Fuels cell studies

Wakisaka M, Mitsui S, Hirose H, Kawashima K, Uchida H, Watanabe M. 2006. Electronic structures of Pt-Co and Pt-Ru alloys for CO-tolerant anode catalysts in polymer electrol3de fuel cells studied by EC-XPS. J Phys Chem B 110 23489-23496. 

Yahiro AT, Lee SM, Kimble DO. 1964. Bioelectrochemistry. I. Enzyme utilizing bio-fuel cell studies. Biochim Biophys Acta 88 375-383. 

Electroanalytical chemists and others are concerned not only with the application of new and classical techniques to analytical problems, but also with the fundamental theoretical principles upon which these techniques are based. Electroanalytical techniques are proving useful in such diverse fields as electro-organic synthesis, fuel cell studies, and radical ion formation, as well as with such problems as the kinetics and mechanisms of electrode reactions, and the effects of electrode surface phenomena, adsorption, and the electrical double layer on electrode reactions. 

The previous discussion has focused on the properties of perovskite materials rather than on their performance as anodes. The number of actual fuel-cell studies is more limited, but this literature has been reviewed recently by Irvine. Various perovskites have been investigated as potential SOFC anode materials however, these early efforts were hampered by low electrochemical activity toward methane oxidation,poor anode structure,or insufficient electrode conductivity. Most recently, Tao and Irvine demonstrated that an anode based on (Lao.75Sro.25)o.9Cro.5Mno.503 can provide reasonable power densities at 1173 K in 3% humidified CH4. Barnett and co-workers also reported stable power generation with methane and propane fuels on an anode based on LaCr03 however, they reported that the addition of Ni, in levels too small to affect the conductivity, was crucial in providing activity for the electrochemical oxidation reactions. 

The main advantage of the GDE technique is that the electrode structure is similar to the fuel cell membrane electrode assembly. Therefore, the obtained results may be closer to those tested in a real fuel cell. However, the GDE technique is still rarely used in fuel cell studies due to the complicated design of the electrochemical cell, as well as the instability and poor-repeatability of the results. Furthermore, prior to the electrochemical measurements, the GDE needs to... 

In recent years, EIS has been widely used in studies of electrochemical systems, including batteries and materials corrosion, and is also being increasingly employed by researchers in PEM fuel cell studies. During the last few decades this technique has emerged as a primary tool in PEM fuel cell diagnosis. 

Stevens, D. et ah, 64-Electrode PEM fuel cell studies of CO-tolerant hydrogen oxidation catalysts, ECS Trans., 3, 355, 2006. 

The anode catalyst should possess high electrochemical oxidation activity and minimal conventional oxidation activity the cathode catalysts should exhibit selectivity for the reduction of O2 to. Single chamber fuel cell studies using Ni-SDC as an anode and Smo.sSr 0.5C0O3 as a cathode showed that the anode catalyst was active for partial oxidation of C2H6 to produce CO and H2 for further electrochemical oxidation on the anode catalyst surface. 

Gode, P. Ihonen, J. Strandroth, A. Ericson, H. Lindbergh, G. Paronen, M. Sundholm, F. Sundhohm, G. Walsby, N. Membrane durability in a PEM fuel cell studied using PVDF based radiation grafted membranes. Fuel Cells 2003, 3 (1-2), 21-27. 

CARB Fuel Cell Study Is Unduly Pessimistic about Hydrogen for Cars, Conference Is Told, Hydrogen Fuel Cell Letter, March 1999. 

Comprehensive EXAFS reviews on catalysis have been recently published. These encompass studies concerning surface mediated electrochemical processes and catalytic solids under environmental conditions. The first set of studies examined the local structural changes in the metal occurring in tandem with redox processes under voltage control. " Recent work in this area examines the stability of bimetallic Pt-Ru electrodes and their performance in the hydrogen oxidation reaction in the presence of CO or direct methanol fuel cells. Studies reviewed involving supported metal catalysts concern, in the first place, the reduction process " while other studies also consider the oxidation process and reduction under inert gases. All of these studies make an attempt to understand the relevance of the metal support interface... 

Figure 14.20 Model solid oxide fuel cell studied using APXPS. (a) Schematic of the cell design. Solid oxide cells have a 200 nm Pt counter electrode, a 300 nm Au current collector on top of a 30 nm alumina film (black) and a 50, 100, or 250 nm ceria working electrode patterned onto a polycrystalline YSZ substrate. This geometry exposes all cell components to the X-ray beam. The drawing is not to scale, (b) During operation, the...

