Electrocatalysts Oxygen reduction reaction

Wu J, Zhang J, Peng Z, Yang S, Wagner FT, Yang H. Truncated octahedral PtsNi oxygen reduction reaction electrocatalysts. / Am Chem Soc 2010 132(14) 4984-5. 

Ma S, Goenaga GA, Call AV, Liu D-J (2011) Cobalt imidazolate framework as precursor for oxygen reduction reaction electrocatalysts. Chem Eur J 17 2063-2067... 

Lin, C.-L., Sanchez-Sanchez, C.M., Bard, A.J. Methanol tolerance of Pd-Co oxygen reduction reaction electrocatalysts using scanning electrochemical microscopy. Electrochem. Solid State Lett. 2008, 11, B136-B139. 

Lee JW, Popov BN (2007) Ruthenium-based electrocatalysts for oxygen reduction reaction—a review. J Solid State Electrochem 11 1355-1364... 

Lee K, Zhang L, Zhang J (2007) Ternary non-noble mefal chalcogenide (W-Co-Se) as electrocatalyst for oxygen reduction reaction. Electrochem Commun 9 1704-1708... 

Gochi-Ponce Y, Alonso-Nunez G, Alonso-Vante N (2006) Synthesis and electrochemical characterization of a novel platinum chalcogenide electrocatalyst with an enhanced tolerance to methanol in the oxygen reduction reaction. Electrochem Commun 8 1487-1491... 

In this section, we summarize the kinetic behavior of the oxygen reduction reaction (ORR), mainly on platinum electrodes since this metal is the most active electrocatalyst for this reaction in an acidic medium. The discussion will, however, be restricted to the characteristics of this reaction in DMFCs because of the possible presence in the cathode compartment of methanol, which can cross over the proton exchange membrane. 

Raghuveer V, Manthiram A, Bard AJ. 2005. Pd-Co-Mo electrocatalyst for the oxygen reduction reaction in proton exchange membrane fuel cells. J Phys Chem B 109 22909-22912. 

Shao M, Liu P, Zhang J, Adzic RR. 2007a. Origin of enhanced activity in palladium alloy electrocatalysts for oxygen reduction reaction. J Phys Chem Bill 6772-6775. 

Wang W, Zheng D, Du C, Zou Z, Zhang X, Xia B, Yang H, Akins DL. 2007. Carbon-supported Pd-Co bimetallic nanoparticles as electrocatalysts for the oxygen reduction reaction. J Power Sources 167 243-249. 

Polyaniline (PANI) was investigated as electrocatalyst for the oxygen reduction reaction in the acidic and neutral solutions. Galvanostatic discharge tests and cyclic voltammetry of catalytic electrodes based on polyaniline in oxygen-saturated electrolytes indicate that polyaniline catalyzes two-electron reduction of molecular oxygen to H2O2 and HO2". 

Carbon is unique among chemical elements since it exists in different forms and microtextures transforming it into a very attractive material that is widely used in a broad range of electrochemical applications. Carbon exists in various allotropic forms due to its valency, with the most well-known being carbon black, diamond, fullerenes, graphene and carbon nanotubes. This review is divided into four sections. In the first two sections the structure, electronic and electrochemical properties of carbon are presented along with their applications. The last two sections deal with the use of carbon in polymer electrolyte fuel cells (PEFCs) as catalyst support and oxygen reduction reaction (ORR) electrocatalyst. 

In practice, in all fuel cells that involve the utilization of 02 from air (Section 13.4.5), the oxygen reduction reaction [Eqs. (13.4) and (13.24)] is always rate determining for terrestrial applications. One can seejust how important it is to attempt to develop electrocatalysts for the cathodes of fuel cells on which the enhanced current density is high and Tafel slope is low and the efficiency of energy conversion, therefore, maximal. The direct relation of the mechanism of oxygen reduction and the associated Tafel parameters to the economics of electricity production and transportation is thus clearly seen. 

Mani P, Srivastava R, Strasser P. Dealloyed binary PtM3 (M = Cu, Co, Ni) and ternary PtNbM (M = Cu, Co, Fe, Cr) electrocatalysts for the oxygen reduction reaction performance in polymer electrolyte membrane fuel cells. J Power Sources. 2011 196 666-73. 

In this section, we review approaches to predicting dissolution potentials in 6.1. Next we discuss the hydrogen evolution reaction and studies to understand it and predict new electrocatalysts in 6.2. Electrochemical oxidation reactions that are typical in fuel cells are discussed in 6.3. Finally, the studies on the increasingly important oxygen reduction reaction are reviewed in 6.4. 

In this chapter we review studies, primarily from our laboratory, of Pt and Pt-bimetallic nanoparticle electrocatalysts for the oxygen reduction reaction (ORR) and the electrochemical oxidation of H2 (HOR) and H2/CO mixtures in aqueous electrolytes at 274—333 K. We focus on the study of both the structure sensitivity of the reactions as gleaned from studies of the bulk (bi) metallic surfaces and the resultant crystallite size effect expected or observed when the catalyst is of nanoscale dimension. Physical characterization of the nanoparticles by high-resolution transmission electron microscopy (HRTEM) techniques is shown to be an essential tool for these studies. Comparison with well-characterized model surfaces have revealed only a few nanoparticle anomalies, although the number of bimetallics... 

Electrocatalysts One of the positive features of the supported electrocatalyst is that stable particle sizes in PAFCs and PEMFCs of the order of 2-3 nm can be achieved. These particles are in contact with the electrolyte, and since mass transport of the reactants occurs by spherical diffusion of low concentrations of the fuel-cell reactants (hydrogen and oxygen) through the electrolyte to the ultrafine electrocatalyst particles, the problems connected with diffusional limiting currents are minimized. There has to be good contact between the electrocatalyst particles and the carbon support to minimize ohmic losses and between the supported electrocatalysts and the electrolyte for the proton transport to the electrocatalyst particles and for the subsequent oxygen reduction reaction. This electrolyte network, in contact with the supported electrocatalyst in the active layer of the electrodes, has to be continuous up to the interface of the active layer with the electrolyte layer to minimize ohmic losses. 

Development of supported Pt electrocatalysts came as a result of intensive research on fundamental and applied aspects of electrocatalysis [especially for kinetically difficult oxygen reduction reaction (ORR)] fueled by attempts at commercialization of medium-temperature phosphoric acid fuel cells (PAFCs) in the late 1960s and early 1970s. Dispersion of metal crystallites in a conductive carbon support resulted in significant improvements in all three polarization zones (activation, ohmic, and... 

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