Fabrication of magnetically recoverable and reusable MgFe2O4/Ag3PO4 composite for catalytic reduction of 4-Nitrophenol

Abstract

In recent years, an immense interest has been focused on to develop high-performance magnetic based nanocatalysts as they can be easily separated from the heterogeneous reaction mixture, without filtration/centrifugation process. Herein, a novel magnetically recoverable and reusable MgFe2O4/Ag3PO4 composite has been fabricated via a hydrothermal route to carry out 4-nitrophenol (4-NP) reduction reaction in aqueous medium. X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectral analyses revealed the formation of a well-defined composite between magnetic (MgFe2O4) and non-magnetic (Ag3PO4) phases. The band gap of Ag3PO4 decreased from 2.31 eV to 1.71 eV after making composite with MgFe2O4. The fabricated composite is magnetic in nature with saturation magnetization (MS) of 15 emu/g. The prepared materials have been employed as catalysts to drive 4-NP reduction using the mild reducing agent sodium borohydride (NaBH4) and the progress of the catalytic reaction was ascertained using UV–visible spectrophotometry. Results show that the fabricated MgFe2O4/Ag3PO4 composite demonstrated superior catalytic performance over the individual components (MgFe2O4 and Ag3PO4) of the composite. Moreover, the composite completed the 4-nitrophenol reduction reaction in 1 min whereas the Ag3PO4 achieved the same reduction reaction in 15 min, despite all the catalytic reduction reactions were performed under the identical conditions. Enhanced catalytic performance of the MgFe2O4/Ag3PO4 magnetic composite can be attributed to strong electronic coupling between MgFe2O4 and Ag3PO4 that facilitates the electrons transfer from borohydride to nitrophenol and thereby catalytic reduction reaction occurs. Furthermore, the composite catalyst was found to be phase stable even after 5 consecutive recycles.