Fuel oxygen reduction reaction

A fuel cell consists of an ion-conducting membrane (electrolyte) and two porous catalyst layers (electrodes) in contact with the membrane on either side. The hydrogen oxidation reaction at the anode of the fuel cell yields electrons, which are transported through an external circuit to reach the cathode. At the cathode, electrons are consumed in the oxygen reduction reaction. The circuit is completed by permeation of ions through the 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. 

Fuel cell applications Manganese dioxide as a new cathode catalyst in microbial fuel cells [118] OMS-2 catalysts in proton exchange membrane fuel cell applications [119] An improved cathode for alkaline fuel cells [120] Nanostructured manganese oxide as a cathodic catalyst for enhanced oxygen reduction in a microbial fuel cell [121] Carbon-supported tetragonal MnOOH catalysts for oxygen reduction reaction in alkaline media [122]... 

Electrode A is called the anode because the anodic reaction is favored over the cathodic reaction. In a fuel cell, the anodic oxidation of H2 is favored. The corresponding reaction at the cathode, electrode B, is the cathodic oxygen reduction reaction,... 

One way to illustrate the effect of the EDL is to compare in situ electrochemical reactions with their equivalent UHV counterparts. Due to their roles in fuel cells, the methanol oxidation reaction and the oxygen reduction reaction are two such reactions for which numerous in situ and UHV experiments have been performed. 

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. 

Schmidt, T. J., Paulus, U. A., Gasteiger, H. A. and Behm, R. J. 2001. The oxygen reduction reaction on a Pt/carbon fuel cell catalyst in the presence of chloride anions. Journal of the Electroanalytical Society 508 41-47. 

The most important electrokinetic data pertinent to fuel cell models are the specific interfacial area in the catalyst layer, a, the exchange current density of the oxygen reduction reaction (ORR), io, and Tafel slope of ORR. The specific interfacial area is proportional to the catalyst loading and inversely proportional to the catalyst layer thickness. It is also a strong function of the catalyst layer fabrication methods and procedures. The exchange current density and Tafel slope of ORR have been well documented in refs 28—31. 

The literature reviewed in sections 2—6 represents significant advances made in the last 20 years in our understanding of solid oxide fuel-cell cathodes. At the same time, however, this work has also underscored how complex the oxygen reduction reaction is, mak-... 

Water vapour is produced at the anode diluting the fuel. The hydrogen oxidation reaction (HOR) and the oxygen reduction reaction (ORR) occur at the triple phase boundary (TPB) zone where the electrode (electronic phase), electrolyte (ionic... 

This method is well suited for slightly soluble electroactive materials. It has been widely used for the study of oxygen reduction reaction and hydrogen oxidation reaction, the two main reactions occurring in fuel cells. 

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. 

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