Metals fuel cell oxygen reduction catalysts

Non-precious metal oxygen reduction catalysts for PEM fuel cells 338... 

He, P, M. Lefevre, G. Faubert, and J.P. Dodelet (1999). Oxygen reduction catalysts for polymer electrolyte fuel cells from the pyrolysis of various transition metal acetates adsorbed on 3,4,9,10-perylenetetracarboxyhc dianhydride. J. New Mat. Electrochem. Systems 2, 243-251. 

Platinum has a myriad of practical uses, especially in the field of electrochemistry where it is used as a catalyst and as a reference electrode. In particular, platinum is the most active known pure metal for the oxygen reduction reaction (ORR) in which O2 is split and combined with protons to form H2O. This is an important step in low-temperature fuel cells (polymer electrolyte fuel cells, direct methanol fuel cells, etc.) as it often is what limits the total fuel cell efficiency. Furthermore, platinum is rather expensive with the materials cost of its use in fuel cells being roughly half of the total fuel cell cost. Consequently, a great deal of effort is made in order to optimize its use. 

Wood TE, Tan Z, Schmoeckel AK, O Neill D, Atanasoski R (2008) Non-precious metal oxygen reduction catalyst for PEM fuel cells based on nitroaniline precursor. J Power Sources 178(2) 510-516... 

Liu G, Li XG, Ganesan P, Popov BN (2009) Development of non-precious metal oxygen-reduction catalysts for PEM fuel cells based rai N-doped ordered porous carbon. Appl Catal B Environ 93(1-2) 156-165... 

Kobayashi M, Niwa H, Harada Y, Horiba K, Oshima M, Ofuchi H, Terakura K, Ikeda T, Koshigoe Y, Ozaki JI, Miyata S, Ueda S, Yamashita Y, Yosikawa H, Kobayashi K (2011) Role of residual transition metal atoms in oxygen reduction reaction in cobalt phthalocyanine-based carbon cathode catalysts for polymer electrolyte fuel cell. J Power Sources 196 8346-8351... 

However, for technical use of AFC, the long-term behavior of AFC components is important, especially that of the electrodes. Nickel can be used for the hydrogen oxidation reaction (catalyst in the anode) and on the cathode silver can be used as catalyst (see next section), no expensive noble metal (platinum) is necessary, because the oxygen reduction reaction kinetics are more rapid in alkaline electrolytes than in acids and the alkaline electrochanical environment in AFC is less corrosive compared to acid fuel cell conditions. Both catalysts and electrolyte represents a big cost advantage. The advantages of AFC are not restricted only to the cheaper components, as shown by Giilzow [1996]. 

Matter PH, Biddinger EJ, Ozkan US (2007) Nonprecious metal oxygen reduction catalysts for PEM fuel cells. Catalysis 20 338-366... 

In spite of the success in the optimization of platinum catalysts, a major breakthrough in the field of fuel cells is yet to be achieved. Especially, the desire for a significant cost reduction by the replacement of platinum motivates international research activities investigating new catalyst concepts for cathodes. Thereby, the cathodes have to be sufficiently stable under fuel cell conditions the alternative non-noble metal catalysts (NNMC) need to have a high selectivity for direct reduction of oxygen to water. The US department of energy (DOE) defined 25% of the achievable current density of a commercial platinum catalyst as target value for 2015. For fuel cell application, the catalysts should be producible in such a nano-structured form that suitable gas diffusion structures can be built. 

This is a major reason why the majority of non-noble metal catalysis research has focused on the cathode part of the fuel cell system this work began about 1964 with a paper in Nature by Jasinski indicating that N4-metal chelates had electrochemical oxygen reduction capacity, and specifically with the discovery that C0N4 phthalocyanine is an oxygen reduction catalyst in alkaline solution [102,... 

F. Jaouen, E. Proietti, M. Lefevre, R. Chenitz, J.-P. Dodelet, G. Wu, et al.. Recent advances in non-predous metal catalysis for oxygen-reduction reaction in polymer electrolyte fuel cells. Energy Environ. Sd. 4 (2011) 114-130. R. Jasinski, A new fuel cell cathode catalyst. Nature 201 (1964) 1212-1213. 

Conversely, the oxygen reduction reaction (ORR) has also been widely studied, in particular for its requirement in proton exchange membrane (PEM) fuel cells. Platinum based catalysts are typically used to increase the sluggish kinetics, although other noble metal catalysts and carbon... 

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