Estudo comparativo da oxidação de metanol, etanol, propanol e butanol sobre eletrocatalisadores a base de platina, suportados em carbono
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Data
2017-11-27
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Universidade Federal de Goiás
Resumo
Nanoparticles of PtCu/C and PtSn/C with atomic composition of 3: 1 and Pt/C were
synthesized with 20% of metal mass using the reflux method of ethanol to reduce
metals and 80% of carbon mass Vulcan X 72-R of high surface area. The catalysts
obtained were characterized by X-ray diffraction, X-ray dispersive energy spectroscopy
and transmission electron microscopy. The results indicate that the nanoparticles have
sizes between 1.5 and 8.0 nm, regular forms, with little agglomeration, with peaks
related to the cubic face centered structure of Pt in all catalysts, peaks indicating the
formation of Sn in the Pt3Sn / C catalyst, with no peaks indicative of the formation of
Cu oxides in the Pt3Cu / C catalyst, bimetallic catalysts indicate the insertion of the less
noble metal in the Pt crystal lattice. Electrochemical characterization in acidic medium
indicates that all catalysts have electrocatalytic activities for the oxidation of primary
alcohols (C1 to C4) and 2-propanol, and the presence of the less noble metals
improves such activities, the Sn mainly by the electronic effect while the Cu by the
bifunctional effect. For methanol and 2-propanol the catalyst containing Cu has better
characteristics, alcohols with increase in the linear chain have the best catalyst
Pt3Sn/C. For all studied alcohols the oxidation mechanisms reveal diffusional
adsorption system characteristics with charge transfer reactions.
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Palavras-chave
Platina , Estanho , Cobre , Eletrocatalisadores , Eletrooxidação , Platinum , Tin , Copper , Electrocatalysts , Electrooxidation
Citação
REIS, R. G. C. S. Estudo comparativo da oxidação de metanol, etanol, propanol e butanol sobre eletrocatalisadores a base de platina, suportados em carbono. 2017. 102 f. Tese (Doutorado em Química) - Universidade Federal de Goiás, Goiânia, 2017.