Niobium as co-electrocatalyst for Pd in alkaline medium
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2018
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REUNIAO ANUAL DA SOCIEDADE BRASILEIRA DE QUIMICA: CONSTRUINDO O AMANHA, 41.
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Direct ethanol fuel cells (DEFC) have been evaluated as a possible alternative source of sustainable energy,
because it can reach high current densities with minimal pollutant production [1]. In this work, we report the
synthesis of PdxNby/C binary electrocatalysts supported on Vulcan XC-72 carbon by the sol-gel method [2].
These synthesized electrocatalysts were physically characterized by DRX, EDS, ICP-MS, XPS and TEM.
Their electrochemical activities (CV and CA) were evaluated as already reported by Souza [2]. Here, we
reported new results from Tafel plots and FTIR ex situ experiments for ethanol oxidation reaction using those
electrocatalysts. Pd/C electrocatalyst has the EOR governed by two
determining steps since it showed two straight lines
between 570 mV and 730mV, presenting also two different
slopes (a and b, in Figure 1). Unlike the other
electrocatalysts, with Nb in their chemical composition, that
the EOR occurs by one determining step since there is just
one slope. The exchange current densities (A cm-2) were
2.3x10-17, 2.7x10-12, 6.6x10-10, 3.6x10-11 and 7.3x10-11 for
Pd/Ca, Pd/Cb, Pd1Nb1/C, Pd3Nb1/C and Pd1Nb3/C,
respectively. This shows that Nb increases the electron
exchange rate at the analyte/electrode interface, improving
the kinetics of the EOR reaction [3]. FTIR experiments
strengthened the evidence that Nb modifies the Pd
mechanism for EOR electrocatalysis to a mechanism that
present almost no formation of acetaldehyde, avoiding the
reaction ... The FTIR spectra showed that Pd1Nb1/C displays the
highest production of CO2 and the lowest production of
acetaldehyde. Furthermore, the ADT experiments with ICP-MS analysis indicated that Pd1Nb1/C obtained the
highest peak current density during 1000 cycles of the experiment, presenting the lowest Pd mass loss after
the ADT.
Como referenciar
SOUZA, FELIPE M.; PARREIRA, LUANNA S.; OLIVEIRA, VITOR H.A.; PINHEIRO, VICTOR S.; BATISTA, BRUNO L.; NANDENHA, JULIO; NETO, ALMIR O.; SANTOS, MAURO C. Niobium as co-electrocatalyst for Pd in alkaline medium: improved selectivity and mechanism for ethanol electrooxidation reaction. In: REUNIAO ANUAL DA SOCIEDADE BRASILEIRA DE QUIMICA: CONSTRUINDO O AMANHA, 41., 21-24 de maio, 2018, Foz do Iguaçu, PR. Resumo... São Paulo: Sociedade Brasileira de Química, 2018. Disponível em: http://repositorio.ipen.br/handle/123456789/29720. Acesso em: 07 May 2024.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.