ALMIR OLIVEIRA NETO

ALMIR OLIVEIRA NETO

(Fonte: Lattes)

Resumo

Possui graduação em Química pela Universidade Presbiteriana Mackenzie (1993), mestrado em Ciências e Engenharia de Materiais pela Universidade de São Paulo (1997), doutorado em Físico-Química pela Universidade de São Paulo (2001) e pós-doutorado pelo Instituto de Pesquisa Energéticas Nucleares (2001-2003). Atualmente é Pesquisador Titular III da Comissão Nacional de Energia Nuclear, alocado no Instituto de Pesquisa Energéticas Nucleares (IPEN/CNEN-SP). Tem experiência na área de Química, com ênfase em Físico-Química, atuando principalmente nos seguintes temas: células à combustível ácidas e alcalinas, eletrocatalisadores, oxidação de alcoóis, reação de redução de oxigênio, oxidação de metano a produtos de maior valor agregado, estudos do mecanismo de oxidação de moléculas orgânicas em infravermelho "in situ" , desenvolvimento de novos métodos de preparação de materiais nanométricos, síntese de nanoparticulas com diferentes orientações, síntese de nanomateriais por processos radiolíticos, síntese de bio eletrocatalisadores e desenvolvimento de anodos e catodos para uma célula a combustível tipo microbiana, oxidação da uréia, oxidação de fármacos utilizando técnicas eletroquímicas convencionais e desenvolvimento de reatores fotocatalíticos. (Texto extraído do Currículo Lattes em 04 out. 2021)

