Solvothermal synthesis of Co1-xNixFe2O4 nanoparticles and its application in ammonia vapors detection

Magnetic Co1-xNixFe2O4 nanoparticles (NPs) were successfully synthesized via a solvothermal method using ethylene glycol as solvent. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM) and gas sensing test. The experimental results showed that the magnetic Co1-xNixFe2O4 were composed of single phase spinel structure and the average crystallite size in the NPs is between 5.8 and 9.8 nm; the NPs are spherical with an average particle size of about 40-90 nm; the saturation magnetization (M-s) of the Co1-xNixFe2O4 NPs decreased linearly as the contents of Ni2+ increased; and the as-prepared Co1-xNixFe2O4 NPs have a higher selectivity toward ammonia vapors and the Co0.8Ni0.2Fe2O4 has the best gas sensitivity of Co1-xNixFe2O4 (0 <= x <= 1) NPs at working voltage of 8 V. (C)2012. Chinese Materials Research Society. Production and hosting by Elsevier B.V. All rights reserved.