ARACELI JARDIM SILVA
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Artigo IPEN-doc 28849 Application of binary PdSb/C as an anode in a polymeric electrolyte reactor-fuel cell type for electrosynthesis of methanol from methane2022 - GODOI, CAMILA M.; SANTOS, MONIQUE C.L.; NUNES, LIVIA C.; SILVA, ARACELI J.; RAMOS, ANDREZZA S.; SOUZA, RODRIGO F.B. de; NETO, ALMIR O.PdSb catalyst prepared in different compositions were applied as an anode in a polymeric electrolyte reactor - fuel cell type (PER-FC) to convert methane into oxygenated products and energy in mild conditions. The PER-FC polarization curves for Pd90Sb10/C presented maximum current density about 0.92 mW cm-2 about 15% higher than PdSb materials. However, the material Pd50Sb50/C showed higher reaction rate for methanol generation than the other materials occurring close to the OCV (r ~ 7 mol L-1 h-1). The qualitative analyses of PER-FC effluent by FT-IR identified products as methanol, carbonate and formate ions from the partial oxidation of methane for all materials.Artigo IPEN-doc 28325 Conversion of methane to methanol using WO3/TiO2 porous photocatalyst2021 - YOVANOVICH, MARCOS; SILVA, ARACELI J. da; SOUZA, RODRIGO F.B. de; USSUI, VALTER; NETO OLIVEIRA, ALMIR; LAZAR, DOLORES R.R.The conversion of methane into methanol is one of the great challenges in the photocatalysis. In this investigation WO3/TiO2 photocatalysts was synthesized by sodium borohydride (NaBH4) method. The tungsten concentration was studied in the range of 5 to 20 atomic ratio. XRD results revealed a TiO2 anatase phase and WO3 peaks near the background noise. However, WO3 presence has been highlighted by Raman spectroscopy, indicating the existence of both orthorhombic and amorphous phase.The photocatalyst experiments showed that all materials enable the methanol production in UVC irradiation, and only the materials with WO3 content produced the alcohol in white light irradiation. The high conversion was observed for WO3(10)/TiO2(90) with 3.5 mmol h-1. The conversion of methane to methanol was most promising using WO3(10)/TiO2(90) due high conversion and no other products observed in FTIR spectra.Artigo IPEN-doc 27709 Methane conversion to higher value‑added product and energy co‑generation using anodes OF PdCu/C in a solid electrolyte reactor2021 - GODOI, C.M.; SANTOS, M.C.L.; SILVA, A.J.; TAGOMORI, T.L.; RAMOS, A.S.; SOUZA, R.F.B. de; OLIVEIRA NETO, A.PdxCuy/C catalysts combinations were employed to CH4 partial oxidation in mild condition using a solid electrolyte reactor—alkaline fuel cell type. The differential mass spectroscopy on line method was used to monitor the oxidation products obtained as methanol, dimethyl ether, methyl formate and potassium formate. It was observed that as the electrical potential of the reactor increases, the generation of products decreases. The best results for conversion of methane into methanol and energy co-generation was obtained from Pd90Cu10/ C and Pd50Cu50/ C due to better H2O activation effects and adsorption site for CH4 oxidation.Artigo IPEN-doc 27246 Conversion of methane into methanol using the [6,6′-(2,2′-bipyridine-6,6′-diyl)bis(1,3,5-triazine-2,4-diamine)](nitrato-O)copper(II) complex in a solid electrolyte reactor fuel cell type2020 - GARCIA, LUIS M.S.; RAJAK, SANIL; CHAIR, KHAOULA; GODOY, CAMILA M.; SILVA, ARACELI J.; GOMES, PAULO V.R.; SANCHES, EDGAR A.; RAMOS, ANDREZZA S.; SOUZA, RODRIGO F.B. de; DUONG, ADAM; NETO, ALMIR O.The application of solid electrolyte reactors for methane oxidation to co-generation of power and chemicals could be interesting, mainly with the use of materials that could come from renewable sources and abundant metals, such as the [6,6′- (2, 2′-bipyridine-6, 6′-diyl)bis (1,3,5- triazine-2, 4-diamine)](nitrate-O)copper (II) complex. In this study, we investigated the optimal ratio between this complex and carbon to obtain a stable, conductive, and functional reagent diffusion electrode. The most active Cu-complex compositions were 2.5 and 5% carbon, which were measured with higher values of open circuit and electric current, in addition to the higher methanol production with reaction rates of 1.85 mol L−1 h−1 close to the short circuit potential and 1.65 mol L−1 h−1 close to the open circuit potential, respectively. This activity was attributed to the ability of these compositions to activate water due to better distribution of the Cu complex in the carbon matrix as observed in the rotating ring disk electrode experiments.