THENNER SILVA RODRIGUES

THENNER SILVA RODRIGUES

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Synthesis and characterization of catalysts based on nickel, cerium, and lanthanum supported on biocarbon for ethanol steam reforming
2018 - FERREIRA, J.C.; CAVALLARI, R.V.; LIMA, N.B.; RODRIGUES, T.S.; BERGAMASCHI, V.S.; SILVA, F.A. e
Ethanol steam reforming (ESR) is considered asa promising alternative for hydrogen production due to some differentadvantages that include the large availability, relatively low cost, andsuperior reactivity of ethanol as compared to other compounds. Thus, thistechnology is also considered more sustainable and greener as compared to othermethods usually employed for hydrogen production. However, the currentindustrial catalysts suffer from strong deactivation because the extensivecarbon deposition, which limits their performances and utilization. In order toovercome this limitation, we report herein the synthesis of a catalyst based onnickel, cerium and lanthanum supported on activated biocarbon by a microwaveassisted hydrothermal method. In this method, we first performed a hydrothermalactivation of the biocarbon support at 120 °C using nitric acid (0.3 M) in areactor coupled to a microwave source aiming the formation of acid groups atthe surface of our carbonaceous matrix. In a next step, the adsorption of La3+,Ce3+, and Ni3+ onto the activated biocarbon was performed by the addition ofLa(NO3)3.6H2O, Ce(NO3)3.6H2O, and Ni(NO3)3.6H2O in the suspension containingthe activated biocarbon and potassium thiosulfate for stabilization (pH 8.0) at75 °C. The obtained catalyst was then characterized by scanning electronmicroscopy, X-ray dispersive spectroscopy, X-ray diffraction, temperatureprogramed reduction, and surface area by the BET method. After this step, the catalystwas then evaluated towards the ESR, in which 100 % of ethanol conversion wasobserved with the formation of only H2 (~ 60%) and CO2 (ESR products) and COand CH4 as byproducts (both in low concentrations), indicating a goodselectivity for ESR. Good stability was also achieved with no significant lossof activity even after 24 hours of reaction at 550 °C. The reactants and thereaction products were analyzed by gas chromatograph (Agilent 7890A), equippedwith a thermal conductivity detector (TCD) and a flame ionization detector(FID) connected in series.
Preparação de catalisadores de níquel e cério suportados em carvão de coco
2018 - FERREIRA, JOAO C.; CAVALLARI, ROGER V.; SILVA, FELIPE A. e; RODRIGUES, THENNER S.; SILVA, JULIO C.M.; BERGAMASCHI, VANDERLEI S.
O carvão de coco foi ativado pelo processo hidrotermal assistido por microondas (HMO) usando ácido nítrico (2,42 M) nas condições de temperatura de 120 ºC, patamar de 45 minutos, rampa de aquecimento de 10 ºC min-1 e pressão de 3,0 kgf / cm2. Na caracterização usaram-se métodos analíticos como: espectroscopia Raman, medidas de área superficial (BET), análise térmica (TG), difração de raios X (DRX), microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva (EDS) e redução à temperatura programada (TPR). Os catalisadores foram avaliados na reforma a vapor do etanol objetivando a formação de hidrogênio. Foram observadas boas atividades catalíticas com conversão completa do etanol e formação predominante de produtos de reforma (H2 e CO2) e CO e CH4 como subprodutos e em baixas concentrações, indicando uma boa seletividade e estabilidade para a reação de reforma a vapor do etanol com a manutenção total de atividade mesmo após 24 horas de reação a 550 °C.
Synthesis and characterization of catalysts based on nickel, cerium, and lanthanum supported on biocarbon for ethanol steam reforming
2018 - FERREIRA, J.C.; CAVALLARI, R.V.; SILVA, F.A. e; RODRIGUES, T.S.; BERGAMASCHI, V.S.
