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.
In situ ATR-FTIR studies of ethanol electro-oxidation in alkaline medium on PtRh/C electrocatalyst prepared by an alcohol reduction process
2016 - FONTES, E.H.; SILVA, SIRLANE G. da; SPINACE, E.V.; NETO, A.O.; SOUZA, R.F.B. de
Anion exchange membrane fuel cell is a new chance to produce a functional and portable fuel cell; however, the studies are still at an early stage with few reports regarding the AEMFC. PtRh/C electrocatalysts with different Pt:Rh atomic ratios were prepared by an alcohol reduction process. X-ray diffraction patterns for all PtRh/C materials indicated no shift in Pt(fcc) peaks showing that Rh did not incorporated into Pt lattice; however, the analysis of lattice parameter showed that some Pt atoms are added to Rh(fcc) structure. The mean particle sizes were in the range of 4–5 nm. Electrochemical experiments showed that PtRh/C electrocatalyst with Pt:Rh atomic ratio of 70:30 had superior performance exhibiting a current density of 5.0 mA mgmetal−1 . From in situ ATR-FTIR experiments, it was observed that PtRh/C electrocatalyst with Pt:Rh atomic ratio of 70:30 produced more acetate ions than other ones, while the material prepared with Pt:Rh atomic ratio of 50:50 was more selective to CO2 as observed in acid media.
Estudo da oxidação eletroquímica do ácido fórmico em meio alcalino utilizando eletrocatalisadores Pd/C-Sbsub(2)Osub(5)-SnOsub(2) PdAuIr/C-Sbsub(2)Osub(5)SnOsub(2)
2015 - NANDENHA, J.; SOUZA, R.F.B.; SPINACE, E.V.; NETO, A.O.
Oxidação eletroquímica de etanol em meio alcalino utilizando eletrocatalisadores PtSnAu/C, PtSnRh/C e quaternário PtSnAuRh/C
2015 - DUTRA, R.M.; SOUZA, R.F.B.; SPINACE, E.V.; NETO, A.O.
Electrochemical and in situ ATR-FTIR studies of ethanol electro-oxidation in alkaline medium using PtRh/C electrocatalysts
2015 - FONTES, E.H.; PIASENTIN, R.M.; AYOUB, J.M.S.; SILVA, J.C.M. da; ASSUMPCAO, M.H.M.T.; SPINACE, E.V.; NETO, A.O.; SOUZA, R.F.B. de
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
PtAu/C electrocatalysts as anodes for direct ammonia fuel cell
2015 - SILVA, JULIO C.M.; SILVA, SIRLANE G. da; SOUZA, RODRIGO F.B. de; BUZZO, GUILHERME S.; SPINACE, ESTEVAM V.; OLIVEIRA NETO, ALMIR; ASSUMPCAO, MONICA H.M.T.
PtAu/C electrocatalysts prepared by borohydride reduction method with different Pt:Au atomic ratios (50:50 and 70:30) were tested as work electrodes/anodes in electrochemical experiments and also using a direct ammonia fuel cell (DAFC). X-ray diffraction patterns showed the formation of PtAu alloy while transmission electron micrographs showed the particles sizes between 5.8 and 6.4 nm. PtAu/C 70:30 presented the best results showing a current density about 20% higher when compared to Pt/C in voltammetry experiments and a power density about 60% higher than Pt/C using DAFC, while Au/C showed practically no activity in both experiments. The best results obtained with PtAu/C (70:30) could be explained by the electronic effect (PtAu alloy) associated with adsorbed hydroxyl species (AuOHads) and also the lower Au-N energy adsorption.
Oxidation of ammonia using PtRh/C electrocatalysts: fuel cell and electrochemical evaluation
2015 - ASSUMPCAO, MONICA H.M.T.; PIASENTIN, RICARDO M.; HAMMER, PETER; SOUZA, RODRIGO F.B. de; BUZZO, GUILHERME S.; SANTOS, MAURO C.; SPINACE, ESTEVAM V.; OLIVEIRA NETO, ALMIR; SILVA, JULIO C.M. da
This study reports on the use of PtRh/C electrocatalysts prepared by the borohydride reduction method with different Pt:Rh atomic ratios: (90:10, 70:30 and 50:50) which was investigated toward the ammonia electro-oxidation considering electrochemical and also direct ammonia fuel cell (DAFC) experiments. The DAFC experiments were conducted using different proportions of NH4OH and KOH as fuels. X-ray diffraction showed the formation of PtRh alloy while transmission electron micrographs showed the particles sizes between 4.1 and 4.5 nm. Among the different NH4OH and KOH concentrations the combination of 3 mol L−1 NH4OH and 3 mol L−1 KOH was the most favorable due to the higher KOH concentration, which increased the electrolyte conductivity, thus, improving the ammonia oxidation. Moreover, among the PtRh/C electrocatalysts the Pt:Rh ratio of 90:10 showed to be the best suited one since it showed a power density almost 60% higher than Pt. X-ray photoelectron spectroscopy results revealed for this catalyst that the nanoparticles contain a high proportion of metallic Pt and Rh phases, supporting the alloy formation between Pt and Rh. The improved fuel cell efficiency can be related to the combination of different effects: the alloy formation between Pt and Rh (electronic effect), suppressing the adsorption strength of poisonous intermediates, and a synergic effect between Pt and Rh at this composition.
Enhanced electrooxidation of ethanol using Pd/C+TiOsub(2) electrocatalysts in akaline media
2015 - SILVA, J.C.M.; BUZZO, G.S.; SOUZA, R.F.B. de; SPINACE, E.V.; NETO, A.O.; ASSUMPCAO, M.H.M.T.
Synthesis of hydroquinone with co-generation of electricity from phenol aqueous solution in a proton exchange membrane fuel cell reactor
2015 - BUZZO, G.S.; RODRIGUES, A.C.B.; SOUZA, R.F.B. de; SILVA, J.C.M.; BASTOS, E.L.; SPINACE, E.V.; NETO, A.O.; ASSUMPCAO, M.H.M.T.
In a proton exchange membrane fuel cell (PEMFC) an aqueous solution containing 100 mg L−1 of phenol was oxidized at the anode using PtRu/C as catalyst while oxygen gas was reduced at cathode using Pt/C as catalyst. The use of a fuel cell as a flow reactor allowed obtaining hydroquinone, an important compound much used in medicine and cosmetic industry, as product with the co-generation of electricity. A conversion of 20% of phenol with the formation of 16 mg L−1 of hydroquinone (80% of selectivity) was observed after 240 min of fuel cell operation at 80 °C.