Photocatalytic Properties of Mn-Doped Fe₃O₄ Nanoparticles Dispersed over the KIT-6 Matrix for the Photocatalytic Degradation of p-Chlorophenol

Abstract

The correlation of the particle size with the magnetic property and that of the photocatalytic property has always garnered strong interest. Magnetic nanoparticles (MNPs) of Mn-doped Fe 3 O 4 dispersed in KIT-6 (mesoporous silica) were synthesized by a hydrothermal method, and a facile recipe for dispersion of these MNPs was developed. These materials were characterized with different techniques like small-angle X-ray scattering (SAXS), X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, field emission scanning electron microscopy, etc. The SAXS study shows that KIT-6 possesses a three-dimensional cylindrical pore system, and these pores get filled without affecting the pore size or pore ordering as a function of dispersion of Mn-doped Fe 3 O 4 present as clusters within the channel structures of the mesoporous material. The magnetic properties along with the photocatalytic property of these MNPs were understood as a function of the particle size. The photocatalytic studies for the degradation studies of para-chlorophenol (p-CP) showed these MNPs to be very good photocatalysts with substantial apparent quantum efficiencies and turnover frequencies. The mechanism for the degradation of the p-CP solution as a function of particle size is postulated under the light of variation of magneto-photocatalytic property for the present series of MNPs.