The paper presents a comparative study of the activity of magnetite (FeO) and copper and cobalt ferrites with the structure of a cubic spinel synthesized by combustion of glycine-nitrate precursors in the reactions of ammonia borane (NHBH) hydrolysis and hydrothermolysis. It was shown that the use of copper ferrite in the studied reactions of NHBH dehydrogenation has the advantages of a high catalytic activity and the absence of an induction period in the H generation curve due to the activating action of copper on the reduction of iron. Two methods have been proposed to improve catalytic activity of FeO-based systems: (1) replacement of a portion of Fe cations in the spinel by active cations including Cu and (2) preparation of highly dispersed multiphase oxide systems, involving oxide of copper.
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http://dx.doi.org/10.3390/ma14185422 | DOI Listing |
Nanoscale
January 2025
J. Heyrovský Institute of Physical Chemistry, Czech Acad. Sci., Dolejškova 3, CZ-18200, Prague 8, Czech Republic.
Compositionally complex doping of spinel oxides toward high-entropy oxides is expected to enhance their electrochemical performance substantially. We successfully prepared high-entropy compounds, the oxide (ZnMgCoCu)FeO (HEOFe), lithiated oxyfluoride Li(ZnMgCoCu)FeOF (LiHEOFeF), and lithiated oxychloride Li(ZnMgCoCu)FeOCl (LiHEOFeCl) with a spinel-based cubic structure by ball milling and subsequent heat treatment. The products exhibit particles with sizes from 50 to 200 nm with a homogeneous atomic distribution.
View Article and Find Full Text PDFHeliyon
December 2024
Department of Physics, University of Dhaka, Dhaka, 1000, Bangladesh.
This research presents an explicit analysis of the effects of sintering temperature (T) on the structural, morphological, magnetic, and optical properties of CuMgFeO nanoferrites synthesized via the sol-gel method. To accomplish it, Cu-Mg ferrite NPs were sintered at temperatures ranging from 300 to 800 °C in increments of 100 with a constant holding duration of 5 h. Thermogravimetric analysis was used to observe the degradation of organic components and the thermally stable zone of the material.
View Article and Find Full Text PDFMaterials (Basel)
November 2024
Center of Physics of Minho and Porto Universities (CF-UM-UP), Laboratory for Materials and Emergent Technologies (LaPMET), Departamento de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
Laser ablation was used to successfully fabricate multiferroic bilayer thin films, composed of BaTiO (BTO) and CoFeO (CFO), on highly doped (100) Si substrates. This study investigates the influence of BaTiO layer thickness (50-220 nm) on the films' structural, magnetic, and dielectric properties. The dense, polycrystalline films exhibited a tetragonal BaTiO phase and a cubic spinel CoFeO layer.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, China.
Despite the extensive studies on the adsorption and activation of hydrogen over metal oxides, it remains a challenge to investigate the structure-dependent activation of hydrogen and its selectivity mechanism in hydrogenation reactions. Herein we take spinel and solid solution MnGaO with a similar bulk chemical composition and study the hydrogen activation mechanism and reactivity in syngas conversion. The results show that MnGaO-Solid Solution (MnGaO-SS) is a typical Mn-doped hexagonal close-packed (HCP) GaO with a Ga-rich surface.
View Article and Find Full Text PDFSci Rep
November 2024
Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, 431004, India.
The nanoscale spinel structured ferrites co-doped with multi-valence ions are of great interest and proving to be promising for numerous applications. In light of this, herein we report tetravalent titanium ions (Ti) and divalent zinc ions (Zn) co-doped nickel ferrites with generic formula of NiFeTiZnO (x = 0.00 ≤ x ≤ 0.
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