RODRIGO FERNANDO BRAMBILLA DE SOUZA

RODRIGO FERNANDO BRAMBILLA DE SOUZA

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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.
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.
Enhanced carbon monoxide tolerance of platinum nanoparticles synthesized through the Flash Joule Heating Method
2024 - NANDENHA, JULIO; SILVESTRIN, GABRIEL; OTUBO, LARISSA; ANDRADE, DELVONEI A.; SOUZA, RODRIGO F.B. de; ANTOLINI, ERMETE; NETO, ALMIR O.
Was employ the Flash Joule Heating Method (FJHM) to synthesize carbon-supported Pt nanoparticles. In this method, an aqueous solution of the Pt precursorH2PtCl6·6 H2O is introduced into a reactor containing Vulcan XC 72 carbon. Subsequently, the mixture undergoes 50 cycles of discharges at 100 coulombs per discharge. Comparative XRD analysis with a commercially prepared Pt/C BASF, utilizing a reduction deposition method, reveals an expansion in the interplanar spacing of the platinum crystal lattice in the FJHM-prepared Pt/C catalyst (FJHM-Pt/C). This expansion suggests the emergence of structural defects, a finding confirmed by TEM images displaying distinct step-like features on the FJHM-Pt/C surface. Cyclic voltammogram analysis demonstrates a noteworthy increase in the oxidation pre-peak at 0.5 V for FJHM-Pt/C compared to Pt/C BASF. When employing pure H2 as fuel, the single proton exchange membrane fuel cell (PEMFC) utilizing Pt/C BASF as the anode catalyst exhibits a higher maximum power density (MPD) than its FJHM-Pt/C counterpart. Conversely, in the presence of CO, the PEMFC with FJHM-Pt/C as the catalyst demonstrates a superior MPD compared to the cell equipped with commercial Pt/C as the anode. These findings underscore enhanced CO tolerance, highlighting the potential advantages of the FJHM preparation method.
Conversão de metano em metanol em camada fina de difusão de gás utilizando fotocatalisadores porosos de trióxido de tungstênio e titânia
2023 - YOVANOVICH, M.; SOUZA, R.F.B. de; OLIVEIRA NETO, A.; LAZAR, D.R.R.
A conversão de metano a metanol representa atualmente uma importante alternativa para o controle das mudanças climáticas no planeta, uma vez que o gás carbônico e o metano são os principais gases de geração de efeito estufa na atmosfera terrestre. A fotocatálise heterogênea tem sido apresentada na literatura como uma rota promissora para conversão de metano a metanol pois possibilita que a reação seja conduzida à temperatura e pressão ambiente. Na presente pesquisa foram estudados fotocatalisadores constituídos por dióxido de titânio (TiO2) e trióxido de tungstênio (WO3) nas composições atômicas (100:0, 95:5, 90:10, 85:15 e 80:20). A síntese foi realizada a partir de pó de óxido de titânio e de ácido tungstíco, via reação com solução de borohidreto de sódio. Uma fina camada de eletrocatalisador TiO2/WO3 foi depositada numa camada difusora de carbono, ambos acomodados numa superficie porosa de aço inoxidável, todos em forma de disco, formando o eletrodo de difusão gasosa (EDG). As atividades fotocatalíticas para conversão de metano a metanol dessas composições foram avaliadas a 25 oC e pressão ambiente nos reatores de fluxo descontínuo e contínuo em luz visível e ultravioleta. Os fotocatalisadores de TiO2/WO3, foram caracterizados por microscopia eletrônica de transmissão, difração de raios X (DRX), voltametria cíclica e espectroscopia Raman. A quantificação da conversão de metano/metanol foi obtida pelo método Boyaci com base nos resultados de espectroscopia Raman. A conversão de metano a metanol em ambos os reatores, contínuo e descontínuo, foi efetiva. No reator descontínuo, na condição de luz visível, o eletrocatalisador TiO2/WO3 de melhor performance foi o de composição atômica 90:10. Em condição de irradiação UV, a conversão metano a metanol também é observada, entretanto com a formação radial superóxido, que consome o metano e metanol produzido, e com a formação mais acentuda de de ácido fórmico e formaldeído, a taxa de conversão é reduzida. Em regime contínuo a conversão metano a metanol é mais eficiente em concentrações de 15 e 20 mol% de óxido de tungstênio. Este comportamento deve-se ao menor tempo de residência dos reagentes no sistema reacional. Em um sistema fotoeletrocatalítico, a conversão é intensificada.
Nickel supported on polymeric graphitic carbon nitride for electrocatalytic in reduction of carbon dioxide
2023 - BATISTA, WALKER V.F. do C.; COELHO, JESSICA F.; OLIVEIRA, WANESSA L. de; PEREIRA FILHO, NIVALDO G.; OLIVEIRA, EDUARDA F. de; CRUZ, TAIS dos S. da; SILVA, HIDILA S.T. da; MARQUES, GLEISON N.; MESQUITA, JOAO P. de; SOUZA, RODRIGO F.B. de; NETO, ALMIR O.
This study explores the potential of carbon-based materials, specifically CN-Ni-doped, as catalysts for CO2 reduction to methanol in a PEM-R. The research investigates the impact of Ni incorporation on CN's structure, resulting in increased interlayer spacing and reduced crystallite size. Additionally, the introduction of Ni modifies the samples' morphology, creating a more compact structure with smaller sheets. The findings indicate that CN-Ni displays promising catalytic activity, achieving a 25% Faradaic Efficiency (FE) with a methanol production rate of approximately 1.1 mol L−1 h−1. The study underscores the significance of optimizing reactor operational parameters to enhance CO2RR. In conclusion, this research contributes to the advancement of efficient and sustainable approaches for CO2 utilization and methanol synthesis.