RODRIGO FERNANDO BRAMBILLA DE SOUZA

RODRIGO FERNANDO BRAMBILLA DE SOUZA

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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.
Methane to methanol conversion using proton-exchange membrane fuel cells and PdAu/antimony-doped tin oxide nanomaterials
2023 - MAIA, VICTORIA A.; NANDENHA, JULIO; GONCALVES, MARLON H.; SOUZA, RODRIGO F.B. de; O.NETO, ALMIR
This study investigates the use of Au-doped Pd anodic electrocatalysts on ATO support for the conversion of methane to methanol. The study uses cyclic voltammetry, in situ Raman spectra, polarization curves, and FTIR analysis to determine the optimal composition of gold and palladium for enhancing the conversion process. The results demonstrate the potential for utilizing methane as a feedstock for producing sustainable energy sources. The Pd75Au25/ATO electrode exhibited the highest OCP value, and Pd50Au50/ATO had the highest methanol production value at a potential of 0.05 V. Therefore, it can be concluded that an optimal composition of gold and palladium exists to enhance the conversion of methane to methanol. The findings contribute to the development of efficient and sustainable energy sources, highlighting the importance of exploring alternative ways to produce methanol.
Graphene deposited on glass fiber using a non-thermal plasma system
2023 - GOMES, PAULO V.R.; BONIFACIO, RAFAEL N.; SILVA, BARBARA P.G.; FERREIRA, JOAO C.; SOUZA, RODRIGO F.B. de; OTUBO, LARISSA; LAZAR, DOLORES R.R.; NETO, ALMIR O.
This study reports a bottom-up approach for the conversion of cyclohexane into graphene nanoflakes, which were then deposited onto fiberglass using a non-thermal generator. The composite was characterized using transmission electron microscopy, which revealed the formation of stacked few-layer graphene with a partially disordered structure and a d-spacing of 0.358 nm between the layers. X-ray diffraction confirmed the observations from the TEM images. SEM images showed the agglomeration of carbonaceous material onto the fiberglass, which experienced some delamination due to the synthesis method. Raman spectroscopy indicated that the obtained graphene exhibited a predominance of defects in its structure. Additionally, atomic force microscopy (AFM) analyses revealed the formation of graphene layers with varying levels of porosity.
PdxNiy/TiO2 Electrocatalysts for Converting Methane to Methanol in An Electrolytic Polymeric Reactor - Fuel Cell Type (PER-FC)
2023 - COELHO, JESSICA F.; GUTIERREZ, ISABELY M.; PEREIRA FILHO, NIVALDO G.; ZAMBIAZI, PRISCILLA J.; OLIVEIRA NETO, ALMIR; SOUZA, RODRIGO F.B. de
PdxNiy/TiO2 bimetallic electrocatalysts were used in fuel cell polymeric electrolyte reactors (PER-FC) to convert methane into methanol through the partial oxidation of methane promoted by the activation of water at room temperature. X-ray diffraction measurements showed the presence of Pd and Ni phases and TiO2 anatase phase. TEM images revealed mean particle sizes larger than those reported for PdNi materials supported, indicating that TiO2 promotes particle aggregation on its surface. Information on the surface structure of electrocatalysts obtained by Raman spectra indicated the presence or formation of NiO. The PER-FC tests showed the highest power density for the electrocatalyst with the lowest amount of nickel Pd80Ni20/TiO2 (0.58 mW cm􀀀2). The quantification of methanol through the eluents collected from the reactor showed higher concentrations of methanol produced, revealing that the use of TiO2 as a support also increased the reaction rate.
Effective phosphate removal from water by electrochemically mediated precipitation with coffee grounds biocarbon obtained by non-thermal plasma method
2023 - SILVESTRIN, G.A.; GONCALVES, M.H.; GODOI, C.M.; MAIA, V.A.; FERREIRA, J.C.; GUILHEN, S.N.; NETO, A.O.; SOUZA, R.F.B. de
This study investigates the use of biocarbon electrodes, produced from coffee grounds through plasma pyrolysis, in the electrochemically mediated precipitation process for phosphorus removal in a flow reactor. The structural and electrochemical properties of biocarbon were analyzed using X-ray powder diffraction (XRD), Raman spectroscopy, and cyclic voltammetry. The results show that biocarbon consists of both graphene oxide and lignocellulose with surface OH groups that facilitate the breakdown of water, a key step in the electrochemically mediated precipitation process for phosphorus removal. The addition of graphite to the biocarbon paste was found to be necessary to obtain a response from the biocarbon in cyclic voltammetry. The Gr75BC25 electrode achieved higher phosphorus removal rates than other tested electrodes, particularly at low flows, due to the functional groups present in biocarbon enhancing the breakdown of water. However, electrodes with a greater amount of biocarbon exhibit lower rates of phosphorus removal and higher consumption of electrical power, which can be attributed to their higher electrical resistivity. Thus, to optimize its use, it is important to balance the benefits of increased phosphorus removal rates with the trade-off of increased energy consumption and decreased phosphorus removal at higher levels of biocarbon. The results suggest that biocarbon produced from coffee grounds by plasma pyrolysis has the potential to be used as an effective electrode material for electrochemically mediated precipitation processes.
