Magnetic and catalytic properties of inverse spinel CuFe 2 O 4 nanoparticles S. Anandan a,b,⇑ , T. Selvamani a , G. Guru Prasad a , A. M. Asiri c , J. J. Wu b,⇑ a Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015, India b Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan c The Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21413, Saudi Arabia article info Article history: Received 2 August 2016 Received in revised form 14 October 2016 Accepted 16 February 2017 Available online 20 February 2017 Keywords: Ferrites Magnetic materials Mössbauer spectroscopy Catalytic properties abstract In this research, inverse spinel copper ferrite nanoparticles (CuFe 2 O 4 NPs) were synthesized via citrate- nitrate combustion method. The crystal structure, particle size, morphology and magnetic studies were investigated using various instrumental tools to illustrate the formation of the inverse spinel structure. Mossbauer spectrometry identified Fe is located both in the tetrahedral and octahedral site in the ratio (40:60) and the observed magnetic parameters values such as saturation magnetization (M s = 20.62 emu g 1 ), remnant magnetization (M r = 11.66 emu g 1 ) and coercivity (H c = 63.1 mTesla) revealed that the synthesized CuFe 2 O 4 NPs have a typical ferromagnetic behaviour. Also tested CuFe 2 O 4 nanoparticles as a photocatalyst for the decolourisation of methylene blue (MB) in the presence of peroxydisulphate as the oxidant. Ó 2017 Elsevier B.V. All rights reserved. 1. Introduction Ferrites are a class of compounds which attracts the attention of many researchers and are being widely investigated due to its omnipotent properties and versatile applications [1–4]. Ferrites have a general formula MFe 2 O 4 where M is either divalent transi- tion metal ions or alkaline earth metal ion. The metal ion arrange- ments, structural orientation, and morphology are the key factors contributing to its physical, magnetic, optical and electrical proper- ties. Ferrites with normal spinel structures have divalent and triva- lent ions occupying 1/8th of the tetrahedral voids and ½ th of the octahedral voids respectively consist of a cubic close packed array of oxygen ions, whereas in the inverse spinel structure the trivalent iron prefers the occupancy of both the voids [5–7]. Depending upon the occupancy and site preferences between the divalent metal ions and trivalent ions their properties can be altered and tuned. Among the existing transition metal ferrites, copper ferrite is a unique example of inverse spinel where Fe 3+ cations occupy both the tetrahedral and half the octahedral sites, whereas the Cu 2+ cations present in the remaining half of the octahedral sites and in addition to the cubic phase it also has tetragonal phase which may be due to Jahn-Teller distortion which accounts for the changes in various properties and utilities [8,9]. The copper fer- rite band gap is approximately 1.6 eV making it effective under vis- ible light irradiation [10–12]. A key factor further driving the attention of researchers in this material is the magnetic properties, because the ease of separation, recovery, and reusability of Copper ferrite may achieve very easily [13–15]. Copper ferrite is formed in two crystal structures namely cubic spinel and tetragonal phases depending upon the method of prepa- ration and annealing temperature. General preparative methods of copper ferrite include hydrothermal method [16], sonochemical method [17], citrate-nitrate [18,19], sol-gel method [20], co- precipitation method [21,22], and solid-state method [23]. So far, CuFe 2 O 4 nanostructural materials with various morphologies have been reported, such as nanoparticles [20], nanospheres [24], nano spindles [17], nanofibers [25], nanotubes [26], nanorings [26], nanorods [27] and honeycomb structures [28]. As far as the appli- cation of copper ferrite is concerned, it is widely applied in various fields that include heterogeneous catalysis [11,12], photocatalysis [11], photocatalytic H 2 evolution activity [29], energy storage [16], anode material for high-performance batteries [20], high- density magnetic storage media, for high-performance electromag- netic and spintronic devices [30,31]. Its application is further extended to biomedicine and drug delivery [32], magnetic reso- nance imaging [33], magnetic separation of cancer cells and antibacterial activities [34]. As far as in the field of photocatalysis and degradation of organic substances are concerned CuFe 2 O 4 have a good scope and has given promising outcomes to name a few, http://dx.doi.org/10.1016/j.jmmm.2017.02.026 0304-8853/Ó 2017 Elsevier B.V. All rights reserved. ⇑ Corresponding authors at: Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015, India (S. Anandan). E-mail addresses: sanand@nitt.edu (S. Anandan), jjwu@fcu.edu.tw (J.J. Wu). Journal of Magnetism and Magnetic Materials 432 (2017) 437–443 Contents lists available at ScienceDirect Journal of Magnetism and Magnetic Materials journal homepage: www.elsevier.com/locate/jmmm