Ethanol steam reforming (ESR) is considered asa promising alternative for hydrogen production due to some differentadvantages that include the large availability, relatively low cost, andsuperior reactivity of ethanol as compared to other compounds. Thus, thistechnology is also considered more sustainable and greener as compared to othermethods usually employed for hydrogen production. However, the currentindustrial catalysts suffer from strong deactivation because the extensivecarbon deposition, which limits their performances and utilization. In order toovercome this limitation, we report herein the synthesis of a catalyst based onnickel, cerium and lanthanum supported on activated biocarbon by a microwaveassisted hydrothermal method. In this method, we first performed a hydrothermalactivation of the biocarbon support at 120 °C using nitric acid (0.3 M) in areactor coupled to a microwave source aiming the formation of acid groups atthe surface of our carbonaceous matrix. In a next step, the adsorption of La3+,Ce3+, and Ni3+ onto the activated biocarbon was performed by the addition ofLa(NO3)3.6H2O, Ce(NO3)3.6H2O, and Ni(NO3)3.6H2O in the suspension containingthe activated biocarbon and potassium thiosulfate for stabilization (pH 8.0) at75 °C. The obtained catalyst was then characterized by scanning electronmicroscopy, X-ray dispersive spectroscopy, X-ray diffraction, temperatureprogramed reduction, and surface area by the BET method. After this step, the catalystwas then evaluated towards the ESR, in which 100 % of ethanol conversion wasobserved with the formation of only H2 (~ 60%) and CO2 (ESR products) and COand CH4 as byproducts (both in low concentrations), indicating a goodselectivity for ESR. Good stability was also achieved with no significant lossof activity even after 24 hours of reaction at 550 °C. The reactants and thereaction products were analyzed by gas chromatograph (Agilent 7890A), equippedwith a thermal conductivity detector (TCD) and a flame ionization detector(FID) connected in series.
Ni supported Ce0.9Sm0.1O2-δ nanowires
2019 - RODRIGUES, THENNER S.; MOURA, ARTHUR B.L. de; SILVA, FELIPE A. e; CANDIDO, EDUARDO G.; SILVA, ANDERSON G.M. da; OLIVEIRA, DANIELA C. de; QUIROZ, JHON; CAMARGO, PEDRO H.C.; BERGAMASCHI, VANDERLEI S.; FERREIRA, JOAO C.; LINARDI, MARCELO; FONSECA, FABIO C.
We reported herein the synthesis in high yields (> 97%) of Ce0.9Sm0.1O2-δ nanowires displaying well-defined shape, size, and composition by a simple, fast, and low-cost two-step hydrothermal method. The Ce0.9Sm0.1O2-δ nanowires synthesis was followed by the wet impregnation of Ni without the utilization of any stabilizing agent. The Ni/Ce0.9Sm0.1O2-δ nanowires showed higher surface area, high concentration of oxygen vacancies at surface, and finely dispersed Ni particles with significantly higher metallic surface area as compared with catalysts prepared from commercial materials with similar compositions. Such unique and improved properties are reflected on the catalytic performance of the Ni/Ce0.9Sm0.1O2-δ nanowires towards ethanol steam reforming. The nanowires exhibited high yields for hydrogen production (∼60% of selectivity) and an exceptional stability with no loss of activity after 192 h of reaction at 550 °C. The reported results provide insights and can inspire highyield production of nanostructured catalysts displaying controlled and superior properties that enable practical applications in heterogeneous catalysis.
Hardwired for success
2017 - RODRIGUES, THENNER S.; MOURA, ARTHUR B.; SILVA, FELIPE A. e; CANDIDO, EDUARDO G.; BERGAMASCHI, VANDERLEI S.; FERREIRA, JOAO C.; LINARDI, MARCELO; FONSECA, FABIO C.
CeO2-based nanomaterials have been extensively employed in catalysis and industry, showing excellent performances towards a variety of applications. In the past few decades, great developments have been reported associating the properties of nanostructured CeO2 with its catalytic performances. Thus, an intense research in this field have been performed in order to increasingly improve the performances of these nanomaterials such as the precise control over their structures, morphologies, compositions, among others. We propose herein, the synthesis of a novel well-defined Sm2O3-doped CeO2 nanowires decorated with nickel nanoparticles as a novel catalyst with outstanding performance towards ethanol steam reforming (ESR). In order to address these challenges, we were inspired by a well-established hydrothermal method for the synthesis of CeO2 nanowires. Herein, through simple modifications in the original protocol allowed us the obtaining in high yield (97%) extremely well-defined CeO2-Sm2O3 nanowires exhibiting uniform distributions in lengths and diameters. XRD results (Figure 1A) suggested the introduction of Sm species into the CeO2 crystal lattices, in which the quantitative Sm3+(aq) conversion achieved 10 mol%, as corroborated by ICP-OES analysis. The resulting CeO2-Sm2O3 nanowires were then employed as support for the Ni incorporation (1 wt%) by a wet impregnation approach, and the obtained catalyst (Figure 1B) was evaluated towards the ESR displaying an exceptional stability even after 100 hours of process at 550 °C. More specifically, 100 % of ethanol conversion was observed with the formation of only H2 and CO2 (ESR products) and CO and CH4 as byproducts (both in low concentrations), indicating a good selectivity for ESR compared to the most recent literature. The characterization data for the Ni/CeO2-Sm2O3 nanowires after catalytic experiment (Figure 1C) indicated that, even after 100 hours at 550 °C, no loss of shape was observed as well as no carbon structures formation justifying the exceptional observed stability.