Estudo comparativo da oxidação de metanol, etanol, propanol e butanol sobre eletrocatalisadores a base de platina, suportados em carbono

• Autor(a) principal: Reis, Renan Gustavo Coelho de Souza dos
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/0013000003ct1
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/8052
• topic: Platina; Estanho; Cobre; Eletrocatalisadores; Eletrooxidação; Platinum; Tin; Copper; Electrocatalysts; Electrooxidation; FISICO-QUIMICA::ELETROQUIMICA

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.