| Autor: |
Vasilev A; A.V. Topchiev Institute of Petrochemical Synthesis RAS, Leninskiy Prospekt 29, Moscow 119991, Russia., Efimov M; A.V. Topchiev Institute of Petrochemical Synthesis RAS, Leninskiy Prospekt 29, Moscow 119991, Russia., Muratov D; A.V. Topchiev Institute of Petrochemical Synthesis RAS, Leninskiy Prospekt 29, Moscow 119991, Russia., Chernavskii P; A.V. Topchiev Institute of Petrochemical Synthesis RAS, Leninskiy Prospekt 29, Moscow 119991, Russia.; Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1-3, Moscow 119991, Russia., Cherednichenko K; Department of Physical and Colloidal Chemistry, National University of Oil and Gas 'Gubkin University', Leninskiy Prospekt 65, Moscow 119991, Russia., Dzidziguri E; Department of Functional Nanosystems and High-Temperature Materials, National University of Science and Technology 'MISiS', Leninskiy Prospekt 4, Moscow 119049, Russia., Karpacheva G; A.V. Topchiev Institute of Petrochemical Synthesis RAS, Leninskiy Prospekt 29, Moscow 119991, Russia. |
| Abstrakt: |
Fe-Co alloy nanoparticles with different sizes, supported by carbon derived from several polymers, namely polyacrylonitrile, polyvinyl alcohol and chitosan, have been synthesized by a one-pot method involving simultaneous metal nanoparticle formation and polymer carbonization. The method involves the joint dissolution of metal salts and a polymer, followed by annealing of the resulting dried film. Detailed XRD analysis confirmed the formation of Fe-Co alloy nanoparticles in each sample, regardless of the initial polymer used. Transmission electron microscopy images showed that the Fe-Co nanoparticles were all spherical, were homogeneously distributed within the carbon support and varied by size depending on the initial polymer nature and synthesis temperature. Fe-Co nanoparticles supported by polyacrylonitrile-derived carbon exhibited the smallest size (6-12 nm), whereas nanoparticles on chitosan-derived carbon support were characterized by the largest particle size (13-38 nm). The size dependence of magnetic properties were studied by a vibrating sample magnetometer at room temperature. For the first time, the critical particle size of Fe-Co alloy nanoparticles with equiatomic composition has been experimentally determined as 13 nm, indicating the transition of magnetic properties from ferromagnetic to superparamagnetic. |
