PEM fuel cells catalysts

Bonnemann, H. et al., Nanoscopic Pt-bimetal colloids as precursors for PEM fuel cell catalysts., J. New Mater. Electrochem. Syst., 3, 199, 2000. 

In this chapter, we will focus on several imporfanf aspecfs of fhe PEM fuel cell catalyst layer, including the CL components and their corresponding fxmctions, the types of catalyst layers, and catalyst layer fabrication and optimization. 

In PEM fuel cells, catalyst activity and catalyst efficiency are still significant issues. Russell and Rose summarize fundamental work involving X-ray absorption spectroscopy on catalysts in low temperature fuel cell systems. These types of studies are very useful for developing a detailed understanding of the mechanisms of reactions at catalyst surfaces and could lead to the development of new improved efficient catalysts. Important in the development of fuel cell technology are mathematical models of engineering aspects of a fuel cell system. Wang writes about studies related to this topic. 

Abigail Rose was raised in Somerset, England. She obtained her B.Sc. degree in Chemistry from the University of Southampton in 1998. She remained at Southampton, obtaining an M.Phil. in 1999 under the supervsion of Jeremy Frey and a Ph.D. in Physical Chemistry in 2003 working with Andrea Russell. Her Ph.D. thesis work, funded by the EPSRC at Johnson Matthey, was on the applications of in situ EXAFS to the study of PEM fuel cell catalysts. Presently, she is working as a fuel cell scientist at DstI, Porton Down, a U.K. Ministry of Defence research laboratory. 

Mo alloys of Pt have also been shown to enhance the CO tolerance of PEM fuel cell catalysts.Two peaks are often observed in the CO stripping volta-mmograms for PtMo catalysts the first at approximately 0.4 V vs RHE and the second at approximately 0.75 V. The first has been attributed to enhanced oxygen transfer from Mo oxy-hydroxide species on the surface of the catalyst particles. XANES at the Mo K and Pt L3 edges has provided support for the presence of such oxy-hydroxide species. Mukerjee et have shown that the... 

Bezerra C, Zhang L, Liu H, Lee K, Marques A, Marques E, Wang H, Zhang J, (2007). A review of heat-treatment effects on activity and stability of PEM fuel cell catalysts for oxygen reduction reaction Journal of Power Sources 173 891-908 Blesl M, Fahl U, Ohl M, (2004). HochtemperaturbrennstofFzellen und deren Kostenentwicklung. BWK, 56 72-56... 

Figure 1.6. PEM fuel cell catalyst layer structure [13]. (Reproduced from Journal of Power Sources, 102, Costamagna P, Srinivasan S, Quantum jumps in the PEMFC science and technology from the 1960s to the year 2000 Part II. Engineering, technology development and application aspects, 253-69 2001, with permission from Elsevier.)...

Eikerling M, Malek K, Wang Q (2008) Catalyst layer modeling structtue, properties, and performance. In Zhang JJ (ed) PEM fuel cells catalysts and catalyst layers—fundamentals... 

Paik CH, Saloka GS, Graham GW (2007) Influence of cyclic operation on PEM fuel cell catalyst stability. Electrochem Solid-State Lett 10 B39-B42... 

Zhang Jiujun, editor. PEM fuel cell catalysts and catalyst... 

Bezerra CWB, et al. A review of heat-treatment effects on activity and stability of PEM fuel cell catalysts for oxygen reduction reaction.) Power Sources 2007 173(2) 89f-908. 

Senevirathne K, Neburchilov V, Alzate V, Baker R, Neagu R, Zhang J, et al. Nb-doped Ti02/carbon composite supports synthesized by ultrasonic spray pyrolysis for proton exchange membrane (PEM) fuel cell catalysts. / Power Sources 2012 220(0) l-9. 

Russell AE, TessiCT BC, Wise AM, Rose A, Price SWT, Richardson PW, Ball SC, Theobald B, Thranpsett D, Crabb EM (2011) In sim XAS studies of cme-shell PEM fuel cell catalysts the opportunities and challenges. ECS Trans 41(l) 55-67... 

Engelhard, M., Liu, )., Wang, Y., and lin, Y. (2009) The corrosion of PEM fuel cell catalyst supports and its implications for developing durable catalysts. Electrochim. Acta, 54, 3109-3114. 

Baturina OA, Aubuchon SR, Wynne KJ. Thermal stability in air of Pt/C catalysts and PEM fuel cell catalyst layers. Chem Mater 2006 18 1498-1504. 

He C, Desai S, Brown G, BoUepalU S. PEM fuel cell catalysts cosL performance, and diuability. The Electrochemical Society Interface 2005 FaU 41—4. 

For most PEM fuel cell catalysts, carbon black and other order carbon materials (such as carbon nanotubes) are usually used as support materials. These supports can give catalysts good electron conductivity, a very important feature in a fuel cell catalyst. Platinum and its alloys are popular active components, generally highly dispersed on the surface of support materials as micro- and nano-particles. Catalyst performance is related not only to the conductivity and supporting amounts of noble metals, but also, and more importantly, to the dispersion and composition of the active components. Because the hydrogen molecule is small and easily diffused in catalysts, in general the catalyst pore structure is not more important than the surface area. 

The TG of the thermal decomposition of PEM fuel cell catalyst layer consisting of 46% Pt/Vulcan XC72/Nafion ionomer in air is shown in Figure 10.27. The TG data of 46% Pt/Vulcan XC72 and Nafion are included in Figure 10.27 for reference. The TG curve for the catalyst layer shows three distinct mass loss regions. The second mass loss region can be attributed to the decomposition of... 

Nafion. The decomposition temperature for Nafion in air was 300 °C. The thermal decomposition temperature of Nafion in the catalyst layers was lowered by about 100 °C in the presence of Pt/C catalysts. This indicates that Pt also catalyzed the decomposition of Nafion in the PEM fuel cell catalyst layers. The third mass loss region is due to carbon oxidation. 

Recently, novel carbon nanostructure materials such as single-wall carbon nanohoms, carbon nanoftbers (CNFs) and carbon nanotubes (CNTs) have been proposed as promising support materials for PEM fuel cell catalysts [80]. The main reason for using CNTs as a support for Pt catalysts is to improve the... 

We also discussed the durability issues of PEM fuel cell catalysts which have been recently recognized as one of the major barriers to the commercialization of fuel cells [10]. To use carbon with a higher graphitization degree as support materials and to alloy Pt with other metals can improve the catalyst durability. Compared with carbon black, several research groups have reported that the use of CNTs can be promising in effectively reducing the carbon corrosion problem [213]. 

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