Banca de QUALIFICAÇÃO: VICTOR DOS SANTOS PINHEIRO
Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.DISCENTE : VICTOR DOS SANTOS PINHEIRO
DATA : 09/11/2020
HORA: 14:00
LOCAL: por participação remota
TÍTULO:
Sn-containing electrocatalysts with a reduced amount of palladium for alkaline direct ethanol fuel cell applications
PÁGINAS: 42
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Físico-Química
ESPECIALIDADE: Eletroquímica
RESUMO:
Ethanol has gained prominence as fuel for the so-called direct ethanol fuel cells (DEFC) due to the use of biomass and has a low toxicity, and high energy density. In this work we synthesized and characterized hybrid electrocatalysts based on Pd and Sn nanoparticles supported on Vulcan XC-72 carbon black (PdxSny/Vulcan XC-72) with a reduced amount of Pd and evaluated their electrocatalytic activity for ethanol oxidation reaction (EOR) in alkaline direct ethanol fuel cells (ADEFCs) under different operating conditions. The electrocatalysts were synthesized in different Pd:Sn mass ratios (1:3, 1:1, 3:1 and 1:0) on the carbon support containing 20 wt % of metal. The electrocatalysts were characterized using X-ray diffraction, energy dispersive spectroscopy, inductively coupled plasma mass spectrometry, transmission electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The XRD patterns of the hybrid electrocatalysts revealed an alloy formation between Pd and Sn, and the electrocatalysts with lowest amount of Pd (Pd1Sn3/Vulcan XC-72) and highest electrochemically active surface area (ECSA) presented best performance in ADEFC experiments with a maximum current density and power density of 152 mA cm-2 and 42 mW cm-2, respectively. Beside the current density three times higher than that of the pure Pd catalyst, the open circuit potential of 939 mV at an operation temperature of 80 °C yielded the higher carbonate production. This behavior can be attributed to the presence of oxophilic Sn species, which improve the ability to remove adsorbed CO from active sites of the electrocatalysts. Oxygenated species, vacancies and defects detected in the structure of PdxSny/Vulcan XC-72 catalysts are accounted for their high activity, making them very promising for the application in ADEFC.
MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1544381 - MAURO COELHO DOS SANTOS
Membro Titular - Examinador(a) Interno ao Programa - 1844792 - AMEDEA BAROZZI SEABRA
Membro Titular - Examinador(a) Externo à Instituição - CHRISTIANE DE ARRUDA RODRIGUES - UNIFESP
Membro Suplente - Examinador(a) Interno ao Programa - 2351974 - JULIANA DOS SANTOS DE SOUZA
Membro Suplente - Examinador(a) Externo à Instituição - THIAGO REGIS LONGO CESAR DA PAIXAO - USP