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Electrocatalysis of Pt-Based Metal Loaded  TiO2 Modified Graphene Oxide for Methanol Oxidation

Category : Physical Science
Author : S. Rattanakansang , S. Themsirimongkon, B. Kantalue, B. Inceesungvorn, S. Saipanya, P. Waenkaew*
Email : paralee.w@gmail.com
Keyword : Electrocatalyst, Electrodeposition, Graphene oxide, Methanol oxidation, Metal oxide, Titaniumdioxide
Volume : Microsc. Microanal. Res. 2017 30(1)
DOI Number : 10.14456/microsc-microanal-res.2017.2
ISSN :
Download Start & End Page : 6 - 11


Abstract

Titanium dioxide (TiO2) modified graphene oxide (GO) was prepared as a support for methanol oxidation reaction. Electrodeposition of platinum (Pt) and palladium (Pd) on the obtained TiO2-GO was then carried out to study their activities on methanol oxidation. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy (EDS) were used to identify their morphologies and chemical compositions, respectively. It was found that, TiO2 was successfully attached on GO surface and a narrow size distribution of Pt particles was found on TiO2-GO surface. EDS spectrum confirmed the presence of C, O, Ti, and Pt elements in the prepared catalysts. The electrocatalytic activities of the electrocatalysts toward oxidation of 0.5 M CH3OH in 0.5 M H2SO4 solution were examined using cyclic voltammetry (CVs). For mono-metallic Pt catalysts, the addition of TiO2 significantly enhanced methanol oxidation property and promoted CO tolerance performance. With exceptional activity and durability toward efficient methanol oxidation reaction, the forward current intensity, backward current intensity and onset potential of the 2Pt/TiO2-GO are 1.36 mA.cm-2 and 0.98 mA.cm-2 and 0.44 V vs.Ag/AgCl, respectively. Long-term stabilities of theelectrocatalysts were examined by chronoamperometry (CAs). It was found that the 2Pt/TiO2-GO (0.019 mA.cm-2) showed higher current intensity than the 2Pt/GO catalyst (0.008 mA.cm-2). For bi-metallic xPt2Pd/TiO2-GO catalysts, their activities and stabilities are not outstanding but the 6Pt2Pd/TiO2-GO showed rather promising results in terms of lower potential and comparable current intensity to the 8Pt/TiO2-GO.Incorporation of Pd with Pt provided lower onset potential, lower potential at maximum current intensities (Ef) and higher stabilities compared with the catalysts without Pd.




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