RODRIGO FERNANDO BRAMBILLA DE SOUZA

RODRIGO FERNANDO BRAMBILLA DE SOUZA

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Electro-oxidation of ethanol in acid medium using carbon-supported PtRh nanoparticles with (100) preferential orientation
2021 - PEREIRA FILHO, N.G.; SOUZA, R.F.B.; RAMOS, A.S.; ANTONIASSI, R.M.; OLIVEIRA NETO, A.; SPINACE, E.V.
Carbon-supported PtRh nanoparticles with preferential (100) orientation was prepared by an alcohol-reduction process using KBr as a shape directing agent. The electrocatalysts were characterized by EDX (energy-dispersive X-ray analysis), XRD (X-ray diffraction) and TEM (Transmission electron microscopy). The electro-oxidation of ethanol was studied by cyclic voltammetry and chronoamperometry at room temperature in acid medium. On-line differential mass spectrometry experiments were performed on a single cell of a direct ethanol fuel cell (DEFC) at 60 0C and the anodic effluents were analyzed by ATR-FTIR. PtRh/C (100) electrocatalyst showed cubic-like morphology and average nanoparticles size of 8 nm and provided superior DEFC performance (density power per Pt active area) and CO2 selectivity compared to polycrystalline PtRh/C and commercial Pt/C electrocatalysts.
Conversion of methane to methanol using WO3/TiO2 porous photocatalyst
2021 - 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.
Activation of methane on PdZn/C electrocatalysts in an acidic electrolyte at low temperatures
2019 - NANDENHA, J.; NAGAHAMA, I.H.F.; YAMASHITA, J.Y.; FONTES, E.H.; AYOUB, J.M.S.; SOUZA, R.F.B. de; FONSECA, F.C.; NETO, A.O.
PdZn/C electrocatalysts were prepared by sodium borohydride utilized as reducing agent for activation methane in an acidic medium at room temperature and in a proton exchange membrane fuel cell (PEMFC) at 80°C. The materials prepared were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The diffractograms of the PdZn/C electrocatalysts showed only peaks associated with Pd face-centered cubic (fcc) structure. Cyclic voltammograms (CV) of all electrocatalysts after adsorption of methane shown an increment in current during the anodic scan, this effect was more pronounced for Pd(70)Zn(30)/C. In situ ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared) experiments was not observed the formation of intermediates adsorbed for PdZn/C electrocatalysts, this behavior indicated that the methane oxidation occurs by parallel mechanisms. Polarization curves at 80°C in PEMFC show that Pd(90)Zn(10)/C has superior performance over the other electrocatalysts in methane oxidation.
PtBi/C electrocatalysts for formic acid electro-oxidation in acid and alkaline electrolyte
2015 - YOVANOVICH, M.; PIASENTIN, R.M.; AYOUB, J.M.S.; NANDENHA, J.; FONTES, E.H.; SOUZA, R.F.B. de; BUZZO, G.S.; SILVA, J.C.M.; SPINACE, E.V.; ASSUMPCAO, M.H.M.T.; NETO, A.O.; SILVA, S.G. da
PdSn/C electrocatalysts with different atomic rations for ethanol electro-oxidation in alkaline media
2014 - SILVA, SIRLANE G. da; ASSUMPCAO, MONICA H.M.T.; SILVA, JULIO C.M.; SOUZA, RODRIGO F.B. de; SPINACE, ESTEVAM V.; OLIVEIRA NETO, ALMIR; BUZZO, GUILHERME S.
PdSn/C with different Pd:Sn atomic ratios (90:10, 80:20. 70:30, 60:40 and 50:50) were prepared by borohydride reduction and tested for ethanol electro-oxidation in alkaline media. X-ray diffractograms patterns of the obtained materials showed the characteristic peaks of face-centered cubic structure of Pd, however, the PdSn alloy formation was not observed for all electrocatalysts. Also, the peaks of metallic Sn or SnO2 phases were not clearly observed in the diffractograms suggesting the formation of amorphous phases. The electro-oxidation of ethanol was studied by cyclic voltammetry and chronoamperometry at room temperature and PdSn/C (50:50) showed the best performance in these conditions. PdSn/C (50:50) and (90:10) were tested in single fuel cell at 75oC and the highest power density was obtained with PdSn/C (90:10).
Electro-oxidation of formic acid on PdIr/C-Sbsub(2)Osub(5)-SnOsub(2) electrocatalysts prepared by borohydride reduction
2013 - NANDENHA, J.; SOUZA, R.F.B. de; ASSUMPCAO, M.H.M.T.; SPINACE, E.V.; OLIVEIRA NETO, A.
Ethanol electro-oxidation on PtSn/C-ATO electrocatalysts
2012 - AYOUB, J.M.S.; SOUZA, R.F.B. de; SILVA, J.C.M.; PIASENTIN, R.M.; SPINACE, E.V.; SANTOS, M.C.; OLIVEIRA NETO, A.
New Approaches for the ethanol oxidation reaction of Pt/C on carbon cloth using ATR-FTIR
2012 - SOUZA, R.F.B. de; SILVA, J.C.M.; SIMÕES, F.C.; CALEGARO, M.L.; NETO, A.O.; SANTOS, M.C.
Preparation of Pt/C-Insub(2)Osub(3).SnOsub(2) electrocatalysts by borohydride reduction process for ethanol electro-oxidation
2012 - HENRIQUE, R.S.; SOUZA, R.F.B. de; SILVA, J.C.M.; AYOUB, J.M.S.; PIASENTIN, R.M.; LINARDI, M.; SPINACE, E.V.; SANTOS, M.C.; NETO, A.O.
Electro-oxidation of ethanol of PtPdSn/C-Sbsub(2)Osub(5)-SnOsub(2) electrocatalysts prepared by borohydride reduction
2013 - PIASENTIN, R.M.; SOUZA, R.F.B. de; SILVA, J.C.M.; SPINACE, E.V.; SANTOS, M.C.; OLIVEIRA NETO, A.
Pt/C-Sb2O5.SnO2, PtPd/C-Sb2O5.SnO2 and PtPdSn/C-Sb2O5.SnO2 electrocatalysts were prepared in a single step using H2PtCl6.6H2O, Pd(NO3)2.2H2O and SnCl2.2H2O as metal sources, sodium borohydride as reducing agent and a physical mixture of 85% Vulcan Carbon XC72 and 15% Sb2O5.SnO2 (antimony tin oxide – ATO) as support. X-ray diffractograms showed that Pt-Pd-Sn(fcc) alloy, carbon and Sb2O5.SnO2 phases are present in the PtPdSn/C-Sb2O5.SnO2 electrocatalysts. Transmission electron microscopy for all electrocatalysts showed that the metal nanoparticles were homogeneously distributed over the supports with average particle sizes in the range of 3-5 nm. The electro-oxidation of ethanol was studied by cyclic voltammetry and chronoamperometry at 25oC and in a single Direct Ethanol Fuel Cell (DEFC) at 100oC. PtPdSn/C-Sb2O5.SnO2 electrocatalysts exhibited superior performance for ethanol electro-oxidation than PtPd/C-Sb2O5.SnO2 and Pt/C-Sb2O5.SnO2 electrocatalysts, respectively. In situ FTIR studies showed that acetic acid and CO2 are preferentially formed using PtPdSn/C-Sb2O5.SnO2 electrocatalysts.