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Bio-butanol as fuel for direct alcohol fuel cells - investigation of Sn modified Pt catalyst for butanol electro-oxidation

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posted on 26.05.2016 by V.K. Puthiyapura, Daniel J.L. Brett, A.E. Russell, Wen-Feng Lin, Christopher Hardacre
Direct alcohol fuel cells (DAFCs) mostly use low molecular weight alcohols such as methanol and ethanol as fuels. However, short-chain alcohol molecules have a relative high membrane crossover rate in DAFCs and a low energy density. Long chain alcohols such as butanol have a higher energy density as well as a lower membrane crossover rate compared to methanol and ethanol. Although a significant number of studies have been dedicated to low molecular weight alcohols in DAFCs, very few studies are available for longer chain alcohols such as butanol. A significant development in the production of bio-butanol and its proposed application as an alternative fuel to gasoline in the last decade makes butanol an interesting candidate fuel for fuel cells. Different butanol isomers were compared in this study on various Pt and PtSn bimetallic catalysts for their electro-oxidation activities in acidic media. Clear distinctive behaviours were observed for each of the different butanol isomers using cyclic voltammetry (CV), indicating a difference in activity and the mechanism of oxidation. The voltammograms of both n-butanol and iso-butanol showed similar characteristic features, indicating a similar reaction mechanism; whereas 2-butanol showed completely different features; for example, it did not show any indication of poisoning. Ter-butanol was found to be inactive for oxidation on Pt. In-situ FTIR and CV analysis showed that OHads was essential for the oxidation of primary butanol isomers which only forms at high potentials on Pt. In order to enhance the water oxidation and produce OHads at lower potentials, Pt was modified by the oxophilic metal Sn and the bimetallic PtSn was studied for the oxidation of butanol isomers. A significant enhancement in the oxidation of the 1o butanol isomers was observed on addition of Sn to the Pt, resulting in an oxidation peak at a potential ~520 mV lower than that found on pure Pt. The higher activity of PtSn was attributed to the bi-functional mechanism on PtSn catalyst. The positive influence of Sn was also confirmed in the PtSn nanoparticle catalyst prepared by the modification of commercial Pt/C nanoparticle and a higher activity was observed for PtSn (3:1) composition. The temperature-dependent data showed that the activation energy for butanol oxidation reaction over PtSn/C is lower than that over Pt/C.

Funding

This paper was funded by EPSRC (Grant no: EP/K014706/1).

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Chemical Engineering

Published in

ACS applied materials & interfaces

Citation

PUTHIYAPURA, V.K. ... et al., 2016. Bio-butanol as fuel for direct alcohol fuel cells - investigation of Sn modified Pt catalyst for butanol electro-oxidation. ACS Applied Materials & Interfaces, 8(20), pp.12859–12870.

Publisher

© American Chemical Society

Version

VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by/4.0/

Publication date

2016

Notes

This is an ACS AuthorChoice open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.

ISSN

1944-8244

eISSN

1944-8252

Language

en

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