Palladium-Based Nanocatalysts for Alcohol Electrooxidation in Alkaline Media
Direct alcohol alkaline fuel cells (DAAFCs) are potential power sources for a variety of portable applications as they provide unique advantages over hydrogen-based fuel cell devices. Alcohols (such as methanol, ethanol, ethylene glycol, and glycerol) hav
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Palladium-Based Nanocatalysts for Alcohol Electrooxidation in Alkaline Media Remegia Mmalewane Modibedi, Kenneth Ikechukwu Ozoemena, and Mkhulu Kenny Mathe
Abstract Direct alcohol alkaline fuel cells (DAAFCs) are potential power sources for a variety of portable applications as they provide unique advantages over hydrogen-based fuel cell devices. Alcohols (such as methanol, ethanol, ethylene glycol, and glycerol) have high volumetric energy density and are easier to store and transport than hydrogen. Palladium-based nanocatalysts have continued to receive much research attention because of their cost advantages, relative abundance, and unique properties in the electrocatalytic oxidation of alcohols in alkaline media compared to platinum catalysts. Recent efforts have focused on the discovery of palladium-based electrocatalysts with little or no platinum for oxygen reduction reaction (ORR). This chapter is an overview of the recent developments in the employment of palladium-based nanocatalysts, containing little or no platinum, for the electrooxidation of alcohols in alkaline media.
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Introduction
The research and development of nanostructured electrode materials for improved performance of the direct alcohol fuel cells (DAFCs) in alkaline electrolytes has continued to grow. Palladium-based nanocatalysts, in particular, have continued to receive much research attention because of their unique properties in alcohol electrooxidation in alkaline media compared to their platinum-based counterparts [1].
R.M. Modibedi • M.K. Mathe Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR), Meiring Naude Road, Brummeria, Pretoria 0001, South Africa K.I. Ozoemena (*) Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR), Meiring Naude Road, Brummeria, Pretoria 0001, South Africa Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa e-mail: [email protected] M. Shao (ed.), Electrocatalysis in Fuel Cells, Lecture Notes in Energy 9, DOI 10.1007/978-1-4471-4911-8_6, # Springer-Verlag London 2013
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Palladium is more abundant in nature and sells at half the current market price of platinum. Unlike Pt, the Pd-based electrocatalysts are more active towards the oxidation of a plethora of substrates in alkaline media. The high activity of Pd in alkaline media is advantageous considering that non-noble metals are sufficiently stable in alkaline for electrochemical applications. Importantly, it is believed that the integration of Pd with non-noble metals (as bimetallic or ternary catalysts) can remarkably reduce the cost of the membrane electrode assemblies (MEAs) and boost the widespread application or commercialization of DAFCs [1]. Palladium has proved to be a better catalyst for alcohol electrooxidation in alkaline electrolytes than Pt [2]. Palladium activity towards the electrooxidation of low-molecular weight alcohols can be enhanced by the presence of a second or third metal, either alloyed or in
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