Structural, magnetic and catalytic properties of cobalt chromite obtained through precursor method. (February 2015)

• Record Type: Journal Article
• Authors: Gingasu, Dana; Mindru, Ioana; Culita, Daniela C.; Patron, Luminita; Calderon-Moreno, Jose Maria; Osiceanu, Petre; Preda, Silviu; Oprea, Ovidiu; Parvulescu, Viorica; Teodorescu, Valentin; Walsh, James P.S.
• Is Part Of: Materials research bulletin. Volume 62(2015:Feb.)
• Page Start: 52
• Page End: 64
• Publication Date: 2015-02
• Subjects: A. Oxides -- B. Chemical synthesis -- C. X-ray diffraction -- C. Transmission electron microscopy -- D. Magnetic properties; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2014.11.009
• Languages: English
• ISSNs: 0025-5408

Abstract

Graphical abstract: Highlights: CoCr2 O4 was synthesized through the tartarate and gluconate precursor routes. Both routes led to the formation of the single-phase CoCr2 O4 . The crystallite size was in the range of 14–21 nm. CoCr2 O4 samples presented ferrimagnetic ordering below Currie temperature T c = 97 K. CoCr2 O4 samples presented catalytic performance in the total oxidation of CH4 . Abstract: Cobalt chromite (CoCr2 O4 ) was synthesized through the precursor method. The precursors: (NH4 )3 [CoCr2 (C4 O6 H4 )4 (OH)3 ]·4H2 O, (NH4 )3 [CoCr2 (C6 O7 H10 )4 (C6 O7 H9 )]·5H2 O were characterized by elemental chemical analysis, infrared (IR) and ultraviolet–visible (UV–vis) spectroscopy, and thermal analysis. The final oxides were characterized by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM/TEM), UV–vis, IR, Raman spectroscopy (RS), magnetic measurements, N2 adsorption–desorption analyses and X-ray photoelectron spectroscopy (XPS). XRD confirmed the cubic CoCr2 O4 phase only and determined average crystallite sizes between 14 and 21 nm. Electron microscopy revealed morphology corresponding to the complete crystallization into cubic CoCr2 O4 . All the samples presented ferrimagnetic ordering below the Currie temperature ( T c ), and a phase transition at T s ∼26 K attributed to the onset of long-range spiral magnetic order. The CoCr2 O4 nanoparticles generated through the gluconate route following calcination at 700 °C for 1 h were found to have the best catalytic activity in the total oxidation of methane.