CoCuFe2O4 Ferrites Hosted in Activated Carbon from Used Motor Oils and Ceria-Based Nanocomposites as Catalysts for Hydrogen Production

This study focuses on the synthesis of CoCuFe₂O₄ mixed ferrites supported on nanoporous carbon materials. The carbon supports were derived from two mixtures: a mixture of spent motor oil and pine wood chips (designated as AC-A), and mixture of spent motor oil and crushed coal obtained from the Chukurovo mine (designated as AC-B). Additionally, two types of carbon components – nanodiamond and graphene oxide were used for the synthesis of nanosized ceria-based hybrid nanocomposites. The structural and physicochemical properties of the resulting materials were comprehensively characterized using X-ray diffraction (XRD), nitrogen physisorption, Mössbauer spectroscopy, and temperature-programmed reduction (TPR) analysis. The results revealed that the active phase deposited on the carbon supports consists of a complex mixture of finely dispersed ferrite nanoparticles as well as small CeO₂ crystallites in the hybrid nanocomposites. The dispersion and phase composition were found to be strongly influenced by the textural properties of the respective carbon support. Among the investigated materials, the graphene oxide-modified composites exhibited superior catalytic performance for hydrogen production via methanol decomposition.