Anodes fabrications

In electrolytic processes, the anode is the positive terminal through which electrons pass from the electrolyte. Anode design and selection of anode materials of constmction have traditionally been the result of an optimisation of anode cost and operating economics, in addition to being dependent on the requirements of the process. Most materials used in metal anode fabrication are characteristically expensive use has, however, been justified by enhanced performance and reduced operating cost. An additional consideration that has had increasing influence on selection of the appropriate anode is concern for the environment (see Electrochemical processing). 

Misono T, Murat, K, Fukui T, Chaichanawong J, Sato K, Abe H et al. Ni-SDC cermet anode fabricated from NiO-SDC composite powder for intermediate temperature SOFC. J. Power Sources 2006 157 754—757. 

Fig. 5.4 Illustrative drawing of a three-electrode electrochemical cell in which the Ti samples are anodized. Fabrication variables include temperature, voltage, pH and electrolyte composition.

In addition to oxidation losses-by the above four mechanisms, mechanical carbon loss (dusting) also occurs due to uneven oxidation of the anode surface. Furthermore, a variety of other factors, related to anode fabrication and use, can affect carbon consumption. The most important of these factors are (1) raw material quality,... 

The objective of making good anode carbon, which has the property values already specified, involves four important operations which are applied differently for Soderberg and prebake anode fabrication. These four operations are (1) filler aggregate sizing (2) paste pitching level determination, (3) paste compaction, and (4) compacted composite baking. 

Applying PEVD to Composite Anode Fabrication for Solid Oxide Fuel Cells... 

Precious metals are used for impressed current anodes because they are highly efficient electrodes and can handle much higher currents than anodes fabricated from other materials. Precious metal anodes are actually platinized titanium or niobium anodes the platinum is either clad or electroplated on the substrate. 

Tungsten carbide based non-Pt electrocatalyst have been evaluated for single cell performance of PEMFC. The power densities of WC/C (1 mg/cm ) and Ni-WC/C (1 mg/cm ) anodes fabricated by TPRe were 6.5 and 8.9 mW/cm, respectively, cathode of 20 wt% Pt and membrane of Naflon 117 (151). W2C (0.48 mg/cm ) anode catalyst was prepared by ball-milling of WO3, Mg, and C mixture and tested in a single cell mode at 80°C with Pt/C cathode (0.3 mg/cm ), Naflon 112 membrane, and H2/Air = 5. This electrocatalyst produced high current densities of 240 mA/cm (at 2 atm) and 280 mA/cm (at 3 atm) at 0.5 V, and an open circuit voltage of 0.95 V(152). These values represent the highest current density reported for WC-based anode in the literature. In the analysis, the material... 

Bartrom A M, et al. (2013) Optimization of an anode fabrication method for the alkaline Direct Formate Fuel Cell. J Power Sources 229 234-238. doi 10.1016/j. jpowsour.2012.12.007... 

Allam NK, El-Sayed MA (2010) Photoelectrochemical water oxidation characteristics of anodically fabricated Ti02 nanotube arrays structural and optical properties. J Phys Chem C 114(27) 12024-12029... 

Dongyan D et al (2009) Anodic fabrication and bioactivity of Nb-doped Ti02 nanotubes. Nanotechnology 20(30) 305103... 

Allam NK, Alamgir F, El-Sayed MA (2010) Enhanced photoas-sisted water electrolysis using vertically oriented anodically fabricated Ti—Nb—Zr—O mixed oxide nanotube arrays. ACS Nano 4(10) 5819-5826... 

Allam NK, Grimes CA (2009) Effect of rapid infrared annealing on the photoelectrochemical properties of anodically fabricated Xi02 nanotube arrays. J Phys Chem C 113(19) 7996-7999... 

Fukui, T., Ohara, S., Naito, M. Nogi, K. Pferformance and stability of SOFC anode fabricated from NiO/YSZ composite particles. J. Europ. Ceramic Soc. 23 (2003), pp. 2963-2967. 

As a pit, perhaps at a break in mill scale, becomes deeper, an oxygen concentration cell is started by depletion of oxygen in the pit. The rate of penetration by such pits is accelerated proportionately as the bottom of the pit becomes more anodic. Fabrication operations may crack mill scale and result in accelerated corrosion. 

MFC consists of an anodic chamber and cathodic chamber separated by CEM. The common designs of MFC include a single compartment, double compartment, upflow mode and stacked microbial fuel cell. The single compartment MFC possesses only one chamber, i.e., the anodic chamber. The cathode is either coupled to the anode, fabricated directly on the CEM or in tubular geometry with the anode. Figure 1.20a shows the single compartment MFC. 

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