KATIUSSE SOARES DE SOUZA
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Resumo IPEN-doc 31004 Molybdenum (II) acetate as a precursor for molybdenum trioxide2024 - SOUZA, KATIUSSE S. de; SILVA, CRYSTIAN W.C. da; BURIMOVA, ANASTASIA; PEREIRA, LUCIANO F.; OTUBO, LARISSA; CARBONARI, ARTUR W.; FREITAS, RAFAEL S. deTransition metal structures (such as cobalt, nickel, and molybdenium) have been the subject of studies in recent years due to their electrical, catalytic and magnetic properties. Orthorhombic molybdenum trioxide (α-MoO3) is relevant because it is an antioxidant material, leading to its catalytic properties that are influenced by the valence state of molybdenum ions and the local environment where they are inserted. These structures have been investigated in developments of sensors, energy storage and the formulation of gels for the treatment of chronic diseases [1]. In this perspective, the present work proposes the use of the molybdenum (II) acetate as a metallic precursor for obtaining α-MoO3 structures by the thermal decomposition method [2]. The Mo (II) acetate belongs to a group of metal complexes composed of two highly correlated Mo ions, in which each cations are connected to complexes containing oxygen. This reagent could favor, in specific chemical route, the crystallization of MoxOy [2][3]. The syntheses yields were characterized by X-ray diffraction (XDR), scanning electron microscopy (SEM), and energy-dispersive analysis (EDS). The X-ray diffraction results suggested α-MoO3 crystallite of the 77 nm (by the Scherrer equation). By means of microscopy analysis were observed that the obtained morphology is microrod-like, with a of approximately 774 nm and a length of the 37 micrometers. The EDS analysis only showed energies related to molybdenum (Mo) and oxygen (O), confirming the purity of the obtained material.Resumo IPEN-doc 30996 Development of flexible magnetic films by the incorporation of Ni/Ni3C nanoparticles in a matrix of Amazonian tannic extract (Myrcia atramentifera)2024 - SILVA, CRYSTIAN W.C. da; SOUZA, KATIUSSE S. de; SILVA, BARBARA P.G.; FREITAS, RAFAEL S. de; LAZAR, DOLORES R.R.; PASCA, GABRIEL A.C.; CARBONARI, ARTUR W.; OTUBO, LARISSAThe development of nanostructured magnetic materials based on Ni and its compounds (Ni/Ni3C) has been the objective of scientific research due to the versatility of applications that these materials. In this context, magnetic films can be applied in a variety of technologies such as data storage, flexible spintronics, chemical detection, and magnetic sensors.[1] Additionally, the growing prospect of obtaining environmentally eco-friendly materials has promoted the use of vegetable matrices for film synthesis, such as tannins, for example. In this work, we report the fabrication of flexible magnetic films on paper substrates by adding Ni/Ni3C nanoparticles to the tannin extract matrix of the Amazonian species Myrcea atramentífera.[2] The tannin extract solution was obtained by processing the species' bark through grinding, sieving, and water extraction for 8 hours at 70°C, followed by filtration and concentration. After this step, a tannin extract suspension containing 0.1% Ni/Ni3C was prepared by dispersion in an ultrasonic processor. The suspension was dispersed onto a paper substrate and dried at 30 °C for 10 minutes. The films were characterized by XRD, SEM, AFM, and TGA/DSC measurements. The structural and morphological results indicate the formation of continuous films with dispersed nanoparticles. Thermal analysis results suggest that the nanoparticles dispersed in the films maintain structural stability up to 350 °C. The films present macroscopic magnetic response at room temperature, which can be attributed to the presence of nanoparticles with a coercive field of 100 Oe and saturation magnetization of 26 emu/g. [3]Resumo IPEN-doc 30169 Comparative local analysis of Ni/Ni3C nanoparticles synthed with oleylamine/oleic acid and oleylamine/palm kernel oil ligand pairs2023 - SILVA, CRYSTIAN W.C. da; OTUBO, LARISSA; SOUZA, KATIUSSE S. de; CARBONARI, ARTUR W.; CORREA, BRUNO S.; FREITAS, RAFAEL S. de; PASCA, GABRIEL A.; COSTA, CLEIDILANE S.In recent decades, Ni/Ni3C nanoparticles have been a topic of interest, especially for their catalytic and magnetic properties, promising as electrocatalysis, for example [1]. These systems are usually obtained by chemical methods, in the presence of ligands responsible for controlling their structure and morphology [2]. In this work, we carried out a comparative study of the hyperfine interactions occurring in Ni/Ni3C nanoparticles, synthed by thermal decomposition in the presence of oleylamine/oleic acid and oleylamine/palm kernel oil ligand pairs, at 513 K, for 3 hours. The local analysis was performed using perturbed correlation spectroscopy (PAC) in the temperature range from 30K to 300K, using the 111Cd probe, implanted in the samples by diffusion, during the synthesis. The parameters of the hyperfine interactions were compared to the results obtained by XRD, TEM and magnetization, indicating the obtainment of Ni/Ni3c nanoparticles of the core-shell type, showing a higher Ni3C content, greater distribution and lower saturation magnetization for nanoparticles synthed with palm kernel oil compared to those obtained with oleic acid. In addition, the hyperfine parameters showed the existence of regions with a quadrupole frequency of 24 MHz and a magnetic hyperfine field of 1T in both samples, which may be indicative of carbon-deficient Ni3C regions, predicted in the literature [3].