Conversão de metano em metanol com co-geração de energia elétrica a partir de catalisadores de paládio suportados em carbono
2023 - SILVA, ARACELI J.; ZAMBIAZI, PRISCILLA J.; GOMES, PAULO V.R.; NANDENHA, JULIO; GODOI, CAMILA M.; SOUZA, RODRIGO F.B. de; NETO, ALMIR O.; AZEREDO, NATHALIA F.B.
The application of solid electrolyte reactors for methane oxidation and energy co-generation is attractive, especially with the use of catalysts synthesized from noble metals such as palladium. In this work, we prepared three different compositions of palladium on carbon support to evaluate the composition that had the greatest potential for energy generation. Catalysts in the proportions of 5, 10 and 20% of Pd/C were tested for the conversion of greenhouse gases into organic molecules of higher added value using electrochemical fuel cell solid electrolyte reactors. The focus of this work was the conversion of methane into methanol, using the fuel cell as a reactor and the commercial Pd/C as electrocatalyst. The electrocatalysts were tested at the anode, analyzed by infrared (IR) spectroscopy and their activities verified by experiments with rotating ring disk electrode (RRDE). Higher levels of palladium (Pd/C 20%) favored obtaining electrical power, and the intermediate composition (Pd/C 10%) showed a greater production of less oxidized compounds, such as methanol, in addition to generating electricity.
Desempenho eletrocatalítico de Pd/C e Pt/C para geração de energia a partir do extrato de cana-de-açúcar em célula a combustível de líquido direto
2023 - VILLARDI, BRUNO D.Q.; FILHO, NIVALDO G.P.; GOMES, PAULO V.R.; NANDENHA, JULIO; GODOI, CAMILA M.; TAGOMORI, THAIS L.; AZEREDO, NATHALIA; SOUZA, RODRIGO F.B. de; NETO, ALMIR O.; ZAMBIAZI, PRISCILLA J.
The processing of biomass to obtain fuels such as ethanol results in generating waste and polluting the environment. However, to meet energy demand and simultaneously reduce environmental pollution, fuel cells are promising devices for converting chemical compounds into electricity. Fuel cells can be powered by various types of liquids, including the sugars available in sugarcane extract, with high energy potential. Fuel cells employ the use of noble metals as electrocatalysts, such as Pt or Pd, to carry out the oxidation of these fuels. In this sense, this work reports the study of the oxidation of sugarcane extract in these different noble metals. The platinum catalyst was shown to be more active for the oxidation of sugars, resulting in a power density 10 times greater than Pd/C using a 50% diluted sugarcane extract solution, resulting in promising fuel cell systems. To produce ecologically correct electrical energy for the industry in general.
Synthesis microwave-assisted
2023 - MELO, A.D.; SILVA, J.P. da; NOBRE, F.X.; COSTA, S.; SALES JUNIOR, J.C.C.; ANGLADA-RIVERA, J.; GUERRERO, F.; PAULA, M.M. da S.; SOUZA, R.F.B. de; PENA-GARCIA R.; AGUILERA, L.; LEYET, Y.
In this work, the variation in the structural and electrical properties of lithium-doped sodium titanate, obtained from an ultrafast (15 min) microwave-assisted synthesis has been reported. X-ray diffraction and Rietveld analysis have been done to identify the present phases, their composition, and lattice parameters. Na2Ti3O7 was identified as the major phase, while Na2Ti6O13 was obtained as a secondary phase in all samples. The phase composition usually varies depending on the content of the doping element. In the sample with 0.5% lithium ions, an additional phase corresponding to NaLiTi3O7 appeared. The microstructure of the ceramic samples showed an increase in the grains size and the appearance of small particles on the surface of the grains. This effect becomes more evident for the samples with 0.5% Li. Finally, the electrical properties of the ceramic samples studied were favored with an increase in doping and σdc values of 1.94 × 10− 5 S cm− 1, 2.51 × 10− 5 S cm− 1, and 4.00 × 10− 5 S cm− 1 were determined for Na2 − xLixTi3O7 with x = 0.0%, 0.1%, 0.5% of Li+.
Conversion of nitrogen to ammonia using a Cu/C electrocatalyst in a polymeric electrolyte reactor
2023 - MAIA, VICTORIA A.; SANTOS, CAMILA M.G.; AZEREDO, NATHALIA F.B.; ZAMBIAZI, PRISCILLA J.; ANTOLINI, ERMETE; NETO, ALMIR O.; SOUZA, RODRIGO F.B. de
The electrochemical conversion of N2 to NH3 using a polymeric electrolyte reactor is a promising method to accelerate the green production of hydrogen carriers. On this basis, we report the efficiency of ammonia production by the nitrogen reduction reaction using a Cu/C catalyst in a polymeric electrolyte membrane reactor. The Cu/C catalyst was prepared by the NaBH4 reduction method and characterized by X-ray diffraction, transmission electron microscopy, cyclic voltammetry, and conversion experiments performed in a polymer electrolyte membrane fuel cell type reactor. The X-ray diffraction results showed the presence of CuO2 and carbon phases, while the TEM images showed a high agglomeration of copper nanoparticles on carbon. The onset potential of nitrogen reduction was near to the Cu (I) to Cu0 reduction peak. Mass spectroscopy was used to observe the production of N2H2 and NH3 and the consumption of N2. Maximum ammonia production was detected at 0.0 V with a NH3 yield rate of 38.4 µg h−1 cm−2 and a faradaic efficiency of 42.57 %.