Synergistic enhancement of the electro-oxidation of methanol at tailor-designed nanoparticle-based CoOx/MnOx/Pt ternary catalysts

•A novel ternary nanoparticle-based electrode is fabricated for MOR.•The loading level and deposition sequence of each constituent are crucial for MOR.•CoOx/MnOx/Pt/GC electrode showed a superb catalysis for MOR.•Activity for MOR at CoOx/MnOx/Pt/GC electrode increases with pH. The current study addr...

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Bibliographic Details
Published in:Electrochimica acta 2015-05, Vol.165, p.402-409
Main Authors: El-Deab, Mohamed S., El-Nowihy, Ghada H., Mohammad, Ahmad M.
Format: Article
Language:English
Subjects:
Electrocatalysis
Methanol oxidation
PEM fuel cells
Platinum nanoparticles
Transition metal oxides
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Summary:•A novel ternary nanoparticle-based electrode is fabricated for MOR.•The loading level and deposition sequence of each constituent are crucial for MOR.•CoOx/MnOx/Pt/GC electrode showed a superb catalysis for MOR.•Activity for MOR at CoOx/MnOx/Pt/GC electrode increases with pH. The current study addresses the enhanced electroctrocatalytic activity of a nanoparticle-based ternary catalyst composed of Pt (nano-Pt), manganese oxide (nano-MnOx), and cobalt oxide (nano-CoOx) (all were assembled on a glassy carbon (GC) substrate) towards the direct methanol electro-oxidation reaction (MOR) in an alkaline medium. The electrocatalytic activity of the modified electrodes towards MOR depends on the loading level of nano-Pt, nano-MnOx, and nano-CoOx onto the GC electrode as well as the order of deposition of each component. Interestingly, the CoOx/MnOx/Pt/GC electrode (with nano-Pt firstly deposited onto the GC surface followed by nano-MnOx then nano-CoOx) shows the highest catalytic activity and stability towards MOR for a prolonged time of continuous electrolysis. This is revealed from the large increase (seven times) in the peak current of MOR at this electrode compared with that obtained at Pt/GC electrode. The influence of operating pH on the catalytic activity of the proposed catalyst is investigated. Several techniques including cyclic voltammetry, field-emission scanning electron microscopy and energy dispersive X-ray spectroscopy and X-ray diffraction are used to address the catalytic activity of the catalyst and to reveal its surface morphology and composition.
ISSN:0013-4686
1873-3859
DOI:10.1016/j.electacta.2015.02.231