Activity and stability studies of titanates and titanate-carbon nanotubes supported Ag anode catalysts for direct methanol fuel cell
Journal of Power Sources 304 (2016) 255-265 • 2016
Publication Information
Authors
Mohamed Mokhtar Mohamed*, M. Khairy, Salah Eid
Keywords
Ag/titanate-SWCNT
Direct methanol fuel cells
Electrocatalysis
Electrochemical impedance
Electrical conductivity
Journal
Journal of Power Sources 304 (2016) 255-265
Publisher
Elsevier
Volume
304
Issue
Not Available
Pages
255-265
publication.type
International
Paper Link
Not Available
Supplementary Materials
Not Available
Abstract
Titanate-SWCNT; synthesized via exploiting the interaction between TiO2 anatase with oxygen functionalized
SWCNT, supported Ag nanoparticles and Ag/titanate are characterized using XRD, TEM-EDXSAED,
N2 adsorption, Photoluminescence, Raman and FTIR spectroscopy. These samples are tested for
methanol electrooxidation via using cyclic voltammetry (CV) and impedance measurements. It is shown
that Ag/titanate nanotubes exhibited superior electrocatalytic performance for methanol oxidation
(4.2 mA cm2) than titanate-SWCNT, Ag/titanate-SWCNT and titanate. This study reveals the existence of
a strong metal-support interaction in Ag/titanate as explored via formation of TieOeAg bond at
896 cm1 and increasing surface area and pore volume (103 m2 g1, 0.21 cm3 g1) compared to Ag/
titanate-SWCNT (71 m2 g1, 0.175 cm3 g1) that suffers perturbation and defects following incorporation
of SWCNT and Ag. Embedding Ag preferably in SWCNT rather than titanate in Ag/titanate-SWCNT
disturbs the electron transfer compared to Ag/titanate. Charge transfer resistance depicted from
Nyquist impedance plots is found in the order of titanate > Ag/titanate-SWCNT > titanate-SWCNT > Ag/
titanate. Accordingly, Ag/titanate indicates a slower current degradation over time compared to rest of
catalysts. Conductivity measurements indicate that it follows the order Ag/titanate > Ag/titanate-
SWCNT > titanate > titanate-SWCNT declaring that SWCNT affects seriously the conductivity of Ag(titanate)
due to perturbations caused in titanate and sinking of electrons committed by Ago through
SWCNT.
SWCNT, supported Ag nanoparticles and Ag/titanate are characterized using XRD, TEM-EDXSAED,
N2 adsorption, Photoluminescence, Raman and FTIR spectroscopy. These samples are tested for
methanol electrooxidation via using cyclic voltammetry (CV) and impedance measurements. It is shown
that Ag/titanate nanotubes exhibited superior electrocatalytic performance for methanol oxidation
(4.2 mA cm2) than titanate-SWCNT, Ag/titanate-SWCNT and titanate. This study reveals the existence of
a strong metal-support interaction in Ag/titanate as explored via formation of TieOeAg bond at
896 cm1 and increasing surface area and pore volume (103 m2 g1, 0.21 cm3 g1) compared to Ag/
titanate-SWCNT (71 m2 g1, 0.175 cm3 g1) that suffers perturbation and defects following incorporation
of SWCNT and Ag. Embedding Ag preferably in SWCNT rather than titanate in Ag/titanate-SWCNT
disturbs the electron transfer compared to Ag/titanate. Charge transfer resistance depicted from
Nyquist impedance plots is found in the order of titanate > Ag/titanate-SWCNT > titanate-SWCNT > Ag/
titanate. Accordingly, Ag/titanate indicates a slower current degradation over time compared to rest of
catalysts. Conductivity measurements indicate that it follows the order Ag/titanate > Ag/titanate-
SWCNT > titanate > titanate-SWCNT declaring that SWCNT affects seriously the conductivity of Ag(titanate)
due to perturbations caused in titanate and sinking of electrons committed by Ago through
SWCNT.
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