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Resultados de Busca

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Síntese da fase MAX Ti2AlN e aplicação como suporte de catalisador para reação de eletrooxidação do etanol
2024 - GUEDES-SILVA. C.C.; LAZAR, D.R.; FERREIRA, T.; BONIFACIO, R.N.; OTUBO, L.; LEAL NETO, R.N.; CARVALHO, F.M.; OLIVEIRA, A.
Fases MAX são carbetos e nitretos em camadas com estrutura hexagonal e fórmula geral Mn+1AXn onde n = 1–3, M representa um metal de transição, A é um elemento do grupo 13-14 e X é carbono ou nitrogênio. Até o momento, há mais de 150 fases MAX, combinando importantes propriedades das cerâmicas e dos metais, tais como boa condutividade elétrica e térmica, alto módulo de elasticidade, resistência ao choque térmico e a ataque químico. Nesse trabalho, a fase MAX Ti2AlN foi sintetizada pela reação em alta temperatura dos pós de titânio, alumínio e nitreto de titânio, previamente misturados e conformados por prensagem uniaxial. Em seguida, foram incorporados estanho e platina no material sintetizado, visando a confecção de catalisadores para reação de eletro-oxidação do etanol. As técnicas de caracterização utilizada foram: difração de raios X, microscopia eletrônica de varredura com emissão de campo, voltametria e cronoamperometria. A fase Ti2AlN foi obtida com sucesso e os catalisadores (Pt/MAX e PtSn/MAX) apresentaram bom desempenho na reação de eletro-oxidação do etanol, comparativamente ao material estado da arte Pt/C.
Nitreto de titânio bidimensional (MXene, Ti2N)
2024 - LAZAR, D.R.; FERREIRA, T.; OTUBO, A.; LEAL NETO, R.M.; CARVALHO, F.M.; GUEDES-SILVA, C.C.
A família de materiais denominada MXene inclui carbetos, nitretos e carbonitretos bidimensionais com fórmula geral Mn+1Xn, onde M é um metal de transição, X é carbono e/ou nitrogênio e n variando de 1 a 4. Também estão presentes na superfície, grupos funcionais de íons oxigênio, flúor, cloro ou hidroxila. Esses materiais são promissores em uma grande variedade de aplicações como nas áreas de estocagem de energia e conservação do meio ambiente. Nesse trabalho, a fase Ti2N foi sintetizada a partir da fase MAX Ti2AlN previamente obtida pela reação em estado líquido/sólido dos pós de titânio, alumínio e nitreto de titânio moídos e prensados. Em seguida, os materiais foram submetidos a tratamento térmico com sal fundido e caracterizados por difração de raios X e microscopia eletrônica de varredura com emissão de campo. Os resultados mostraram que as fases Ti2AlN e Ti2N foram obtidas majoritariamente, indicando o sucesso dos métodos de síntese e de exfoliação utilizados.
Synthesis and performance of PdAu/ITO electrocatalysts in urea oxidation reaction
2024 - ABREU, ISABELY M.G.; MAIA, VICTORIA A.; SOUZA, RODRIGO F.B. de; NETO, ALMIR O.
PdAu electrocatalysts were prepared in different atomic compositions supported on ITO by sodium Borohydride process. XRD results show intense crystalline peaks related to ITO, which may mask the appearance of less crystalline Pd or Au phases. Transmission results indicate agglomeration of palladium and gold nanoparticles on the support, a phenomenon compatible with metal oxide supports. Cyclic voltammograms in the absence of urea display characteristics commonly observed for PdAu electrodes, with an increase in oxygenated species compared to pure Pd or Au. Voltammograms in the presence of urea showed oxidation processes and lower current values, indicating catalyst deactivation processes. PdAu 75:25 demonstrated higher power density values compared to other prepared electrocatalysts, suggesting a synergy between Pd and Au for urea oxidation reaction.
Development of hydrophobic graphenoid layer on Portland cement for non-thermal plasma method
2024 - PEREIRA FILHO, N.G.; SOARES, E.P.; FERREIRA, J.C.; SOUZA, R.F.B. de; ANDRADE, D.A.; NETO, A.O.
This study focuses on the development of hydrophobic layer on Portland cement using graphenoid materials to enhance impermeability and hydrophobicity. X-ray diffraction analysis indicated that characteristic peaks associated with concrete, such as ettringite, calcium hydroxide, and calcite, remained intact. The application of graphenoid material produced by non-thermal plasma resulted in the formation of carbonaceous structures, minimally affecting the overall cement structure. Raman spectroscopy provided detailed insights into the composition, highlighting the presence of specific and indicating boundary defects. Moreover, contact angle measurements confirmed a substantial increase in hydrophobicity for the graphene-coated cement, with an average angle of 117° ± 4.72° demonstrated graphenoid material layers deposited over structural defects, effectively waterproofing and enhancing local hydrophobicity.
Exfoliation of titanium nitride using a non-thermal plasma process
2024 - ZAMBIAZI, PRISCILA J.; LAZAR, DOLORES R.R.; OTUBO, LARISSA; SOUZA, RODRIGO F.B. de; OLIVEIRA NETO, ALMIR; GUEDES-SLVA, CECILIA C.
In this study, we present a novel approach for the exfoliation of titanium nitride (TiN) powders utilizing a rapid, facile, and environmentally friendly non-thermal plasma method. This method involves the use of an electric arc and nitrogen as the ambient gas at room temperature to generate ionized particles. These ionized species interact with the ceramic crystal of TiN, resulting in a pronounced structural expansion. The exfoliated TiN products were comprehensively characterized using transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. Remarkably, the cubic crystal structure of TiN was effectively retained, while the (200) crystal plane d-spacing increased from 2.08 to 3.09 Å, accompanied by a reduction in crystallite size and alterations in Raman vibrational modes. Collectively, these findings provide compelling evidence for the successful exfoliation of TiN structures using our innovative non-thermal plasma method, opening up exciting possibilities for advanced material applications.
