Novel core–shell Fe3O4/NiO nanofibers for the photocatalytic degradation of active pharmaceutical compounds

Abstract

Coaxial electrospinning is a facile and versatile method for the fabrication of core–shell metal oxides for environmental applications. The use of core–shell metal oxide nanofibers with a magnetic core and photocatalytic shell is a new approach for the photocatalytic degradation of active pharmaceutical compounds (APCs) in water and the removal of photocatalysts by a magnetic field. In the present work, we report the fabrication and characterization of novel Fe₃O₄–Fe₂NiO₄/NiO core–shell nanofibers with advanced structural, optical, magnetic and photocatalytic properties via co-axial electrospinning. The aim of this work is to investigate the photocatalytic degradation of acetaminophen by the novel metal oxide core–shell nanofibers with different structural properties. The core–shell nanofibers were fabricated using constant core solution parameters (PAN 7.55% w/w and Fe nitrate 5.5% w/w) and variable shell solution parameters (PVP 11.4–11.1% w/w and Ni acetate 5.29–8.51% w/w). The phase transition of Fe₃O₄ → Fe₂NiO₄ was observed in the core. The Fe₃O₄–Fe₂NiO₄/NiO nanofibers exhibit a high optical absorption in the visible range (band gaps of 2 eV and 2.2 eV), significant magnetization (15 A m² kg⁻¹) and high efficiency for the degradation of methylene blue (80%) and acetaminophen (45%). The photocatalytic properties of the Fe₃O₄–Fe₂NiO₄/NiO nanofibers significantly depended on their core and shell chemical composition. The formation of spinel Fe₂NiO₄ in the core was one of the factors that limited the photocatalytic performance of the core–shell nanofibers. Thus, their photocatalytic performance could be improved by adjusting the core and shell fabrication parameters. The advanced properties of the Fe₃O₄–Fe₂NiO₄/NiO core–shell nanofibers highlight their applications for the efficient degradation of active pharmaceutical compounds in water resources.