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Fuel Cell
Published in Ramendra Sundar Dey, Taniya Purkait, Navpreet Kamboj, Manisha Das, Carbonaceous Materials and Future Energy, 2019
Ramendra Sundar Dey, Taniya Purkait, Navpreet Kamboj, Manisha Das
According to the choice of electrolyte and fuel, fuel cells are classified into six major categories as follows (Table 7.1): Proton exchange membrane fuel cell (PEMFC) Direct formic acid fuel cell (DFAFC)Direct ethanol fuel cell (DEFC)Alkaline fuel cell (AFC) Proton ceramic fuel cell (PCFC)Direct borohydride fuel cell (DBFC)Phosphoric acid fuel cell (PAFC)Molten carbonate fuel cell (MCFC)Solid oxide fuel cell (SOFC)Direct methanol fuel cell (DMFC)
New Class of Graphene Materials for Fuel Cells
Published in Shuhui Sun, Xueliang Sun, Zhongwei Chen, Yuyu Liu, David P. Wilkinson, Jiujun Zhang, Carbon Nanomaterials for Electrochemical Energy Technologies, 2017
Xin Tong, Qiliang Wei, Gaixia Zhang, Shuhui Sun
At the cathode of a proton exchange membrane fuel cell (PEMFC), oxygen is electrochemically reduced on catalyst surfaces through the oxygen reduction reaction (ORR). The reactions typically follow either a four-electron or a two-electron reduction pathway, and in general, the four-electron route is more efficient than the two-electron process for ORR (Figure 10.1a) [6,7]. At the anode side, various chemicals, including hydrogen, methanol, formic acid, and even ethanol, can be fed as fuels. For a direct hydrogen fuel cell (DHFC), the sluggish kinetics is mostly attributed to ORR, because the anodic reaction has a small overpotential due to the relatively easy-breaking H–H bond, and the corresponding hydrogen oxygen reaction (HOR) involves only two electrons (Figure 10.1b). For the direct methanol fuel cell (DMFC), however, the complete oxidation of methanol involves six electrons and has a large overpotential at the anodic half-cell for the methanol oxidation reaction (MOR) (Figure 10.1c). A dual pathway has been proposed for MOR, in which methanol can be oxidized either directly to CO2 or through the adsorbed COads intermediate. Similarly, in the direct formic acid fuel cell (DFAFC), the electrochemical oxidation of formic acid can also have two major possible pathways, forming CO2 either directly through the dehydrogenation process or via a dehydration step (Figure 10.1d).
Methanol and Formic Acid Oxidation: Selective Fuel Cell Processes
Published in Aneeya Kumar Samantara, Satyajit Ratha, Electrochemical Energy Conversion and Storage Systems for Future Sustainability, 2020
Tapan Kumar Behera, Pramod Kumar Satapathy, Priyabrat Mohapatra
As like methanol, FA also one type of PEMFC in which FA is directly used as fuel. FA is a small organic molecule and reasonably stable liquid at ambient condition of temperature and pressure. It is a natural biomass and a CO2 reduction product. The storage of FA is easy and safe than hydrogen. Nearly about five decades ago, the FAO fuel cell investigation started with the advent of modern potentiodynamic techniques. The oxidation of FA on nanocrystals is considered as a model reaction in electrocatalysis due its simple structure where only two electrons involved in the total FAO reaction process to yield carbon dioxide. In 1960s, electrochemistry fuel cell FA experiment performed by many pioneers and resulted (i) Clarifying the chemical nature of the active intermediate in the direct pathway, (ii) Diminishing CO adsorption on nanocrystal electrodes (iii) Phenomenological interpretation of anodic polarization curves for FAO (iv) Discover of the catalytic effect with respect to NPs for FAO (v) Concentration, temperature effects in a fuel cell. In direct formic acid fuel cell (DFAFC), it is oxidized to CO2 at anode, and oxygen reduction takes place at the cathode. The typical reactions in PEMFC are the proton passes to the cathode via PEM and reacts with oxygen on the catalyst layer at the cathode.
Structural and morphological characteristics of nanocrystalline palladium deposits prepared from ammonia complex by electrodeposition technique
Published in Transactions of the IMF, 2023
K. Ranjithkumar, K. Geetha, V. Prabu, S. M. Senthilkumar, R. Sekar
A non-aqueous solution such as ionic liquids (ILs) based palladium electrodeposition is the best alternative solution for aqueous electrodeposition. The electrochemistry response of palladium in chloroaluminate ILs was reported by Sun et al.16 In these solutions, Pd exists in the complex form [PdCl4]2- and deposited as Pd metal with black colour, the deposits are loosely bonded, powdery, and nodular dendritic at high current densities. However, deposits show a smooth morphology at low current densities.17 This consequently indicates the proportion of palladium coating and appearance is purely dependent on the deposition over-potentials. Palladium is a high efficiency electrocatalyst for its HER and ORR activity, mostly in fuel cells applications such as dual ethanol fuel cell (DEFC) and formic acid fuel cell (FAFC).18–26