Bioprospecting of mangrove filamentous fungi for the biodegradation of polyethylene microplastics
2024 - AGUIAR, ARTHUR; GAMA, LETICIA; FORNARI, MILENE; NETO, ALMIR; SOUZA, RODRIGO de; PERNA, RAFAEL; CASTRO, LAURA; KOVACS, STELLA; SIMOES, MARTA F.; FERREIRA, NELSON; DOMINGUEZ, YOANNIS; CASTRO, LEANDRO de; OTTONI, CRISTIANE
The accumulation of microplastics (MPs) in the environment has been a bottleneck for scientific society. Several approaches have been described as possibilities for reducing MPs in aquatic and terrestrial ecosystems; however, most of them are not environmentally friendly. Filamentous fungi (Ff) cells are currently considered a promising solution as a treatment for MPs. Therefore, the present study reports the potential ability of Ff isolated from mangrove sediments to biodegrade low-density polyethylene MPs (LDPEMPs). Six Ff strains were grown in batch cultures for 28 days, and one of them, Aspergillus sp. (AQ3A), showed the most prominent profile to biodegrade polymeric compounds. After morphological and molecular analysis, all strains were identified as belonging to the genera Aspergillus (MQ1C, AQ2A and AQ3A), Penicillium (MQ1A), and Trichoderma (MQ1B and MQ2A). The strain Aspergillus sp. (AQ3A) showed the most promising results with a LDPEMPs reduction rate of 47% and biomass formation of 0.0890 g·mL−1. Complementary studies with Aspergillus sp. (AQ3A) using Fourier-transform infrared spectroscopy (FTIR) highlighted changes in the molecular structure of LDPEMPs. These results indicate that Ff can contribute to the biodegradation of LDPEMPs. However, other parameters, mainly associated with the enzymes that are involved in this biodegradation process, need to be explored.
Nuclear power plants
2024 - GIOVEDI, C.; ABE, A.Y.; OLIVEIRA, A.; DE MICHELI, L.
Innovative deposition of platinum-graphene on alumina for passive autocatalytic recombiners to improve nuclear safety
2024 - SILVESTRIN, G.; SOUZA, R.F.B. de; NETO, A.O.; DE MICHELI, L.; GIOVEDI, C.
Optimizing PtSn composition in direct sugarcane extract fuel cells
2024 - VILLARDI, BRUNO D.Q.; MAIA, VICTORIA A.; NANDENHA, JULIO; ZAMBIAZI, PRISCILLA J.; SOUZA, RODRIGO F.B. de; NETO, ALMIR O.
Pt90Sn10/C composition exhibited a strong maximum power density value and a good sugar oxidation response in sugar extract solution in comparison with others electrocatalysts prepared. Pt90Sn10/C demonstrated a maximum power density approximately 93% higher than that of Pt80Sn20/C, which is the second most active material and more than 8 times bigger than Pt/C. The primary difference between the two lies in glucose consumption, which is approximately 90% higher in Pt90Sn10/C. It is important to highlight that in the more active materials; fructose consumption remains relatively constant, ranging between 7 and 8%. The enhanced performance could be attributed to both the altered electronic properties resulting from tin integration into the platinum crystal lattice and the activation of water at less positive potentials by a bifunctional mechanism. XRD results showed that the lattice parameters were expanded indicating the insertion of Sn to Pt, while that cyclic voltammetry showed that all materials present the hydrogen adsorption–desorption region over Pt (− 0.2 to 0.15 V); however, when increasing the tin content in the catalyst, the region decreases the definition and is associated with the presence of transition metals such as Sn. TEM images and histograms for PtSn showed the increase in the average particle size accompanying the tin enrichment in the composition; this effect could be tin oxide in material surface and is in agreement with other works.
Innovative lead-carbon battery utilizing electrode-electrolyte assembly inspired by PEM-FC architecture
2024 - SOUZA, RODRIGO F.B. de; SILVESTRIN, GABRIEL A.; CONCEICAO, FELIPE G. da; MAIA, VICTORIA A.; OTUBO, LARISSA; NETO, ALMIR O.; SOARES, EDSON P.
This study explores the innovative integration of a lead‑carbon battery with an electrode-electrolyte assembly inspired by Proton Exchange Membrane Fuel Cell (PEM-FC) architecture. The lead‑carbon material, synthesized with a 40 % mass ratio using the Flash Joule Heating Method, exhibits predominant Pb0 and PbO phases, as observed in lattice parameter fringes, with additional detection of the PbO2 phase. The resulting Carbon-Lead Acid Battery (CLAB) demonstrates a specific capacity of 11.2 mAh g−1. The incorporation of carbon enhances nanoparticle stability, yielding a highly stable battery performance over 100 cycles, with discharge potential variations of <2 %. This innovative CLAB assembly not only showcases stable performance and also introduces the potential for constructing flexible lead batteries, expanding technological applications. The study provides comprehensive insights into the synthesis, performance, and prospects of this novel lead‑carbon battery architecture, emphasizing its significance in the realm of energy storage solutions.