The effect of antimony-tin and indium-tin oxide supports on the catalytic activity of Pt nanoparticles for ammonia electro-oxidation

Autor(es)

Silva, Julio Cesar M. ; Piasentin, Ricardo M. ; Spinace, Estevam V. ; Neto, Almir O. ; Baranova, Elena A.

• Tipo de documento: Artigo Científico
• Fonte: Materials Chemistry and Physics; v. 180, p. 97-103, SEP 1 2016.
• Citações Web of Science: 15

Resumo

Platinum nanoparticles supported on carbon (Pt/C) and carbon with addition of ITO (Pt/C-ITO (In2O3)(9)center dot(SnO2)(1)) and ATO (Pt/C-ATO (SnO2)(9).(Sb2O5)(1)) oxides were prepared by sodium borohydride reduction method and used for ammonia electro-oxidation reaction (AmER) in alkaline media. The effect of the supports on the catalytic activity of Pt for AmER was investigated using electrochemical (cyclic voltammetry and chronoamperometry) and direct ammonia fuel cell (DAFC) experiments. X-ray diffraction (XRD) showed Pt peaks attributed to the face-centered cubic (fcc) structure, as well as peaks characteristic of In2O3 in ITO support and cassiterite SnO2 phase of ATO support. According to transmission electron micrographs the mean particles sizes of Pt over carbon were 5.4, 4.9 and 4.7 nm for Pt/C, Pt/C-ATO and Pt/C-ITO, respectively. Pt/C-ITO catalysts showed the highest catalytic activity for ammonia electrooxidation in both electrochemical and fuel cell experiments. We attributed this to the presence of In2O3 phase in ITO, which provides oxygenated or hydroxide species at lower potentials resulting in the removal of poisonous intermediate, i.e., atomic nitrogen (N-ads) and promotion of ammonia electrooxidation. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/01577-0 - Desenvolvimento de materiais e estudos de degradação de eletrocatalisadores e suportes para ânodo de células a combustível alcalinas
• Beneficiário: Júlio César Martins da Silva
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 14/09868-6 - Reação de oxidação de amônia e determinação dos produtos de reação utilizando-se eletrocatalizadores e suportes com elevada durabilidade e alta atividade catalítica
• Beneficiário: Júlio César Martins da Silva
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado