Тип публикации: статья из журнала
Год издания: 2026
Идентификатор DOI: 10.1016/j.matchemphys.2026.132589
Аннотация: In this work, phase-dependent mechanisms of charge transfer and dielectric relaxation in nanostructured cobalt oxides CoOx synthesized by the vacuum arc method at different pressures of the Ar + O2 gas mixture were studied. The phase composition and crystallinity of the samples were characterized by X-ray diffraction, thermal analyПоказать полностьюsis, Infrared and Raman spectroscopy; morphology and size distribution were determined using electron microscopy. The electrical properties were studied by impedance spectroscopy in the range of 102–108 Hz with an analysis of the frequency dependences of the complex permittivity, loss tangent, and impedance hodographs. It is shown that from reduced Co-rich composites to spinel-rich intermediate-pressure systems is accompanied by a transition from conductive mechanisms (dominated by Co0) to localized transport involving small polarons and pronounced Maxwell-Wagner interfacial polarization at grain and phase boundaries. It is established that the Co/CoO/Co3O4 phase ratio, the nanoscale size, and the defectiveness of intergranular regions determine the contribution of grain and intergranular conductivity, the nature of non-Debye relaxations, and the level of dielectric loss. The obtained regularities provide a physical basis for targeted optimization of the vacuum-arc synthesis modes of CoOx nanopowders – gas-sensitive sensors, electrochemical electrodes, and (electro)catalytic systems.
Журнал: Materials Chemistry and Physics
Выпуск журнала: Т. 360
Номера страниц: 132589
ISSN журнала: 02540584
Издатель: Elsevier Science Publishing Company, Inc.