Effects of catalyst load in Pt and Pb-based catalysts using formic acid oxidation as a model
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
23/10/2013
23/10/2013
2012
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Resumo |
In this paper, we discuss the effects of catalyst load with respect to carbon powder for several Pt and Pb-based catalysts, using formic acid as a model molecule. The discussion is based on electrochemical tests, a complete morphological investigation and theoretical calculations. We show that the Pt and Pb-based catalysts presented activity in formic acid oxidation at very low catalyst loads (e.g., 0.5% in respect to the carbon content). Physical characterisations demonstrate that the electrodes are composed of separated phases of Pt and lead distributed in Pt nanometric-sized islands that are heterogeneously dispersed on the carbon support and Pb ultra-small particles homogeneously distributed throughout the entire carbon surface, as demonstrated by the microscopy studies. At high catalyst loads, very large clusters of Pb(x)O(y) could be observed. Electrochemical tests indicated an increase in the apparent resistance of the system (by a factor of 19.7 Omega) when the catalyst load was increased. The effect of lead in the materials was also studied by theoretical calculations (OFT). The main conclusion is that the presence of Pb atoms in the catalyst can improve the adsorption of formic acid in the catalytic system compared with a pure Pt-based catalyst. (C) 2011 Elsevier B.V. All rights reserved. FAPESP FAPESP [2007/05155-1, 2007/05370-0] CNPq [472476/2008-4, 301863/2008-3, 483452/2010-6] CNPq CAPES CAPES UFABC UFABC LMELNLS (JEOL JEM 2100 TEMMSC) LME-LNLS (JEOL JEM 2100 TEM-MSC) DIMATINMETRO (FEI TITAN 80300 STEM) DIMAT-INMETRO (FEI TITAN 80-300 STEM) |
Identificador |
JOURNAL OF POWER SOURCES, AMSTERDAM, v. 199, n. 1, supl. 1, Part 1, pp. 75-84, FEB 1, 2012 0378-7753 http://www.producao.usp.br/handle/BDPI/35751 10.1016/j.jpowsour.2011.10.044 |
Idioma(s) |
eng |
Publicador |
ELSEVIER SCIENCE BV AMSTERDAM |
Relação |
JOURNAL OF POWER SOURCES |
Direitos |
closedAccess Copyright ELSEVIER SCIENCE BV |
Palavras-Chave | #LEAD-BASED CATALYSTS #FORMIC ACID OXIDATION #HAADF-STEM #XEDS-SI #DFT #DIPPED ADCLUSTER MODEL #FUEL-CELL APPLICATIONS #ELECTROCATALYTIC ACTIVITY #DENSITY FUNCTIONALS #METHANOL #NANOPARTICLES #REDUCTION #ELECTROOXIDATION #ADSORPTION #STABILITY #ELECTROCHEMISTRY #ENERGY & FUELS |
Tipo |
article original article publishedVersion |