Fuel-cells, electrocatalyst for

MaiUard F, Lu GQ, Wieckowski A, Stimnting U. 2005. Ru-decorated Pt surfaces as model fuel cell electrocatalysts for CO electrooxidation. J Phys Chem B 109 16230-16243. 

Strasser, P., Fan, Q., Devenney, M., Weinberg, W. H., Combinatorial Exploration of ternary fuel cell electrocatalysts for DMFC anodes — a comparative study of PtRuCo, PtRuNi and PtRuW systems, AIChE fall meeting, 2003, San Francisco. 

Electro-catalysts which have various metal contents have been applied to the polymer electrolyte membrane fuel cell(PEMFC). For the PEMFCs, Pt based noble metals have been widely used. In case the pure hydrogen is supplied as anode fuel, the platinum only electrocatalysts show the best activity in PEMFC. But the severe activity degradation can occur even by ppm level CO containing fuels, i.e. hydrocarbon reformates[l-3]. To enhance the resistivity to the CO poison of electro-catalysts, various kinds of alloy catalysts have been suggested. Among them, Pt-Ru alloy catalyst has been considered one of the best catalyst in the aspect of CO tolerance[l-3]. 

The change in the electronic properties of Ru particles upon modification with Se was investigated recently by electrochemical nuclear magnetic resonance (EC-NMR) and XPS [28]. In this work, it was established for the first time that Se, which is a p-type semiconductor in elemental form, becomes metallic when interacting with Ru, due to charge transfer from Ru to Se. On the basis of this and previous results, the authors emphasized that the combination of two or more elements to induce electronic alterations on a major catalytic component, as exemplified by Se addition on Ru, is quite a promising method to design stable and potent fuel cell electrocatalysts. 

This chapter presents the design and application of a two-stage combinatorial and high-throughput screening electrochemical workflow for the development of new fuel cell electrocatalysts. First, a brief description of combinatorial methodologies in electrocatalysis is presented. Then, the primary and secondary electrochemical workflows are described in detail. Finally, a case study on ternary methanol oxidation catalysts for DMFC anodes illustrates the application of the workflow to fuel cell research. 

Three techniques have been described in the literature to prepare combinatorial libraries of fuel cell electrocatalysts solution-based methods [8, 10-14], electrodeposition methods [15-17] and thin film, vacuum deposition methods [18-21]. Vacuum deposition methods were chosen herein for electrocatalyst libraries in order to focus on the intrinsic activity of the materials, e.g., for ordered or disordered single-phase, metal alloys. 

The complete primary screening workflow for the discovery of new fuel cell electrocatalysts is shown in Fig. 11.8. The individual components of this workflow are designed such that no bottleneck occurs. 

Phosphoric Acid Fuel Cells (PAFCs) for Utilities Electrocatalyst Crystallite Design, Carbon Support, and Matrix Materials Challenges... 

In chapter 4, Stonehart (a major authority in the field of H2 fuelcell technology and its fundamental aspects) writes, with co-author Wheeler, on the topic of Phosphoric Acid Fuel-Cells (PAFCs) for Utilities Electrocatalyst Crystallite Design, Carbon Support, and Matrix Materials Challenges. This contribution reviews, in detail, recent information on the behavior of very small Pt and other alloy electrocatalyst crystallites used as the electrode materials for phosphoric acid electrolyte fuel-cells. 

Lambert reviews the role of alkali additives on metal films and nanoparticles in electrochemical and chemical behavior modihcations. Metal-support interactions is the subject of the chapter by Arico and coauthors for applications in low temperature fuel cell electrocatalysts, and Haruta and Tsubota look at the structure and size effect of supported noble metal catalysts in low temperature CO oxidation. Promotion of catalytic activity and the importance of spillover are discussed by Vayenas and coworkers in a very interesting chapter, followed by Verykios s examination of support effects and catalytic performance of nanoparticles. In situ infrared spectroscopy studies of platinum group metals at the electrode-electrolyte interface are reviewed by Sun. Watanabe discusses the design of electrocatalysts for fuel cells, and Coq and Figueras address the question of particle size and support effects on catalytic properties of metallic and bimetallic catalysts. 

Metal-support interactions in fuel cell electrocatalysts, with particular emphasis for methanol oxidation and oxygen reduction, are discussed. The interaction of the... 

P. Stonehart and D. Wheeler, Phosphoric Acid Fuel Cells (PAFCs) for vehicles Electrocatalyst Crystalite Design, Carbon Support, and Matrix Materials Challenges in Modem Aspects of Electrochemistry, Vol. 38, Ed. by B. E. Conway, Kluwer/Plenum, New York (2005) Chapter 4, 385. 

Electrocatalyst selection and design are the key aspects of PEM fuel cells. The most popular catalyst is platinum for the anode and the cathode in pure hydrogen cells. For direct methanol fuel cells and for hydrogen cells with carbon monoxide present, a platinum/ruthenium alloy is used. 

Carbon Materials as Supports for Fuel Cell Electrocatalysts... 

CARBON MATERIALS AS SUPPORTS FOR FUEL CELL ELECTROCATALYSTS... 

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