ARACELI JARDIM SILVA
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Artigo IPEN-doc 29680 Conversão de metano em metanol com co-geração de energia elétrica a partir de catalisadores de paládio suportados em carbono2023 - 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.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.