https://repositorio.ufms.br/handle/123456789/6393 2026-04-16T04:08:08Z https://repositorio.ufms.br/handle/123456789/14282 Título: CONVERSÃO FOTOELETROQUÍMICA DE METANO EM ENERGIA UTILIZANDO FOTOCÉLULAS A COMBUSTÍVEL BASEADAS EM FOTOÂNODOS DE BiVO4/CoOx Abstract: Climate change associated with greenhouse gas emissions has driven the search for technologies capable of mitigating environmental impacts while simultaneously enabling sustainable energy generation. In this context, methane stands out due to its high global warming potential and elevated energy content, making it a strategic target for energy valorization processes. Among the available conversion technologies, photoelectrocatalysis emerges as a promising approach by employing solar energy to drive electrochemical reactions, combining energy recovery with environmental mitigation. This work investigates the performance of a methane-fed photo fuel cell (PFC) based on bismuth vanadate (BiVO4) photoanodes surface-modified with cobalt oxide (CoOx). BiVO4 has attracted significant attention as a photoanode material due to its suitable band gap of approximately 2.4 eV, enabling visible light absorption, chemical stability in aqueous solution, and relatively low cost, making it attractive for photoelectrochemical applications. The photoanodes were synthesized by electrodeposition followed by thermal conversion, while the CoOx cocatalyst was deposited on the surface through chemical impregnation and thermal treatment. Structural, morphological, optical, and electronic characterizations confirmed the preservation of the monoclinic phase of BiVO4, with an unchanged band gap of 2.46 eV, indicating that the modification predominantly affects the semiconductor/electrolyte interface. Mott–Schottky analysis revealed a shift in the flat-band potential from −0.02 to 0.15 VRHE and an increase in charge carrier density after CoOx modification. Electrochemical impedance spectroscopy demonstrated a significant reduction in polarization resistance, indicating improved charge transfer kinetics. During PFC operation, the BiVO4/CoOx photoanode exhibited a 64% increase in maximum power density when the anolyte was saturated with methane, reaching 0.38 mW under continuous flow conditions. These results demonstrate that the use of CoOx as a cocatalyst is an effective strategy to enhance the photoelectrochemical performance of BiVO4, highlighting the potential of this system for methane energy valorization and sustainable electricity generation. Tipo: Trabalho de Conclusão de Curso 2026-01-01T00:00:00Z https://repositorio.ufms.br/handle/123456789/14036 Título: PERFIL ESPECTRAL DE AZEITES DE OLIVA: ANÁLISE REGIOESPECÍFICA POR RMN DE 13C Abstract: To validate the use of 13C Nuclear Magnetic Resonance (NMR) combined with chemometrics as a precise method to detect the adulteration of olive oil with lower value-added oils. Tipo: Trabalho de Conclusão de Curso 2025-01-01T00:00:00Z https://repositorio.ufms.br/handle/123456789/13672 Título: Compatibilidade do solo sul matogrossense para plantação de eucalipto Abstract: Physical, chemical, and geographic composition are suitable for eucalyptus planting Tipo: Trabalho de Conclusão de Curso 2025-01-01T00:00:00Z https://repositorio.ufms.br/handle/123456789/13581 Título: ISOLAMENTO E CARACTERIZAÇÃO ESTRUTURAL DE ALCALOIDES EM OCOTEA DIOSPYRIFOLIA (LAURACEAE) Abstract: Natural products are recognized as valuable sources of bioactive molecules with therapeutic potential and are widely used as starting points for the development of new drugs and phytotherapeutics. Among these, alkaloids stand out for their structural diversity and broad spectrum of pharmacological activities, making them important targets in the bioprospecting of plant species. The Lauraceae family, widely distributed in tropical and subtropical regions, is notable for its richness in secondary metabolites such as terpenes, polyphenols, phenylpropanoids, and especially alkaloids. Within this family, the genus Ocotea is particularly relevant, with Ocotea diospyrifolia (Meisn.) Mez being a native South American species traditionally used for treating colds, inflammation, and other ailments. Although preliminary studies have reported antioxidant, antimicrobial, acaricidal, cytotoxic, and anti-inflammatory activities in extracts and essential oils of this species, its bioactive compounds remain largely uncharacterized at the molecular level. This study aimed to isolate, purify, and structurally characterize alkaloids from the alkaloid-rich fraction of O. diospyrifolia, thereby contributing to the phytochemical knowledge of the species and identifying potential bioactive compounds. Plant material was collected in the Cerrado and Pantanal biomes, dried, ground, and extracted with 70% ethanol. The alkaloid fraction was obtained through acid-base partitioning and purified by semi-preparative high-performance liquid chromatography (HPLC-DAD). Isolated compounds were analyzed by high-resolution mass spectrometry (UHPLC-HRMS) and nuclear magnetic resonance (1D and 2D NMR). A total of 37 fractions were obtained, and four alkaloids were identified: reticuline, boldine, isoboldine, and laurotetanine, the latter being confirmed through long-range correlations in HMBC spectra. The crude alkaloid extract also showed signals compatible with other aporphine- and isocorydine-type alkaloids. Furthermore, previous biological assays revealed approximately 40% anti-leukemic activity against the KG-1 cell line, indicating a relevant cytotoxic potential. These results highlight O. diospyrifolia as a promising source of alkaloids with pharmacological relevance, especially for developing new bioactive prototypes targeting neoplastic diseases. This study also reinforces the value of Brazilian biodiversity and ethnopharmacological knowledge through integrated phytochemical and bioactivity research. Tipo: Trabalho de Conclusão de Curso 2025-01-01T00:00:00Z