In order to get answers to these questions, the ability to better characterize catalysts and electrocatalysts in situ under actual reactor or cell operating conditions (i.e., operando conditions) with element specificity and surface sensitivity is crucial. However, there are very few techniques that lend themselves to the rigorous requirements in electrochemical and in particular fuel cell studies (Fig. 1). With respect to structure, in-situ X-ray diffraction (XRD) could be the method of choice, but it has severe limitations for very small particles. Fourier transform infra red (FTTR), " and optical sum frequency generation (SFG) directly reveal the adsorption sites of such probe molecules as CO," but cannot provide much information on the adsorption of 0 and OH. To follow both structure and adsorbates at once (i.e., with extended X-ray absorption fine stmcture (EXAFS) and X-ray absorption near edge stmc-ture (XANES), respectively), only X-ray absorption spectroscopy (XAS) has proven to be an appropriate technique. This statement is supported by the comparatively large number of in situ XAS studies that have been published during the last decade. 16,17,18,19,20,21,22,23,24,25 highly Versatile, since in situ measme-... 

Operando Fuel Cell Studies Hydrogen Oxidation in 100 ppm CO... 

Garsuch A, MacIntyre K, Michaud X, Stevens DA, Dahn JR (2008) Fuel cell studies on a nonnoble metal catalyst prepared by a template-assisted synthesis route. J Electrochem Soc 155 (9) B953-B957... 

The decrease of electrode activity with time observed in most organic oxidations is another problem for the development of fuel cells. Studies which have been reported indicate that electrodes can be activated by the application of suitable anodic pulses to the electrode. Activation by radioactive materials is being examined and shows promise, particularly for oxygen electrodes. Oxygen electrodes activated with radioactive T1 exhibited less polarization than inactivated electrodes. The use of photo- and sono-effects in this respect has also been suggested. 

Singlemicro solid oxide fuel cells study of anode and cathode materials in coplanar electrode design. Solid State Ionics, 181 (5-7), 332-337. 

This equation and its analogs have been widely used in fuel-cell studies (see, e.g., [23-26]). Equation (23.35) shows that the CL polarization voltage includes the ORR activation term (the first logarithm) and the transport polarization (the second logarithm). Note that the reaction order of the feed molecules appears as a factor at the transport logarithm. 

Three-dimensional model of a 50cm high temperature PEM fuel cell. Study of the flow channel geometry influence. Int.J. Hydrogen Energy, 35, 5510. 

Due to the ample potential of fuel cell commercialization using non-platinum alkaline membrane fuel cells, studies on anion exchange membranes for this technology are now an emerging field both in terms of research and development. 

Due to the ample potential of fuel cell commercialization using non-Pt alkaline membrane fuel cells, studies on anion exchange membranes for this technology are now an emerging field both in terms of research and development. Figure 1 shows the main research locations (both universities and companies) in which alkaline membrane fuel cell-related fields were or still are being developed [1]. More than 90 % of the indicated specific locations (denoted by yellow dots) focus on the development of anion exchange membranes. 

He Z, Mansfeld F (2009) Exploring the use of electrochemical impedance spectroscopy in microbial fuel cell studies. Energy Environ Sci 2 215-219... 

Polymer Electrolyte Fuel Cells, Mass T ransport, Fig. 5 Illustration of the downscaling possibilities for experimental fuel cell studies... 

In fuel cell studies, Eq. (1.24) can be simplified further if we take into account that the second exponent in (1.24) makes a noticeable contribution to the total rate Q only close to equilibrimn, when the rates of direct and reverse reactions are nearly the same. However, near equilibrium the oxygen and water concentrations are close to their reference values and hence the respective concentration factors in Eq. (1.24) are close to 1. 

The catalytic (supported or unsupported) interface in the vast majority of direct liquid fuel cell studies is realized in practice either as a catalyst coated membrane (CCM) or catalyst coated diffusion layer (CCDL). Both configurations in essence are part of the electrode design category, which is referred to as a gas diffusion electrode, characterized by a macroporous gas diffusion and distribution zone (thickness 100-300 pm) and a mainly mesoporous, thin reaction layer (thickness 5-50 pm). The various layers are typically hot pressed, forming the gas diffusion electrode-membrane assembly. Extensive experimental and mathematical modeling research has been performed on the gas diffusion electrode-membrane assembly, especially with respect to the H2-O2 fuel cell. It has been established fliat the catalyst utilization efficiency (defined as the electrochemically available surface area vs. total catalyst surface area measured by BET) in a typieal gas diffusion electrode is only between 10-50%, hence, flie fuel utilization eflfieieney can be low in such electrodes. Furthermore, the low fuel utilization efficiency contributes to an increased crossover rate through the membrane, which deteriorates the cathode performance. 

Research in electrocatalysis was strongly stimulated in the early 1960s by efforts toward the development of various types of fuel cells. Studies were initiated on the various factors influencing the rates not only of hydrogen evolution but also of other reactions, particularly cathodic oxygen reduction and the complete oxidation of simple organic substances ( fuels ) to carbon dioxide. The... 

A hierarchy of cell models is often represented as a chain of models of various dimensionality (from ID to 3D). This picture is inherited from fluid dynamics, where 3D models traditionally have been considered as being superior over ID or 2D models. However, in fuel cell studies, the situation is more complicated. 

It should be noted that a Ti02 slurry is usually made before spin coating or screen printing. Previous photocatal5ftic fuel cell studies showed that Ti02 slurry can be easily prepared by using... 

---